Atlas of Earth's Meteor Showers 9780443235771

Table of contents :
Front Cover
ATLAS OF EARTH’S METEOR SHOWERS
ATLAS OF EARTH’S METEOR SHOWERS
Copyright
Contents
Preface
Acknowledgments
1 - Introduction
A brief introduction to meteor showers
Atlas scope and outline
2 - Methods
Explanation of the data presented
3 - Meteoroid orbit surveys
CAMS: The global Cameras for Allsky Meteor Surveillance network
CAMSS: The CAMS spectrograph
SonotaCo: The SonotaCo Network
GMN: The Global Meteor Network
SAAMER-OS: The Southern Argentina Agile Meteor Radar—Orbital System
JRO-Meteor: The Jicamarca radar as meteor head echo observatory
MAARSY: The Middle Atmosphere Alomar Radar System
MU radar: The MU radar as a meteor head echo observatory
AMOR: The advanced meteor orbit radar
4 - The Atlas: Overview and major showers
5. Allsky: Video and Radar
6 - Northern apex
7 - Southern apex
8 - Anthelion source
9 - Helion source
10 - Northern antapex
11 - Southern antapex
12 - North and south poles
Greek alphabet
Index
Back Cover

Citation preview

ATLAS OF EARTH’S METEOR SHOWERS

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ATLAS OF EARTH’S METEOR SHOWERS BY PETER JENNISKENS The SETI Institute, California

Elsevier Radarweg 29, PO Box 211, 1000 AE Amsterdam, Netherlands The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom 50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States Copyright © 2024 Elsevier Inc. All rights reserved. First published in the USA by Elsevier in 2023. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. ISBN: 978-0-443-23577-1 For information on all Elsevier publications visit our website at https://www.elsevier.com/books-and-journals Publisher: Candice Janco Acquisitions Editor: Peter Llewellyn Editorial Project Manager: Mason Malloy Production Project Manager: Paul Prasad Chandramohan Cover Designer: Vicky Pearson Esser Typeset by TNQ Technologies

To Peter S. Gural and the amateur astronomers worldwide who built and operate the CAMS camera network, for their enthusiasm, friendship, and devotion to map the skies

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Contents Preface ix Acknowledgments

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1. Introduction 1 2. Methods 5 3. Meteoroid orbit surveys 23 4. The Atlas: Overview and major showers 5. Allsky: Video and Radar

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6. Northern apex 227 7. Southern apex 409 8. Anthelion source 539 9. Helion source 671 10. Northern antapex

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11. Southern antapex

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12. North and south poles

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Greek alphabet 806 Index 807

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Preface Starting about 15 years ago, video- and radar-based meteoroid orbit surveys dramatically scaled up the measurement of meteoroid trajectories and orbits. At the end of 2020, over two million orbits have been measured by video cameras and about 25 million by radar, covering both hemispheres. For over a century before that, visual observers had plotted meteor trails on star maps in search of new meteor showers. Facing a group of meteors on parallel trajectories, they would appear to radiate from a common point in the sky, called the “radiant.” Despite untold hours scanning the skies, our knowledge of meteor showers remained poor. Photography and radar-based meteoroid orbit surveys provided the first instrumentally recorded data. They started in earnest in the 1950s and 1960s, but by the end of the century the average number of measured orbits had reached only a handful for each night. Based on this early photographic and radar data, I listed 275 possible showers into a “Working List of Cometary Meteor Showers” in my previous 2006 book, Meteor Showers and their Parent Comets. The numbered entries in this table, together with a “Working List of possible Asteroidal Meteor Showers” and the unnumbered table of possible high southern declination showers on page 517, were entered into the IAU Working List of Meteor Showers as IAU numbers 1 through 318. Because they were proposed from so little data, only about 38% are now confirmed. In recent years, the number of detected showers has grown so large that a new confusion has set in. Many newly reported showers to the IAU Working List of Meteor Showers are duplicates of already listed showers. Showers based on poor early data remain in the list. This Atlas of Earth’s Meteor Showers aims to resolve some of that new confusion by going back to the original data and search for clusters in video-based and radar-based maps of meteor radiants. About 402 of the 857 meteor showers (47%) in the Working List up to number 1031 are confirmed here. Another 108 new meteor showers were identified during this work. In total, 513 meteor showers are now documented, 26 of which remain unique to radar detection. New meteor showers will be recognized as more data are collected and faint showers are resolved. In addition, some showers are episodic, return rarely, or are singular events because the orbits of meteoroid streams and their sources evolve over time. The showers presented in this Atlas are a snapshot in time and will need updates in the future. Peter Jenniskens

Mountain View, California, USA

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Acknowledgments Previously detected meteor showers published in the literature are summarized in the online IAU Working List of Meteor Showers, maintained by the IAU Meteor Data Center in Poznan and Bratislava (T. Jopek, M. Hajdukova, and R. Rudawska), at the website: https:// www.iaumeteordatacenter.org/ (last accessed Aug 14, 2023). The showers in the IAU Working List were checked against published orbit data from video-based meteoroid orbit surveys on both the northern and southern hemisphere, 2.7 million orbits of which are from the Cameras for Allsky Meteor Surveillance (CAMS) project. We thank the CAMS station operators who maintain the video cameras, the network coordinators, and Dave Samuels and Steve Rau for the global network software install and maintenance. Many network coordinators (underlined) and station operators are amateur astronomers and citizen scientists, but a host of professional institutes also support the CAMS effort. A partial list of participants (with CAMS Catalog network numbers): #1 CAMS California: P. Jenniskens (SETI Institute, NASA Ames Research Center), J. Albers, R. Morales, E. Egland (FPOA), B. Grigsby (UCO/Lick), J. D. Wray, D. Samuels, G. Newell, and D. Drumheller; #2 CAMS Florida: A. Howell, B. Harris, C. Palotai and A. Hughes (FIT), E. Kisvarsanyi (CCF), and J. Cheney; #3 CAMS BeNeLux: C. Johannink, M. Breukers, P. Roggemans, A. Roggemans, S. Rau, K. Miskotte, K. Jobse, K. Habraken, J. M. Biets, H. Lamy, T. Polvliet, B. Dessoy, R. Haas, C. Wanlin, J.-P. Dumoulin, E. van Ballegoij, T. J. Dijkema, U. Glaessner, L. Boergerding, R. Kuehn, G. Canonaco, L. Gobin, T. Gulon, P. Neels, P. Lindsay, J. Nijland, H. Betlem, F. Bettonvil, H. Schremmer, M. van der Weide, P. de Ponthierre, J. Rowe, R. Kühn, and P. Schaack; #4 CAMS Mid-Atlantic: P. Gural, G. Varros, B. Smith, and K. Jamrogowicz; #5 CAMS New Zealand: J. Baggaley (University of Canterbury), I. Crumpton, P. Aldous, N. Frost, C. Duncan, L. Duncan, and J. Scott; #6 Lowell Observatory CAMS, Arizona: N. Moskovitz (Lowell Observatory), B. Rachford (ERAU), M. Gialluca, R. Schottland, M. Francis, M. Wheeler, M. Cheselka, J. Glitsos, B. Broffel, B. Sorrell, D. Avner, S. Blomquist, and S. Hemmelgarn; #7 United Arab Emirates Astronomical Camera Network: M. Odeh (IAC), K. Al-Noaimy, O. Ghannam, A. Mohammad, S. Al-Afifi, and H. Al-Rumaithi; #8 CAMS South Africa: T. Cooper, P. Mey (HartRAO); #9 CAMS EXOSS, Brazil: M. De Cicco, L. Fontes, G. Silva, L. Horta, W. Eugenio, M. F. Rosa, M. Severiano, W. Souza, C. H. Barreto, L. D. Aguiar, J. A. Maiworm, J. E. Nunes, O. M. Alflen, G. Negri, A. Fonseca, A. Rondini, D. Montorini, L. G. Oran, M. Mastria, S. C. De Paula, I. Rodrigues, W. M. Jesus, E. P. Santiago, G. Rescigno, D. De Bastiani, R. A. Cardial, S. Gargaglioli (OPD-LNA), D. Lazzaro (OASI - ON), C. R. B. Pereira, A. D. Bertiol and D. A. Brissi (IFSP Birigui), C. Souza and E. L. Oliveira (DCTA), E.L L. Zappa (Fazenda Vira Mundo), T. Rangel (UFMS Pantanal), and J. Lobo (OMC). #10 CAMS Northern California: T. Beck (Mendocino College), M. Bradley; #14 CAMS Arkansas: L. Juneau, and S. Austin (UCA);

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ACKNOWLEDGMENTS

#15 CAMS Australia: M. Towner (Curtin University), M. Cuprak, C. Redford, L. Toms, G. Kelaher, H. Devillepoix, and D. Rollinson; #16 CAMS Chile: S. Heathcote (AURA/CTIO), T. Abbott, J. Rojas, D. Rojas, H. Orrego, and E. Jehin (U. of Liège); #17 CAMS Namibia: T. Hanke (H.E.S.S. Collaboration), E. Fahl, and R. van Wyk; #19 CAMS Texas: W. Cooney, D. Selle, F. Cyrway, J. Brewer, and D. Samuels; #21 CAMS Turkey: O. Unsalan (Ege University), M. Boyukata, I. Kilic, O. Arslan, A. Dervisoglu, and I. Kucuk. In addition to CAMS data, the video maps show the results from unaffiliated networks, some of which are introduced in Chapter 3. This includes the about 356,000 published orbits from the (#11) SonotaCo network, coordinated by T. Kanamori (data published at http:// sonotaco.jp/doc/SNM/, last accessed May 2021), the about 30,000 orbits from the (#12) Croatian Meteor Network (D. Segon) published at http://cmn.rgn.hr/ (last accessed Nov. 5, 2022) that are not included in the EDMOND database, and the first 390,000 orbits from the recently established (#20) Global Meteor Network (D. Vida, data published at https:// globalmeteornetwork.org/data/ and used under CC BY 4.0 license), and the about 300,000 published orbits in the (#13) European viDeo Meteor Observation Network (EDMOND) database (L. Kornos, data published at https://fmph.uniba.sk/en/microsites/daa/divisionof-astronomy-and-astrophysics/research/meteors/edmond/, last accessed May 2021). Contributors to EDMOND included the following organizations: BOAM (Base des Observateurs Amateurs de Meteores, France), CEMeNt (Central European Meteor Network, crossborder network of Czech and Slovak amateur observers), CMN (Croatian Meteor Network or Hrvatska Meteorska Mreza, Croatia), DMS (the Dutch Meteor Society), FMA (Fachgruppe Meteorastronomie, Switzerland), HMN (Hungarian Meteor Network or Magyar Hullocsillagok Egyesulet, Hungary), IMO VMN (The International Meteor Organization’s Video Meteor Network), MeteorsUA (Ukraine), IMTN (Italian amateur observers in Italian Meteor and TLE Network, Italy), NEMETODE (Network for Meteor Triangulation and Orbit Determination, United Kingdom), PFN (Polish Fireball Network or Pracownia Komet i Meteorow, PkiM, Poland), Stjerneskud (Danish all-sky fireball cameras network, Denmark), SVMN (Slovak Video Meteor Network, Slovakia), and UKMON (UK Meteor Observation Network, United Kingdom). The reported showers were also checked against data from radar-based orbit surveys. Few data sets are in the public domain. This book was made possible by D. Janches of NASA Goddard Space Flight Center, who kindly made the large 2017e2020 southern hemisphere SAAMER-OS dataset available. SAAMER-OS is a specular meteor orbit radar located in southern Argentina. S. Bruzzone verified the new SAAMER-OS detected showers. Also from the southern hemisphere, J. Chau made available the meteor echo orbit database obtained at the Jicamarca Radio Observatory, a HAPLA radar that can detect smaller meteoroids. For radar data from the northern hemisphere, we thank G. Stober for making available the specular MAARSY dataset for this Atlas and J. Kero for making available the meteoroid orbits obtained with the MU Radar in Japan, a HAPLA radar. In addition, the southern hemisphere AMOR radar orbits were kindly recovered for this project by W. J. Baggaley. The northern hemisphere specular CMOR orbit dataset was not made available. Much of the physical data on meteor showers is based on an analysis of CAMS and CAMS Spectrograph data alone. Peter S. Gural developed the meteor detection algorithms for CAMS and wrote the CAMS software tools for calibration and triangulation. He also played a role in the development of the CMN and GMN network software by validating results against

ACKNOWLEDGMENTS

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CAMS calculations. The CAMS and CAMSS software was written from the ground up, but has some roots in the FIRBAL software used by the Dutch Meteor Society (DMS) small camera network, written by Z. Ceplecha. I thank H. Betlem and R. Veltman of DMS for introducing me to this field. Many SETI Institute students and interns helped with the early data reduction of CAMS. In particular, I thank B. Haberman, B. Johnson, D. Holman, B. Kelley, A. Crump, H. Duckworth, M. Phillips, K. Steakley, S. Valkov, L. Genovese, M. Hannan, A. Berdeu, Q. Nenon, K. Newman, M. Borden, and M. Koop. Automation of the CAMS data processing was spearheaded by J. Collison, S. Ganju, S. Ambardar, and P. Gural. The on-line CAMS data visualization was made into a public outreach tool (at https:// meteorshowers.seti.org/, last accessed Aug. 14, 2023) by S. Ganju, A. Hatua, C.-C. Ren, S. Krishna, and C. Roffey. Some maps from this site are shown. I. Webster (Google Space) created the online interactive planetarium program that visualizes the orbits of CAMSdetected meteoroids in the solar system at: https://www.meteorshowers.org/, last accessed Aug. 14, 2023, screen shots of which are shown in this Atlas. The distributed CAMS BeNeLux does its own data processing and I thank C. Johannink and M. Breukers of DMS for their continued support as coordinators of the CAMS BeNeLux network. .

Further contributions to this book include calculations of shower visibilities and shower ages by S. Pilorz of the SETI Institute. He also adapted the PINTEM software kindly made available by J. Vaubaillon (Institut de Mécanique Céleste et de Calcul des Éphémérides) and calculated ages of long-period comet showers. Careful reviews of the manuscript were provided by T. Cooper (CAMS South Africa, Astronomical Society of Southern Africa) and J. Wood (NAPO-MS) for southern hemisphere video showers, C. Johannink and K. Miskotte (Dutch Meteor Society) for the northern hemisphere video showers, D. Holman (International Meteor Organization) for shower nomenclature and radiant verification using his software MOAT, and by D. Janches (NASA Goddard) and G. Stober (Leibniz Institute of Atmospheric Physics) for a review of the southern and northern Hemisphere radar showers, respectively. I thank my wife Charlie Hasselbach for her supporting care, and my friends in the professional and amateur meteor astronomy communities for their contributions and unwavering support. I also thank the staff at the SETI Institute for program support and maintenance of the CAMS IT environment, especially D. Kolyer, Y. Nicholas, B. Vance, B. Simmons, S. Smith, S. Brockbank and A. Malonzo, and the Frontier Development Lab program for enabling the CAMS network automation. This work was supported by NASA Grants 80NSSC19K0563 (Solar System Workings), 80NSSC19K0513 (Emerging Worlds), and NNH21ZDA001N (Yearly Opportunities for Research in Planetary Defense). We thank the program managers at NASA, the Planetary Defense Coordination Office, and NASA Ames Research Center for their support. The domestic and global expansion of CAMS was made possible by the private support from CAMS station operators and that from affiliated local organizations. LO-CAMS was expanded with support from an NSF CAREER award (project ID AST-1944827). The UAE Astronomical Camera Network is supported by the UAE Government. CAMS Turkey operates as part of the TUBITAK-1001 project (MFAG/113F035). The CAMS survey of the southern hemisphere was made possible by an expansion facilitated by D. Lauretta of the University of Arizona and the OSIRIS-REx mission, based upon work supported by NASA under Contract NNM10AA11C issued through the New Frontiers Program. This created the first video-based near all-sky view of meteor showers.

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C H A P T E R

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Introduction

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Introduction

A brief introduction to meteor showers On its journey around the Sun, the Earth meets numerous streams of solid particles called meteoroids. Those enter Earth’s atmosphere at high speed (between 11 and 72 km per second), collide with the air molecules, fragment, melt and evaporate, and in doing so shine bright as meteors. Meteors are commonly known as “shooting stars.” Meteoroid streams are groups of such meteoroids that originated from the same parent body and still move along similar orbits around the Sun. Meteoroid streams cause meteor showers [1]. Meteor showers are a unique window on the universe around us. A shooting star signals that a distant comet or primitive asteroid long ago released a stream of solid particles. A stream now so dilute that it often can not be detected by other techniques. That stream evolved over time and now is a trail of crumbs pointing to comets on dangerous paths that one day may intersect that of Earth. And even though the meteoroids themselves are tiny, only millimeter or centimeter sized, they are dangerous to satellites in orbit because of their high speed. While the meteoroid moves through Earth’s atmosphere, even for just a brief moment, the direction of motion (called the radiant) and the speed can be measured by cameras or by radar. The bright light from the collisions with air molecules can be triangulated by video cameras. Fig. 1.1, for example, shows that direction of motion and speed from meteors detected by video cameras on December 3, 2021. These collisions also generate electrons. Radars track the motion of a meteoroid by reflecting radio waves off those electrons. The measured radiant and speed define the orbit of the meteoroid around the Sun. Strictly speaking, they define the shape and orientation of the orbit ellipse just before entering Earth’s atmosphere. By measuring those orbits, the ongoing orbit surveys chart the meteoroid streams in our solar system. Since 2006, the International Astronomical Union (IAU) assigns formal names to meteor showers [2e6]. When a new shower is first detected, observers can propose a name to the Meteor Data Center, who maintains the IAU Working List of Meteor Showers. The Meteor Data Center makes sure that the naming of showers in the literature remains unique. Every 3 years, the IAU Working Group on Meteor Shower Nomenclature selects the well observed showers from that list for formal naming.

Atlas scope and outline This Atlas of Earth’s Meteor Showers is an attempt to take stock and provide a “birder’s guide to meteor showers,” if you like. A selected number of maps were created that show each shower and the surrounding sporadic meteor activity in as few maps as possible. The different chapters focus on certain directions in the sky, so that the format of the maps stays more or less the same in each chapter. An index is provided to help find a particular shower. As in a birder’s guide, each shower’s plumage is described, its range and prevalence, and the history of the name given. That plumage includes the median orbit and the dispersion in the orbits, as well as how the median orbit changes along Earth’s path (the drift). Used in dynamical modeling, this data can help identify the stream’s parent body and determine the stream’s age. The showers are characterized by whether they are rich in bright meteors or rich in faint meteors. A stream being rich in small particles, causing faint meteors, can point to the collisional conditions during formation of a stream, or it can point to changes induced by the heat of the Sun or other processes of “space weathering” in the interplanetary medium ever since.

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FIG 1.1 Celestial sphere with stars as black points and star constellation asterisms drawn by lines. White and colored points show the direction from which meteors appeared to approach Earth on December 3, 2021. Showers are the blobs marked with colors. Three-letter codes label the showers as December alpha-Draconids (DAD, #334), December kappa-Draconids (DKD, #336), psi-Ursae Majorids (PSU, #339), Comea Berenicids (COM, #20), Leonids (LEO, #13), Geminids (GEM, #4), Northern Taurids (NTA, #17), Southern chi-Orionids (ORS, #257), Southern Taurids (STA, #2), November Orionids (NOO, #250), December Monocerotids (MON, #19), sigma-Hydrids (HYD, #16), thetaPyxidids (TPY, #340), and lambda-Velids (LVL, #303). Created from: https://meteorshowers.seti.org.

Indeed, streams can be created rich in large meteoroids, but then preferentially loose those over time by breaking up. Meteoroids can be either dense solid rocks or loosely stacked assemblages of various minerals and organic matter. Solid meteoroids will tend to have a higher density and decelerate more slowly in collisions with the atmosphere. If meteoroids are fragile, they fragment easily during atmospheric entry. Some meteors start glowing high up in the atmosphere, others only further down. The altitude where they first emit sufficient light to be detected depends on how efficient heat is conducted into the meteoroid, or how volatile the mineral components are.

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Introduction

The harsh conditions in the interplanetary medium can change their physical properties. The heat of the Sun, for example, can lead to the loss of minerals containing sodium compared to the core minerals that are rich in magnesium. The loss of sodium can be detected in meteor spectra. For each meteor shower, a table of information is given on the period of activity, radiant, speed, and orbital elements, the dispersion in the orbital elements, and available physical information based on meteor light curves, deceleration, and spectroscopy. The accuracy of this information depends on the number of meteors detected from a given shower, how well the shower was isolated from the sporadic background, and if the observational data is correctly interpreted. Where available, the results from the analysis of data presented here are compared to literature data. Finally a fully referenced “brief history” is provided for each shower that describes the origin of the name, three letter code and number of the shower, when the shower was first recognized, when it was confirmed by other observational techniques, and when key parameters were first determined, including from dynamical models. References are given for further reading. References: [1] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: Cambridge University Press, 790 pp.; [2] Jenniskens P., Jopek T. J., Janches D., Hajdukova M., Kokhirova G.I., Rudawska R. (2020) PPS 182, article id. 104821; [3] Jopek T.J., Kanuchova Z. (2017) PSS 143, 3e6; [4] Jopek T.J., Kanuchova Z. (2014) In: The Meteoroids 2013, Proceedings of the Astronomical Conference held at A.M. University, Poznan, Poland, Aug. 26e30, 2013, Eds.: T.J. Jopek, F.J.M. Rietmeijer, J. Watanabe, I.P. Williams, Poznan: A.M. University Press, p. 353e364; [5] Jopek T.J., Jenniskens P. (2011) In: Meteoroids: The Smallest Solar System Bodies, Ed.: W. J. Cooke, D. E. Moser, B. F. Hardin, and D. Janches. Huntsville: NASA/ CP-2011-216469., p. 7e13.; [6] Rudawska R., Hajdukova M., Jopek T. J., Neslusan L. Jakubik M., Svoren J. (2021) JIMO 49, 163e168.

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Methods

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Methods

Explanation of the data presented Shower name and notation: Meteor showers are characterized by solar longitude (time), radiant coordinates (direction on the sky), and velocity (entry speed). The Perseids arrive from the constellation Perseus during maximum activity (Fig. 2.1). Many names are more specific, for example, the a-Capricornids arrive from a position nearby the star alpha Capricorni. In this Atlas, each shower is named by its IAU number (“7” for the Perseids), the IAU assigned 3-letter code (“PER”), and the assigned name (“Perseids”). To help their identification as much as possible, all three identifiers are given as “7 PERdPerseids.” There are many notation conventions in the literature, but here we keep the following. Greek letters are given in lower case as they refer to lower case Greek letters. Hence “1 CAPd alpha Capricornids”. In this notation, no hyphen is placed between the Greek letter and the name, as another hyphen is already placed between the code and name. However, when the shower name is mentioned without the number and code preceding it, there is a short hyphen between “alpha” and Capricornids: a-Capricornids. This is to clarify alpha belongs to Capricornids and that “15-Bootids” does not mean a collection of 15 Bootids.

FIG 2.1 Radiants during the Perseid meteor shower, color coded according to velocity (red fast, blue slow). Stars to magnitude þ3 are shown. Perseid radiants (shower #7) in the upper right are indicated as “7.”

Time and activity period: Each shower is active for a period of time, centered on a given date and time in the year. The meteors approach from a given direction in the sky known as the radiant, which can be compact or diffuse. The meteors can also enter at low or high speed

7 and with a range of values depending on how the meteoroid stream has dispersed. All these parameters can change as a function of where Earth is in its orbit (the solar longitude).

August 13 (lo ¼ 140 ) Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo):

7 PERdPerseids Long-period comet shower, TJ ¼ 0.01  0.42 Annual shower, occasional outbursts 1992: lo ¼ 139.453 , ZHR ¼ 550 /h, W ¼ 0.054 , July 18dSeptember 18 (lo ¼ 115 e175 ) lo ( ) R.A. ( ) Decl. ( ) 140.1 47.9 þ57.9 þ1.45 þ0.20

c ¼ 2.05  0.05 [1] l ( ) 283.0 þ0.02

b ( ) þ38.4 0.08

d1862 or Fil Vg (km/s) 58.8 þ0.03

In this Atlas, time is given first as an approximate calendar day. A more appropriate measure of time is the position of Earth in it’s orbit, expressed as solar longitude lo, the apparent direction of the Sun in the ecliptic plane as seen from the center of the Earth. Because there are 365.25 days in a year, covered by 360 in solar longitude, the day can be off by one due to rounding error.

Shower radiant/speed Median (geocentric): Drift per day (d/dlo):

lo ( ) 140.1

R.A. ( ) 47.9 þ1.45

Decl. ( ) þ57.9 þ0.20

l ( ) 283.0 þ0.02

b ( ) þ38.4 0.08

Vg (km/s) 58.8 þ0.03

Shower radiant/speed: To avoid distortions due to outliers, we present here the median values of radiant coordinates, time, and speed, not the mean values. The equatorial coordinates of the radiant are expressed in Right Ascension (R.A.) and Declination (Decl.) in units of degrees ( ). The daily change of R.A. and Decl. are also given, strictly the change per 1 in solar longitude. The direction to stars are the basis of naming meteor showers and the position of a star is often expressed in Right Ascension and Declination coordinates (Fig. 2.1). This is a coordinate system relative to Earth’s equator, meaningful for aiming telescopes. Meteoroid streams, however, have no knowledge of Earth’s equator. The plane of motion of Earth, the ecliptic plane, is more relevant to capture the north-south symmetry of the gravitational pull of the planets. Moreover, because of Earth’s motion around the Sun, the relevant directions are not just North, South, but also the direction of Earth’s motion and, 90 from that, the direction of the Sun. Hence, a more appropriate set of coordinates are the Suncentered ecliptic radiant coordinates l (longitude) and b (latitude). The radiant coordinates (R.A., Decl.) are first converted to ecliptic coordinates by removing the 23 tilt of Earth’s equator relative to the ecliptic plane, and then the ecliptic longitude is converted into a Suncentered ecliptic longitude by subtracting the solar longitude (Fig. 2.2). All maps in this Atlas are presented in terms of these Sun-centered ecliptic radiant coordinates (l, b). The use of these coordinates takes out much of the daily radiant drift due to Earth’s curved path around the Sun. However, we found that a slightly better definition of the shower radiants in the Anthelion and Helion sources is obtained after adding an additional correction to the radiant longitude of þ0.3 /day. This is due to the Sun-focused dispersion of these orbits. In this Atlas, we corrected this drift in most of the maps by calculating the values for a solar longitude at the center of that map’s time interval and using a daily drift of 1.3 per solar

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longitude instead of 1.0 . In the header of these maps, this is shown as “110.0e120.0 , to 115 ” or “110e120 > 115 ,” for example, when the map shows radiants obtained in the solar longitude interval of 110.0e120.0 (e.g., Fig. 2.2).

FIG 2.2 Distribution of meteor radiants in Sun-centered ecliptic coordinates during July 23eAugust 22.

Shower radiant/speed Median (geocentric): Drift per day (d/dlo):

lo ( ) 140.1

R.A. ( ) 47.9 þ1.45

Decl. ( ) þ57.9 þ0.20

l ( ) 283.0 þ0.02

b ( ) þ38.4 0.08

Vg (km/s) 58.8 þ0.03

The median geocentric speed at the start of the observed meteor trajectory is given and is expressed as Vg in units of kilometers per second (km/s). Velocity outliers were removed. The geocentric speed differs from the apparent speed in that the effects of Earth’s gravity and spin are removed. When meteoroids fall in the gravity well of Earth alone, they reach 11 km per second at the top of the Earth’s surface (adding or subtracting a small fraction from the spin of Earth itself, depending on where on Earth a meteor is observed and the time of night). They also tend to slightly change their path, called the zenith attraction. Removing both Earth gravity and spin in the apparent radiant coordinates and speed produces the “geocentric” coordinates (R.A., Decl.) and speed (Vg) reported in this Atlas. The term is called “geocentric” because the effect of Earth’s motion around the Sun is not removed. When meteoroids fall in the gravity well of the Sun, they reach 42 km/s at Earth’s orbit. But Earth’s motion around the Sun can add up to 30 km/s in a head-on collision, for a

9 maximum collision speed of 72 km/s. While apparent speeds range from 11 to 72 km/s, the geocentric velocities are between 0 and 72 km/s and are a strong function of the radiant position relative to Earth’s motion. This Atlas shows some maps color-coded by velocity, producing a bulls-eye pattern centered on the direction of Earth’s motion (the Apex). Some maps are also shown in “heliocentric” coordinates, after removing Earth’s velocity vector. Map projection and scale: The maps in this Atlas are plotted in simple rectangular coordinates, in order to make it easy to read off coordinates. No effort was made to depict the actual shape of the radiant area on the celestial hemisphere. Most maps have the ecliptic plane at the center (Chapters 4, 5, 8, and 9) or at the top or bottom of the map (Chapters 6, 7, 10, and 11), except for the maps in polar projection, which have the ecliptic pole as the center (Chapter 12). Different maps show differently sized areas on the sky, but most maps have a X/Y axis ratio in pixels of around 1.65, most equivalent to showing square degrees in the elongated plots. More particularly, the maps have these axis proportions: 50  30 ratio 1.67; 60  35 ratio 1.71; 70  40 ratio 1.75; 100  60 ratio 1.67; 120  70 ratio 1.71; 130  80 ratio 1.63; 150  90 ratio 1.67; 220  120 ratio 1.83; 360  180 ratio 2.00. Orbit surveys: Each graph has a header line that identifies what dataset is shown in the map. The meteoroid orbit surveys in Table 2.1, labeled “Yes” contributed data. The IAU Meteor Data Center provided the data obtained prior to 2003 CE. This is a relatively small amount of orbits. The early radar orbits are shown together as “Radar ALL”. The large SAAMER set is shown separately, as are the MU Radar, MAARSY, and AMOR data sets. Radiant and orbital elements are given separately for video and radar data. The symbol “eV” indicates that the results are derived from video observations. “eR” indicates radar data, with R[S] being SAAMER data, R[M] MAARSY results, R[MU] MU Radar results, and R[H] Harvard Meteor Project data. If a number is added, e.g., [1], it quotes literature data from references in the “Reference” section. Orbital elements: The meteor showers were extracted by visually searching in time for a cluster of radiants and speed distinct from the sporadic background. Each map contained the combined data over intervals of 1e3 in solar longitude, equivalent to 1e3 days in time. That approach seems naive and is time-consuming, but is efficient. Other search techniques look for similar orbits using so-called D-criteria, but that can easily lead to false detections. Even the sporadic background has many similar orbits. Statistical tools (such as a hat function) can be used to search for clusters, but if the distribution of radiants is wider or more elongated than described by the search function, these algorithms tend to break up a continuous feature into separate components. A visual check would still be required. In recent years, modern artificial intelligence techniques have been developed that can also recognize clusters, but those need to then also be visually verified.

Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo):

a (AU) 12.7

q (AU) 0.948 0.026 0.0007

e 0.926 0.155 0.0014

i ( ) 112.8 3.4 þ0.11

u ( ) 150.0 6.5 0.12

U ( ) 139.6 5.7 þ1.00

P ( ) 288.4 8.2 þ0.88

eV

Once a shower has been extracted, the median orbital elements are calculated. The semimajor axis (a) describes half the long axis of a meteoroid’s orbit ellipse. The unit is Astronomical Unit (AU), the mean distance between the centers of Earth and Sun. 1/a, rather than a, is the measured value. The perihelion distance (q) describes how close the meteoroid approaches the Sun, has the same unit of AU, and ranges from about 0.03 to 1.03 AU. The

10

Methods

TABLE 2.1 Overview of the main meteoroid orbit surveys. Type

Name

Location

Years

Norb

LM

References

Incl

Photo Photo Photo Photo Photo Photo Photo Photo Photo Photo Photo Photo Photo Photo

Small Camera Small Camera Super-Schmidt Small Camera EN Small Camera Small Camera Prairy Network TMN MORP DMS

Massachusetts, USA Dushanbe, USSR New Mexico, USA Czechoslovakia Central Europe Kiev, USSR Odessa, USSR Western USA Japan Western Canada The Netherlands New Mexico, USA Alabama, USA France, Italy

1936e1952 1940e1983 1952e1959 1955e1959 1955e1990 1957e1981 1957e1983 1963e1975 1964e1989 1971e1985 1972e2001 1974e1977 2021e2021 2021e2021

171 639 3138 109 189 206 459 336 339 365 1344 25 589 589

w0 wþ1 þ2 þ3 6 wþ1 wþ1 3 wþ2 5 w0 w0 6 6

[1] [2e4] [5e7] [8,9] [10] [4,11] [3,4] [12] [4] [13e15] [16,17] [18] [19] [20]

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Jodrell Bank, UK Kharkiv, Ukraine Adelaide, Australia Havana, IL, USA Obninsk, USSR Kazan, USSR Adelaide, Australia Havana, IL, USA Mogadishu, Somalia Kharkiv, Ukraine Christchurch, NZ Christchurch, NZ Kwajalein, Marshall Jicamarca, Peru London, Canada Shigaraki, Japan London, Canada Norway Rio Grande, Argent.

1954e1955 1959e1965 1960e1961 1961e1965 1967e1968 1968 1968e1969 1968e1969 1968e1970 1975 1989e1994 1995e2003 1998 2001e2009 2002e2007 2009e2020 2008e2019 2013e2019 2017e2020

2509 12,500 2092 19,327 9358 3200 1667 19,818 5328 5317 300,000 500,000 9990 322,090 2,000,000 211,358 11,000,000 1,499,365 10,153,446

þ7 þ7 þ6 þ10 þ7.5 þ8 þ8 þ10 þ8 þ12 þ12 þ14 þ11 þ10 þ8 þ12 þ8 þ9 þ9

[21] [22] [23] [24,25] [26,27] [28,29] [30] [25,31] [32,33] [34] [35,36] [37] [38] [39] [40,41] [42] [43] [44] [45,46]

Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No Yes No Yes No Yes Yes

London, Canada Japan The Netherlands Czech Republic Europe Japan Global network Croatia Global network

1981e1982 1983e2006 1991e2000 1998e2001 2003e2016 2007e2021 2010e2023 2016e2018 2018e2021

454 3491 1112 842 321,229 356,171 2,704,966 27,902 390,584

þ8.5 þ7.2 þ6 þ5 þ3 þ2 þ5 þ3 þ5

[47] [48] [49,50] [51] [52,53] [54] [55] [56] [57]

Yes Yes Yes Yes Yes Yes Yes Yes Yes

Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar Radar TV TV TV TV TV TV TV TV TV

ASGARD FRIPON

HMP

Harv. Syn. Year Equatorial Sur. AMOR AMOR ALTAIR JRO CMOR MU Radar CMOR MAARSY SAAMER NMS DMS EDMOND SonotaCo CAMS CMN GMN

Incl.: data were available for use in this Atlas. Notes: Updated version of earlier compilations by [4,39,62,69]. AMOR, Advanced Meteor Orbit Radar (Point of contact: J. Baggaley); CMN, Croatian Meteor Network (D. Segon); CMOR, Canadian Meteor Orbit Radar (P. Brown); DMS, Dutch Meteor Society (H. Betlem); EDMOND, European Meteor Video Network Database (L. Kornos, J. Koukal); EN, European Fireball Network (Z. Ceplecha); GMN, Global Meteor Network (D. Vida); HMP, Harvard Meteor Project (Z. Sekanina); LM, limiting magnitude; MAARSY, Middle Atmosphere Alomar Radar System (G. Stober); MORP, Meteorite Orbit and Recovery Project (I. Halliday); MU Radar, Middle and Upper Atmosphere Radar (J. Kero); NMS, Nippon Meteor Society (M. Koseki); SAAMER, Southern Argentina Agile MEteor Radar (D. Janches); SonotaCo, Sonotaco Consortium (T. Kanamori).

eccentricity (e) describes the elongation of the ellipse, with q ¼ a (1  e). The published median values of q, a and e do not follow this equation exactly. The inclination (i) describes how steep the meteoroid orbit is inclined relative to the ecliptic plane (0e360 ). The argument of

11 perihelion (u) is the angle between the nodal line and line toward perihelion. The ascending node (U) defines where the nodal line intersects Earth’s orbit. The longitude of perihelion P ¼ u þ U. Each table also contains the dispersion of the orbital elements (s, one standard deviation) at a given solar longitude lo and the drift as a function of lo. The symbol “y” is a warning that indicates that the drift is not linear with lo. Note that the dispersion in Node at a given solar longitude is meaningless, so instead the standard deviation of the distribution of nodes is given, proportional to the duration of the shower. When using these numbers, keep in mind that the dispersions in the orbital elements follow from those in Time, Right Ascension, Declination, and Speed (not given separately). Each has a measurement uncertainty. Time is measured more precisely than the natural dispersion of meteoroids in Earth’s path (solar longitude, node). The radiant position is almost always measured more precisely than the natural dispersion, except in the case of meteor outbursts from recent comet ejecta, and contributes strongly to the dispersion in inclination, perihelion distance, and argument of perihelion. The speed is rarely measured more precisely than the natural dispersion and that mostly affects the uncertain dispersion of eccentricity. Radar-derived orbital elements are given as a separate block if the shower is also detected by video. The geocentric velocity derived from radar data is often lower than that derived from video data. The resulting semi-major axis of the orbits is also lower. Sometimes, this lower semi-major axis may be a real effect because radars detect smaller meteoroids than do video cameras, but in most cases this is an instrumental effect. We find the worst discrepancy when the beginning altitude of the meteors is high (low calculated density for the videodetected meteors). Specular (mirror-like reflecting) radars are not as sensitive at high altitude because meteor generated electrons disperse more rapidly there. Because of this, the orbits of fast and low density meteoroids tend to be too short. Dynamic type: Meteors in orange and red in Fig. 2.2 are mostly long-period and Mellishtype comet showers or sporadics from the apex source (in the direction of Earth’s motion). There is a northern apex source and a southern apex source, because planets perturb orbits near the ecliptic plane. In blue to the left of Fig. 2.2 are meteors from the anthelion source (opposite the Sun). These are mostly meteors that move in Jupiter-family comet type orbits. In yellow and green are the sun-skirting steams, with small perihelion distance 3.50). Those borders reflect the observed distribution of median Tisserand parameters of meteor showers (see Fig. 2.3), not the dynamical state of the parent body (dashed line).

12

Methods

The “toroidal” source consists of meteoroids in highly inclined i w 60 orbits and is named this way because these orbits form a cylindrical toroid in space [58]. “Mellishtype” showers are mostly prograde highly inclined (i ¼ 20 e80 ) showers in the toroidal source and they are called “Mellish-type” here because the December Monocerotids of comet C/1917 F1 (Mellish) is the lowest-numbered example. Dynamical models suggest they originated mostly from Halley-type comets, but can also originate from Jupiter-family type comets, and even from asteroids. Halley-type comets 1P/Halley, 109P/Swift-Tuttle, and 55P/ Tempel-Tuttle have “Long-period comet” FIG 2.3 F-value versus Tisserand parameter. type meteor showers. The “Asteroid” moniker is used even more sparingly, as evolved Jupiter-family comet showers also have high Tisserand parameters [59]. Other classifiers given include “sunskirter” used to indicate streams that approach the Sun to within q  0.15 AU. Below the gray box with orbital elements are a number of other parameters given. Our goal here is to highlight differences among showers in the data, and present that data by taking the most straightforward interpretation possible. The following items are included:

Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Lightcurve shape: Meteoroid density:

Strength: Spectroscopy: Age:

N ¼ 141,260 (hr ¼ 47.0 , m(Mv ¼ 0) ¼ 0.03 g) ZHR ¼ 84  5/h [18] Peak: 2.36  0.03 (s ¼ 1.93  0.01) Ia: Hb ¼ 114.5  2.16 Mv; Hmax ¼ 102.3 þ 1.57 Mv; He ¼ 96.9 þ 2.11 Mv (N ¼ 22,577) Ib: Hb ¼ 108.9  1.55 Mv; Hmax ¼ 100.9 þ 1.00 Mv; He ¼ 96.2 þ 1.45 Mv (N ¼ 36,593) III: Hb ¼ 97.5  0.65 Mv; Hmax ¼ 91.9 þ 0.43 Mv; He ¼ 87.1 þ 0.63 Mv (N ¼ 521) F ¼ 0.613  0.0445 Mv r ¼ 1.0  0.2 g/cm3, porosity K ¼ 57% Ia: core: r  2.1 g/cm3 (a1 ¼ 0.010 km, a2 ¼ 2.89/s), fragmentation: low a2 Ia: before core: r w 1.4 g/cm3 (a1 ¼ 0.009 km, a2 ¼ 3.71/s) Ia: after core: r w 1.4 g/cm3 (a1 ¼ 0.009 km, a2 ¼ 3.69/s) Ib: r  2.2 g/cm3 (a1 ¼ 0.006 km, a2 ¼ 5.40/s) e likely Na poor/free III: r w 3.2 g/cm3 (a1 ¼ 0.008 km, a2 ¼ 8.67/s) Max. dynamic pressure rairV2 ¼ 0.030 MPa (0.003e0.067 MPa) Mg0.70 Fe0.72 Na0.038 (N ¼ 94), chondritic, relatively strong O emissions that lower all three numbers From c: w22,000 y, from s: w73,000 y

The date of peak activity is given only if that date significantly differs from the median value for showers with asymmetric activity profiles. The number of meteors observed is the number of triangulated meteors on which the orbital element table is based. The same line also gives the median elevation of the radiant (hr) and the mass of a magnitude zero meteor (see below). The peak ZHR is the Zenith Hourly Rate, a measure of shower activity (rate detected by a single visual observer with standard perception in a clear þ6.5 LM dark sky with the shower radiant near the zenith). Other measures of activity are listed on the same line. The number of

13 meteors on which the orbital element solutions are based is given just under the gray box as “N ¼ .” When values from the literature are not available, an approximate value for the ZHR is calculated from the number of detected meteors NCAMS, from CAMS data alone, according to (scaled to showers with known ZHR values) [60]: 
X  
X  PðMÞvid cM = PðMÞvis cM ZHRwNCAMS = Teff  sU  sinðhr Þ  (2.2) where Teff is the effective observing time (total time a shower is above the horizon for participating stations, multiplied by the fraction of clear sky), sU the dispersion in node (to correct total rate to peak rate), and hr the median radiant elevation of the detected meteors (to correct for geometric dilution from radiant height). The final two factors describe the difference in magnitude-dependent detection efficiency P(M) for video cameras and the standard visual observer [60]. c is the magnitude distribution index. For a visual observer, the fraction of meteors detected above 30 elevation is from 2 magnitude up [60]: P(M) ¼ 0.75, 0.73, 0.70, 0.63, 0.48, 0.32, 0.09, 0.009, 0.001. The video detection efficiencies are shown in the CAMS section in Chapter 3. Comparison to showers with known ZHR values shows an agreement to only about a factor of 3. Years of known outbursts of the meteor shower are listed near the top of the table, sometimes with additional information for each year, such as the peak solar longitude, level of activity, duration of the shower, and magnitude distribution index. The magnitude distribution index (c) describes the ratio of how many meteors are in neighboring magnitude bins of brightness. The observed count (N) per magnitude bin (M) is: NðMÞ ¼ PðMÞcM

(2.3)

The mass distribution index (s) ¼ 1 þ 2.5 log(c). When CAMS-detected rates were high enough to populate the bright 4 to 1 magnitude range, where N(M) w cM, then c could be derived directly. Extrapolation to fainter magnitudes resulted in an observed versus expected number, defining the detection probability P(M). The detection probability is a strong function of apparent entry speed but also depends on the location of the radiant, because different networks have slightly different P(M) for a given shower. P(M) was derived for the major showers and then applied to nearby minor showers. More on this in the “CAMS” section below. Effects from the sky conditions, including the presence of moonlight, e.g. [61], were assumed to have averaged out over many years of observations, but that may not be true for some showers. When available, literature values of c and s are also reported here, with the reference given between brackets. The lightcurve is characterized principally by beginning height, height of maximum brightness, and end height. They depend on meteor magnitude, the brighter meteors are caused by the larger particles and will typically brighten earlier and penetrate deeper. The beginning and end heights of meteors are a function of the meteoroid size, density, and physical properties. The mean lightcurve (of CAMS-detected meteors only) is described by a linear least-squares fit of the beginning height (e.g., Fig. 2.4), maximum brightness height, and end height as a function of the absolute visual magnitude (MV), meaning as seen from a distance of 100 km. The range of peak meteor magnitudes covered is typically from MV ¼ þ3 to 5. The Atlas gives the equation of this linear fit for each component, e.g., in the example above: Hb ¼ 114:5  2:16 Mv ; Hmax ¼ 102:3 þ 1:57 Mv ; He ¼ 96:9 þ 2:11 Mv ðN ¼ 22; 577Þ

14

Methods

The lightcurve shape parameter is defined as [62]: F ¼ ðHmax  Hb Þ = ðHe  Hb Þ

FIG 2.4 Beginning heights of shower 842.

(2.4)

with H the heights when the meteor was first detected, had its maximum brightness, and was last detected. Data are based only on CAMS-detected meteors, so that the limiting magnitude is the same for all showers. Individual meteors in a shower tend to show a wide range of F values. The values given here are derived from the least-square-fitted heights of magnitude zero meteors derived from a least-squares fit of the height versus magnitude diagrams (Fig. 2.4).

The beginning height parameter (kc) and shower beginning height type. The overall distribution of beginning heights follows a relation according to [63,64]: Hb ðkmÞ ¼ kc ðkmÞ  ½2:86  2:00 logðVN ðkm = sÞÞ = 0:0612

(2.5)

which defines the beginning height parameter kc. The equation is written this way because the air mass density rair as a function of height over the full 0e150 km range is approximated by:
 10 lograir g=cm3 ¼  2:86  0:0612 H ðkmÞ (2.6) Values of kc (valid for Mv ¼ 0 meteors) are mostly in the narrow range of 85e103 km. There are three main components (I, II, and III), with occasionally even deeper penetrating trajectory solutions that may be in error (IV). Showers that plot high in a component are labeled “a”, low in a component are “b”. The components are defined in steps of 3 km as: Ia: kc > 103 km I: 103 > kc > 100 Ib: 100 > kc > 97

IIa: 97 > kc > 94 II: 94 > kc > 91 IIb: 91 > kc > 88

III: 88 > kc > 85 IIIb: 85 > kc > 82 IV: 82 > kc

These designations are provided at the start of each list of beginning-, max-, and end heights to clarify where in the diagram of Fig. 2.5 a shower component is placed. A solid meteoroid entering Earth’s atmosphere would exponentially increase in brightness with increasing air density, then lose mass and fade, reaching a peak brightness at about 76% along the luminous trajectory, i.e., F ¼ 0.76. Fragmentation can make the lightcurve more symmetric and lower F to below 0.50. The bulk of type I showers tend to have F-values between 0.65 and 0.75 (Fig. 2.6), just below the nominal 0.76. Long-period comet showers with Vg > 35 km/s tend to have slightly lower F values than the Jupiter-family type with Vg < 35 km/s (Fig. 2.6). All type III showers fall below the dashed line in Fig. 2.6. They light up late, penetrate deep, and have fairly symmetric lightcurves. Such behavior can arise from different mechanisms. Iron particles have a delayed onset due to a higher heat capacity and higher thermal conductivity. They are thought to have F values around 0.3. The pure iron meteoroids that are identified by spectroscopy, however, are not typically associated with meteor showers.

15

FIG 2.5

Distribution of beginning heights, Mv ¼ 0 meteors.

The Type III shower component meteoroids may also have high thermal conductivity, but spectroscopy shows they are composed of sodium-poor or sodium-free heated and partially molten silicates instead. Indeed, the ratio of the number of III versus I/II lightcurves in a shower is in the range 0.05e1 in most cases, but significantly higher for some low-q showers. Those showers are likely affected by heating from sunlight, causing sintering or melting. The Type I, II and II groups correspond to “C,” “B,” and “A” in [64], thought to be respectively fluffy low-density cometary matter, more dense carbaonceous-chondritelike matter, and dense stony-chondritelike matter. Of course, all FIG 2.6 F-value as function of geocentric speed. measured values have a range of measurement uncertainty, so that range limits do not always classify a shower correctly. Meteoroid thermal parameters. The observed values of kc are in a narrow range, suggesting that thermal conductivity and heat capacity correlate with meteoroid density and most meteoroids have similar mineral components. The following thermal parameters are sometimes determined, based on the simple one-dimensional solution of the heat-conductivity

16

Methods

problem during the first part of the meteoroid trajectory where ablation and light production are negligible and the particles are larger than 0.5 mm (stony) or 1e2 mm (iron) [63]:     (2.7) kc ¼ ð1 = 0:0612Þ  log 2TO lrCp b cosðzr Þ = L with T the surface temperature where the meteor first becomes detectable from the onset of rapid ablation or melting of glue (T w 1600 K; range 700e3000 K), l the thermal conductivity (l w 0.5; 0.01e40 W/m/K), Cp the specific heat capacity of the material (Cp w 600; 200e1400 J/kg/K), and L the heat transfer coefficient (L w 1.0; 0.5e100 W/m2/K). Those parameters are specific to the material properties of the meteoroid, and are correlated with the meteoroid density r (r w 1800; 100e7600 kg/m3) [63]. The zenith distance angle of entry (zr w 45 ) and the air-density gradient (b w 1.6; 0.5e3 kg/m3/s) play a role also. End height parameters. Here, we interpret the lightcurve information to give more nuanced density ranges instead. In the same way as Eq. (2.5), a parameter Km and Ke can be defined using Hm and He instead of Hb. A group of type I showers has a narrow range of Ke  87.4, including the Draconids, which suggests these are streams with similar low meteoroid density r w 0.1e0.3 g/cm3. Also, most showers that have both I and III components from their beginning heights still have well-separated differences in end height. However, those who have the I component penetrate into the II regime (Ke < 82) or into the III regime (Ke < 79) are distinct. Similarly, there is a group of Type II showers that has high end heights in the Ke > 82 regime and those that penetrate into the III regime of end heights. Remarks are added when that is the case. The mass of a magnitude 0 meteor can be inferred from the meteor peak brightness and duration, and its speed, assuming a certain fraction of the meteoroid’s kinetic energy goes into the wavelength range of light detected by the cameras. That fraction is called the luminous efficiency. Recent studies show no clear dependence of luminous efficiency on entry speed or mass [65,66] and we have adopted here a constant value of 1% for the 400e800 nm range of low-light video cameras. That value could be as high as 9% or as low as 0.1% and depends on meteoroid composition (different for iron meteoroids compared to stony meteoroids). The mass given here (in kg) is calculated simply from:   mðMv ¼ 0Þ ¼ 3:67:1011  Dt  Dl  4pR2 = 0:5  s  VN 2 (2.8) with the irradiance of a zero magnitude meteor 3.67  1011 W/m2/nm, duration Dt(s) ¼ 5.54 * VN (km)0.73, Dl ¼ 380 nm, and R ¼ 100 km the standard distance for absolute magnitude. Meteoroid density. The meteoroid density (r) can be derived from its deceleration early in the trajectory, if we ignore fragmentation. CAMS measures the deceleration by fitting a timedependent velocity profile to the meteor’s trajectory, defined by two parameters a1 and a2, so that [67]: V ¼ VN þ a1 a1 ð1  expða2 tÞÞ

(2.9)

with V (km/s) the instantaneous speed, and VN the apparent beginning speed. Here a1 has units of km and a2 units of s1. The acceleration at the beginning of the trajectory is to first order dV/dt ¼ a1 a22. The equation of motion of a meteoroid entering an atmosphere [63]: dV=dt ¼  Cd ðA = 2mÞrair V2

(2.10)

17 with Cd the drag coefficient, A the surface area of the particle, and its mass m. Most important here is the exponentially increasing air density (rair) with decreasing height. Here, it is important to calculate the actual air density as best approximated in the 70e120 km range of height: 10 log rair (g/cm3) ¼ 1.93e0.0729 H (km) (according to the COSPAR International Reference Atmosphere). We calculated beginning heights for meteors of absolute magnitude MV ¼ 0. Best agreement with published lightcurve models that include fragmentation (Table 2.2) is obtained if the meteoroid radius does not introduce another VN-dependent term. If, the luminous efficiency does not depend on speed, and taking into account that the mass of a zero magnitude meteor according to Eq. (2.18) is found proportional to m w V2.73 (including Dt N dependence on VN), then densities calculated should be multiplied by an additional factor 3 of Vþ2.73/3 ¼ Vþ0.91 N N . In that case, the meteoroid density is (with VN in km/s and r in g/cm ):     r w VN þ0:91  rair VN 2 = a1 a2 2 (2.11) The density scale was calibrated by assuming that the highest densities are that of silicates (r w 3.5 g/cm3). The resulting Orionid and Geminid densities are close to the 0.4 and 1.2 g/cm3 found by recent high-resolution modeling [68]. With that, we confirm a trend found in recent years [69] that long-period comet showers tend to have low meteoroid densities TABLE 2.2 Densities from literature (with r ¼ 0.2e1.8 g/cm3, while Jupiter-family comet s w VN) and as calculated here. showers tend to have intermediate meteoroid denrlit. rcal. VN sities of 0.4e2.8 g/cm3. Put in context, the density 3 3 IAU Shower (km/s) (g/cm ) (g/cm ) of particles around the nucleus of Jupiter-family comet 67P/Churyumov-Gerasimenko were in 9 DRA 23.6 0.3  0.1 0.28 the range 0.8e3.0 g/cm3 [70]. Primitive CI and 13 LEO 71.2 0.6  0.2 0.33 CM type carbonaceous chondrite meteorites 8 ORI 67.0 0.9  0.2 0.41 7 PER 59.9 1.0  0.2 0.52 have densities r ¼ 1.8e2.8 g/cm3, while stony or1 CAP 25.3 1.4  0.2 1.08 dinary chondrites have densities r ¼ 3.2e3.9 g/ 2 STA 30.0 1.8  0.2 1.45 cm3. Most meteoroids are loosely stacked collec10 QUA 41.9 2.1  0.6 1.21 tions of individual grains, so that the meteoroid 5 SDA 42.1 3.5  0.3 1.39 bulk density is lower than the meteoroid grain 4 GEM 35.6 3.6  0.3 1.30 density. Bulk density is what is determined here. The porosity (fraction of empty space) is given with the letter K. Because of the large scatter in the deceleration parameters, methods based on Eq. (2.11) rely on measuring the decelerations of a large group of meteoroids. We find that reliable median values for a1 and a2 require N w 1000 for 16% uncertainty in density, N w 100 for 50%, while useable numbers (error in density 50%e100%) are sometimes obtained for N > 50. The method assumes little fragmentation. If fragmentation is dominant, the deceleration parameter a2 will be low and the calculated densities too high. Indeed, low values of a2 are found when there are other signs of fragmentation, such as high beginning heights, early release of sodium relative to magnesium, and wake. Notes are made when that is the case. Another group of solutions differ by giving calculated densities that are too low. This could point to meteoroids of unusual composition or with unusual thermal properties so that they start illumination higher in the atmosphere. The Southern d-Aquariids, for example, have a low perihelion distance (prone to heating), for which we have 1.4 g/cm3 but various meteor lightcurve models (with s w VN) found 2.4e4.1 g/cm3. Strength: The PE coefficient is a description of meteoroid strength based on the end height rather than the beginning height. [71] defined the value of PE as a function of air density at the fireball end height, rair, the initial photometric mass, mN (with luminous efficiency according

18

Methods

to [71]), initial apparent velocity, VN, and zenith distance of the radiant at the fireball beginning, z ¼ 90  hr: PE ¼ logðrair Þ þ A logðmN Þ þ B logðVN Þ þ C logðcosðzÞÞ

(2.12)

with fireballs grouped in four classes I (strongest, deeply penetrating), II, IIIA, and IIIB (weakest). Here, the Roman numerals describing end height are in opposite direction with height than those we use to characterize the beginning height above. Spectroscopy data are derived from the observed line intensity ratios (after correction for instrumental responsivity and atmospheric extinction). For example, Na/Mg and Fe/Mg give the meteor plasma’s relative abundance ratio of sodium versus magnesium atoms and iron versus magnesium atoms, respectively. Na/Mg is derived from the 589-nm wavelength Na line doublet (NaeI multiplet 1) and the 518-nm Mg line triplet (MgeI multiplet 2), respectively. The line ratio Fe/Mg is derived from the intensity of the 527e550 nm lines of Fe (FeeI multiplet 15). Care is taken to remove underlying continuum emission and molecular (First Positive band of N2) emissions and remove the contribution of FeeI line emission under the Mg lines. FIG 2.7 Mg/O line ratio versus entry speed. The plasma excitation temperature can be derived from the numerous iron lines in the 482e500 (FeeI multiplet 318) and 527e550 nm range (FeeI multiplet 15) and is found to remain nearly constant over the VN ¼ 11e72 km/s range, usually at T ¼ 4500 K for the warm wake plasma and T w 10,000 K for the hot shockerelated component [72]. This means that line intensity is proportional to abundance. The oxygen line intensities at 615 and 777 nm relative to the N2 First Positive band strength also do not significantly depend on VN. These air plasma emissions are quenched by the higher air density at lower elevations, as a result of which they are weak or absent below VN ¼ 20 km/s. Normal “chondritic” means that those line ratios are indicative of normal early-solar system abundance ratios. Based on the general trend of intensity ratios with velocity (e.g., Fig. 2.7), chondritic values of line ratios, with VN in km/s for CAMSS data can be expressed as: Mg = O ¼ 0:10 þ 4:3 expð0:06 VN Þ

(2.13a)

Fe = O ¼ 0:19 þ 15:2 expð0:11 VN Þ

(2.13b)

Na = O ¼ 0:077 þ 110 expð0:17 VN Þ

(2.13c)

600 nm continuum = O ¼ 0:004 þ 2:0 expð0:18 VN Þ

(2.13d)

The early solar system chondritic abundances relative to Mg are: Mg ¼ 1.00, Fe ¼ 0.85, and Na ¼ 0.056 [73]. In this Atlas, the plasma composition is Mg/O over the expression in Eq. (2.13a), multiplied by these abundances, so that a number Mg1.0 Fe0.85 Na0.056 means a

19 chondritic composition. In the same way, the relative strength of the continuum at 600 nm for low-speed showers can be given, with “dust1.0” being the typical continuum/O emission. After accounting for the velocity-dependence of Na emissions (Eq. 2.13c), meteors of type II and III with speed VN > 35 km/s are mostly “Na-poor” or “Na-free” where “poor” and “free” indicate a (non-zero) range of Na content [74,75]. Ia meteors with speed VN > 50 km/s are often Fe-poor [74]. Na and Fe are in minerals that melt easier than the core iron-magnesium silicates, and a lack could point to heating at the surface of the parent body or while in space. In a few cases, Na and Fe abundances correlate with peak magnitude. In those cases, we give values relevant to Mv ¼ 0 meteors. Slow V < 35 km/s type III meteors are often irons [74], but Fe particles (N¼19) in CAMSS data so far reduced are all sporadic meteors on asteroidal orbits. The age of a meteoroid stream follows from how long it takes to spread out as much as observed. That gets complicated when close encounters to planets or mean motion resonances are involved. In those cases, we rely on case studies published in the literature. Other streams should disperse in a more predictable manner with age. About half of the 500+ showers in this Atlas originated from Long Period comets. Those streams, dense enough to be detected as meteor showers on Earth, have parents with orbital periods in the range 250 to 4,000 y [76]. Many retrograde streams (inclination > 90 ) show a drift in u and P along Earth’s orbit that is a strong function of the inclination (Fig. 2.8). This suggests, they have a normal rate of precession (or regression, if the orbit is prograde), unaffected by close encounters or resonances.

FIG 2.8

Drift in P (and u) as function of inclination.

FIG 2.9 c versus the combined dispersion in U, u and i for the band of long-period comets in Fig. 2.8 (•) and other LPC with i > 90 (+).

We calculated the dispersion of a number of streams using a 15th order numerical integrator code, run in Cartesian coordinates, with gravitation, solar radiation and wind pressure, and Poynting-Robertson effect included [77]. Starting from ejection, the motion of w250 meteoroids with radii in the range of observed meteoroids were followed for 50,000 to 200,000 years. For each return to Earth orbit, the spread in inclination, argument of perihelion and node was calculated for meteoroids that passed within 0.02 AU from Earth orbit during 200-y intervals. It was found that the spreading of the meteoroids was due to two processes: a random kick every time the meteoroid passed through the inner solar system, and a gradual continuous change due to precession/regression of the Node (and less so of inclination) at a rate inversely proportional to the orbital period. The random kicks caused spreading proportional

20

Methods

to the square root of the number of orbits, while the precession further increased the spread in proportion to the number of orbits. The lower q, the stronger the kicks. At the same time, the meteoroid’s orbital period tended to disperse, with meteoroids returning most often having the shorter periods. The net effect was a linear increase of the dispersions in inclination (si), argument of perihelion (su) and Node (sU) with age, after a brief initial rapid exponential increase, until the stream evolves away from Earth’s orbit. We chose to define a combined dispersion (s) and an empirical age as follows, with dv = 180  invcos{sin(l þ lo) cos(b)}, calibrated against the few models of long-period comet meteoroid streams in the literature (see references in each shower section): ffi qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi  2 2 2 Age-sðyÞ w 12; 000 q ðsl Þ þ ðsuÞ þ ðsU sinðdv ÞÞ (2.14) where dv is the angle between the apex and the vector Vg (correcting the dispersion in node for the angle in which the Earth travels through the stream) and q the perihelion distance. Both si and su were corrected for their mean observed measurement error. Our own calculations showed ages systematically a factor of two older, but are otherwise in agreement to within a factor of two. We adopted the younger ages according to Eq. 2.14 as “From s:”, and give our results from numerical simulations separately as “From model:”. We also identified an empirical age based on the magnitude distribution index c, after noticing that c increased with s (Fig. 2.9). In this case, we assumed a common starting point, which may or may not be true for all streams, and set it at the lowest measured values of c ¼ 1.85, the value where there is an equal combined cross sectional area per magnitude bin: Age-c ðyÞ w 66; 000 q ðc  1:85Þ

(2.15)

We found the empirical relations 2.14 and 2.15 hold true to first order also for other longperiod comets with i > 90 (TJ < 0.65). We then noticed that a similar Age-s relationship holds true for Mellish-type showers (0.65 < TJ < 2, i < 90 ) not affected by resonances and close encounters, but with a different scaling factor): ffi qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi  2 2 2 Age-s ðyÞ w 6000 q (2.16) ðsl Þ þ ðsuÞ þ ðsU sinðdv ÞÞ For a given dispersion, the stream is only half as old, because Mellish-type comets tend to have shorter orbital periods. The relationship with the magnitude distribution index c was not well defined and remains only tentatively described by: Age-c ðyÞ w 42; 000 q ðc  1:85Þ

(2.17)

For a given magnitude distribution index, the stream is also only about half as old. Precession is responsible for the July tail (background) of the Perseid shower, while the random kicks are responsible for the width of the main maximum. We noticed that the Perseid maximum has sU < su, while the background has sU w su. As a result, remarks are added if 3 * sU sin(dv) < su, suggesting that Earth passed through the core area of the stream (beware: not necessary through the center of a dust trail). The short-period Taurid showers also mostly stay away from close encounters with Jupiter. The age estimates from modeling [78] were compared to the observed magnitude distribution index of each component, and the following empirical relation was found: Age-c ðyÞ w 37; 500 q ðc  1:85Þ

(2.18)

21 Source:

109P/Swift-Tuttle

Orbital elements (J2000.0) Epoch 1995-Oct-10.0 TDB

a (AU) 26.1

q (AU) 0.960

e 0.963

i ( ) 113.5

u ( ) 153.0

U ( ) 139.4

P ( ) 292.4

Parent Body Source: If the source of the meteoroid stream is known, a gray box provides the orbital elements of the comet or primitive asteroid as provided by the JPL/CNEOS website. Some uncertain parent body identifications are also given, labeled “euncertain”. The orbital elements given are only meant as a guide, because there are sometimes differences in the orbital evolution of the parent body and that of the meteoroid stream as detected in Earth’s path. The parent body orbit is that measured close to the current Epoch and will have evolved since the time of particle ejection. No attempt was made to correct for this. The meteoroid orbits will also have evolved. FIG 2.10 Overview of reported showers. Nearly half of the video-detected showers originated from long-period comets with orbital periods between 250 and 4000 y [76], but the meteoroids detected at Earth are the ones that return most frequently. Those now have orbital periods of around 20 to 1000 y and inclinations between 20 and 180 (Fig. 2.10). Most showers detected uniquely by radar are the short-period showers from the helion source (most with inclinations < 20 ) and from the toroidal source with inclinations between 20 and 90 . References: [1] Whipple F. L. (1954) AJ 59, 201e217; [2] Katasev L. A. (1964) Photographic Methods in Meteor Astronomy. Jerusalem: IPST, 114 pp.; [3] Babadzhanov P. B., Kramer E. N. (1967) SCoA 11, 67e79; [4] Lindblad B. A., et al. (2003) EMP 93, 249e260; [5] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [6] Hawkins G. S., Southworth R. B. (1961) SCoA 4, 85e96; [7] McCrosky R. E., Posen A. (1961) SCoA 4, 15e84; [8] Ceplecha Z., et al. (1964) BAC 15, 144e155; [9] Ceplecha Z. (1957) BAC 8, 51e61; [10] Oberst J., et al. (1998) MAPS 33, 49e56; [11] Lindblad B. A. (1990) Documentation of Meteor Data available at the IAU Meteor Data Center. Lund: Lund Observatory, 31 pp; [12] McCrosky R. E., et al. (1978) Meteoritika 37, 44e59; [13] Halliday I., Griffin A. A., Blackwell A. T. (1996) MAPS 31, 185e217; [14] Halliday I. (1988) Icarus 76, 279e294; [15] Campbell-Brown M. D., Hildebrand A. (2004) EMP 95, 489e499; [16] Betlem H., et al. (1998) AA Suppl. 128, 179e185; [17] Lindblad B. A. (1987) Contr. Astron. Inst. Czechoslovak. Acad. Sci. 67, 201e204; [18] Tedesco E. F., Harvey G. A. (1976) AJ 81, 1010e1013; [19] Cooke W. J., Moser D. E. (2012) Proc. IMC 2012, Sibiu, Mechelen: IMO, p. 9e12; [20] Colas F., et al. (2020) AA 644, A53eA76; [21] Davies J. G., Gill J. C. (1960) MNRAS 121, 437e462; [22] Lebedinets V. N. (1968) In: IAU Symposium 33: Physics and Dynamics of Meteors. Eds.: Kresak L., Millman P. M., Dordrecht: D. Reidel, pp. 241e264; [23] Nilsson C. S. (1964) AUJP 17, 205e256; [24] Verniani F. (1973) JGR 78, 8429e8462; [25] Sekanina Z. (1973) Icarus 18, 253e284; [26] Lebedinets V. N., et al. (1981) Radar Investigations of Meteors in Obninsk: Catalog of Orbits. SeptembereDecember 1967. Moscow: Interdepartmental Geophysical Committee at the Presidium of the USSR Academy of Sciences;

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Methods

[27] Lebedinets V. N., et al. (1982) Radar Exploration of Meteors in Obninsk: Catalog of Orbits, JanuaryeAugust 1968. Moskow: Interdepartmental Geophysical Committee at the Presidium of the USSR Academy of Sciences; [28] Andrianov N. S., et al. (1968) In: IAU Symposium 33: Physics and Dynamics of Meteors. Eds, Kresak L., Millman P. M., Dordrecht: Reidel, pp. 14e26; [29] Andrianov N. S., et al. (1970) MNRAS 148, 227e237; [30] Gartrell G., Elford W. G. (1975) AUJP 28, 591e620; [31] Sekanina Z. (1976) Icarus 27, 265e321; [32] Fedynski V. V. (1975) Meteor Orbits and Rates from Equatorial Survey, Vol. 1. Materials of the World Data Center B. Moscow: Soviet Geophysical Committee of the Academy of Sciences of the USSR; [33] Fedynski V. V. (1977) Meteor Orbits and Rates from Equatorial Survey, Vol. 2. Materials of the World Data Center B. Moscow: Soviet Geophysical Committee of the Academy of Sciences of the USSR; [34] Kashcheev B. L., Tkachuk A. A. (1980) Results of radar observations of faint meteors: Catalog of orbits of meteors up to +12m. Moscow: Materials of the World Data Center B; [35] Baggaley W. J., et al. (1994) QJRAS 35, 293e320; [36] Baggaley W. J., Bennett R. G. T., Steel D. I., Taylor A. D. (1994) QJRAS 35, 293e320; [37] Galligan D. P. Baggaley W. J. (2005) MNRAS 359, 551e560; [38] Brown P., et al. (2001) ESA SP495, 469e474; [39] Chau J. L., et al. (2007) Icarus, 188, 162e174; [40] Brown P., et al. (2008) Icarus 195, 317e339; [41] Brown P., et al. (2010) Icarus 207, 66e81; [42] Nakamura T., et al. (2012) 40th COSPAR Scientific Assembly. Held 2e10 Aug 2014, Moscow, Russia. Abstract id. C0.3-7-14; [43] Froncisz M., et al. (2020) PSS 190, article id. 104980 (74 pp.); [44] Schult C., et al. (2018) Icarus 309, 177e186; [45] Janches D., et al. (2015) ApJ 809, 36e52; [46] Bruzzone J. S., et al. (2020) PSS 188, article id. 104936; [47] Sarma T., Jones J. (1985) BAC 36, 9e24; [48] Ueda M., et al. (2001) In: Proceedings of the Meteoroids 2001 Conference, Ed.: B. Warmbein, Kiruna: Swedish Institute of Space Physics, pp. 325e330 (ESA SP 495, 325e330); [49] Lindblad B. A. (1999) In: Meteoroids 1998. Eds.: Baggaley W. J., Porubcan V.. Bratislava: Astron. Inst. of the Slovak Acad. of Sci., p. 274e282; [50] Lindblad B. A. (1991) In: IAU Colloq. 126: Origin and Evolution of Interplanetary Dust. Vol. 173. Eds.: Levasseur-Regourd A. C., Hasegawa H., Dordrecht: Kluwer Academic Publishers, p. 311e314; [51] Koten P., et al. (2004) AA 428, 683e690; [52] Kornos L., et al. (2013) Proceedings of the IMC. Poznan, Poland, 22-25 August 2013. Eds.: Gyssens M., Roggemans P., Zoladek P., Mechelen: International Meteor Organization, pp. 23e25; [53] Kornos L., et al. (2018) In: Proceedings of the IMC, Petnica, Serbia, 21e24 Sept. 2017. Eds. Gyssens M., Rault J.-L., Mechelen: IMO, pp. 46e49; [54] Kanamori T. (2009) JIMO 37, 55e62; [55] Jenniskens P., et al. (2011) Icarus 216, 40e61; [56] Korlevic K., et al. (2013) JIMO 41, 48e51; [57] Vida D., et al. (2021) MNRAS 506, 5046e5074 (https://globalmeteornetwork.org/data/); [58] Hawkins G. S. (1963) SCoA 7, 53e62; [59] Jenniskens P., et al. (2016) Icarus 266, 384e409; [60] Jenniskens P. (1994) AA 287, 990e1013; [61] Molau S., et al. (2015) JIMO 43, 181e187; [62] Jacchia L. G., et al. (1967) SCoA 10, 1e139; [63] Levin B. J. (1956) Physical Theory of Meteors and the Meteor Matter in the Solar System. Moscow: AN SSSR; [64] Ceplecha Z. (1967) SCoA 11, 35e60; [65] Drolshagen E., et al. (2021) AA 650, A159eA176; [66] Ott T., et al. (2021) JIMO 49, 152e157; [67] Whipple F. L., Jacchia L. G. (1957) SCoA 1, 183e206; [68] Buccongello N., et al. (2023) ACM 2023, LPI Contrib. No. 2851, Abstract 2464; [69] Kikwaya Eluo J.-B. (2011) Bulk Density of Small Meteoroids. PhD Thesis, London: UWO, p. 223e227; [70] Rotundi A., et al. (2015) Science 347, article id. aaa3905; [71] Ceplecha Z., McCrosky R. E. (1976) JGR 81, 6257e6275; [72] Jenniskens P., Mandell A. M. (2004) Astrobiology 4, 123e134; [73] Lodders K. (2019) Solar System Abundances (arXiv:1912.00844); [74] Vojácek V., et al. (2019) AA 621, A68eA89; [75] Borovicka J., et al. (2005) Icarus 174, 15e30; [76] Jenniskens P., et al. (2021) Icarus 365, article id.114469; [77] Pilorz S., Jenniskens P., Vaubaillon J. (2023) Asteroids, Comets, Meteors 2023. Flagstaff: USRA, Abstract id. 2484; [78] Egal A., et al. (2022) MNRAS 515, 2800e2821.

C H A P T E R

3

Meteoroid orbit surveys

Atlas of Earth's Meteor Showers https://doi.org/10.1016/B978-0-323-88447-1.00009-0

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© 2024 Elsevier Inc. All rights reserved.

24

Meteoroid orbit surveys

CAMS: The global Cameras for Allsky Meteor Surveillance network Contributed by: P. Jenniskens, P. Gural, D. Samuels, S. Rau, J. Albers, S. Ganju, J. Collison, D. Holman, B. Haberman, T. Abott, W. J. Baggaley, T. Beck, W. Cooney, T. Cooper, M. de Cicco, T. Hanke, S. Heathcote, A. Howell, E. Jehin, C. Johannink, M. Breukers, L. Juneau, N. Moskovitz, M. Odeh, M. Towner, and O. Unsalan

FIG 3.1

Equipment for CAMS Chile network.

What is CAMS? The Cameras for Allsky Meteor Surveillance (CAMS) project deploys globally over 500 low-light video cameras in 12 networks for the triangulation of meteors (Table 3.1). The networks cover the night-time skies in both the northern and southern hemispheres. The CAMS project scaled up the triangulation of meteoroid orbits using low-light video cameras in order to map both major and minor meteor showers and aimed to confirm previously reported meteor showers in the IAU Working List of Meteor Showers [1].

TABLE 3.1 CAMS networks, with # the network number (as of December 31, 2021). #

Network

Country

Coordinator

# Orbits

Years

1 2 3

CAMS California CAMS Florida CAMS BeNeLux

CA, USA FL, USA BeNeLux

602,233 95,648 274,062

2010e2021 2014e2021 2014e2021

4 5 6 7 8 9 10 14 15 16 17 19 20

CAMS Mid Atlantic CAMS New Zealand Lowell Observatory CAMS UAE Astronomical Camera Network CAMS South Africa CAMS EXOSS CAMS Northern California CAMS Arkansas CAMS Australia CAMS Chile CAMS Namibia CAMS Texas CAMS Turkey

MD and VA, USA New Zealand AZ, USA UAE South Africa Brazil CA, USA AK, USA Australia Chile Namibia TX, USA Turkey

P. Jenniskens A. Howell C. Johannink/ M. Breukers P. Gural W. J. Baggaley N. Moskovitz M. Odeh T. Cooper M. de Cicco T. Beck L. Juneau M. Towner S. Heathcote/E. Jehin T. Hanke W. Cooney O. Unsalan

8768 98,645 249,511 84,650 30,378 1235 11,777 43,707 116,031 162,684 212,113 18,162 1308

2014e2021 2014e2021 2015e2021 2015e2021 2017e2021 2017e2021 2017e2021 2018e2021 2019e2021 2019e2021 2019e2021 2020e2021 2021e2021

Brief history: Motivated by the difficulty to assemble a comprehensive table of known meteor showers from the published literature for a book written in 2006 [2], CAMS (Fig. 3.1) was proposed as a project to NASA in the same year. Low-light video camera technology had reached a low enough price point to make cost-effective a multi-camera “fly’seye” approach to all-sky coverage. First light was achieved in October of 2010, where the principal investigator was P. Jenniskens and the end-to-end processing pipeline of software modules from image capture to meteor orbit estimation were written from the ground up by P. Gural. Initially those modules were installed on commercial video surveillance servers, but later on dedicated Windows-based PCs. D. Samuels, S. Rau, and others developed scripts to operate those PCs autonomously for both the primary deployed multi-camera systems and for participating amateur astronomers, and they also helped maintain the network over the

25 years [8]. A lower cost approach was developed by J. Wray in 2016, author of [3], who used Sony Effio-E cameras instead of the Watec Wat902H2 Ultimate cameras. Those techniques were subsequently used in LO-CAMS and other networks. In 2017, the submission of data and verification of triangulations were automated as part of NASA’s Frontier Development Laboratory program, notably with the help of J. Collison and S. Ganju. This effort also enabled further expansion of the network to southern hemisphere locations in 2019 to obtain a more global coverage of shower activity. Results presented here include data gathered up to May 31, 2022. Since late 2017, the daily results of radiant positions and speed are posted online in near-real time at http://cams.seti.org/FDL/, and more recently at https:// meteorshowers.seti.org. Technical details: The main CAMS networks deploy 16e20 cameras each at three or more stations, each station covering the sky above about 30
elevation. If a significant fraction of the meteor trajectory is below 30
elevation, the result is less precise and not included. Smaller networks provide a partial sky coverage with less camera pairs. The Watec Wat902H2 Ultimate low-light video cameras are deployed with two lens options: 12 mm/ f1.2 pointed at low 40
elevations and 8 mm/f1.3 pointed at high 61
elevation. The sensor is an enhanced Ex-View HAD II, 1/2 -inch format CCD typically digitized to 640  480 pixels, if operated in analog NTSC format, or with 752  480 pixels when operated in PAL. The angular resolution of the cameras is 2.80 /pixel. The 30 Hz video is interlaced, producing meteor positions at a 60 Hz frequency. The alternative camera, the Sony Effio-E, is based on the 1/3 inch Sony Ex-View CCD chip. When equipped with 8-mm/f1.0 lenses, the field of view and the star limiting magnitude are close to that of the Watec cameras (20
 30
and þ5.4 limiting magnitude). The CAMS meteor detection software at each station was initially based on MeteorScan [4] and was later improved to speed up the detection process by 40, using a cluster and tracking algorithm, and to better the trajectory calculation [5]. The astrometry is calibrated against background stars using a cubic polynomial warp fit, automatically performed for each camera once per night, with a negligible night-to-night variation in the center pointing of the camera field over several nights. This nightly calibration also includes a photometric fit between sum pixel brightness and magnitude. The normalized photometric passband for the camera and lens system is about 0.2, 0.8, 0.8, and 0.2 for the 400e500, 500e600, 600e700, and 700e800 nm wavelength ranges, respectively. Photometry is corrected for lens vignetting. Data are compared to the visual magnitude of stars. In visual verifications of trajectory solutions, the light curves usually align well. From this, the photometric uncertainty is about 0.3 magnitude. The atmospheric trajectory and the Keplerian orbital parameters are computed by triangulating meteors seen from two or more contributing stations. Most networks submit their metric data of detected tracks (time, astrometry, and photometry) to the SETI Institute, where a central computer performs the triangulations and posts the nightly results. The distributed CAMS BeNeLux and CAMS Mid-Atlantic networks do their own central processing of triangulations and report final orbits to the SETI Institute. Up to the end of 2016 (including the second release of CAMS data), all triangulations were visually inspected and validated. In 2017, deep learning techniques using a convolutional neural network were shown to reliably sort out false detections from true meteors, but that technique is pending final implementation, which leaves a higher fraction of false detections in the automated processed results [6,7]. While nearly all meteors brighter than þ0 magnitude are detected, most faint meteors are not (Fig. 3.2). This is mainly because the contributing stations in a triangulation are often at different distances from the meteor and meteors are fainter when further away. Also, fast meteors tend to move rapidly over the sensor and are less efficiently detected. Meteors slower than 20 km/s are also more easily missed. Finally, the detection efficiency of a given shower depends on whether it can be detected by southern hemisphere stations, which have newer cameras on average that are located under darker skies. The efficiency curves of Fig. 3.2 were derived empirically from the observed magnitude distribution of strong showers, by

26

Meteoroid orbit surveys

exponentially extrapolating the observed bright magnitude distribution. In this way, the average curves of Fig. 3.2 were derived for slow antapex showers with VN ¼ 11e20 km/s, N. and S. anthelion and helion showers with VN ¼ 20e30 km/s, toroidal showers with VN ¼ 30e45 km/s near the ecliptic and at high elevation, and N. and S. apex showers with VN ¼ 45e72 km/s, for radiants in the northern and southern hemisphere separately. If a minor shower had a radiant near one of the calibrated showers, then that efficiency curve was used. Error bars for the main output parameters are calculated for each meteor. The median FIG 3.2 CAMS detection efficiency for different meteor 1-s accuracy of the apparent radiant positions are 0.16
in R.A. cos(Decl.), 0.15
brightness and speed VN. in Decl., and 0.23 km/s in apparent entry speed. Table 3.2 also shows how that translates to median errors and standard errors for the orbital elements. TABLE 3.2

lo (
) RA. (
) Dec. (
) VN (km/s) q (AU) e i (
) u (
) U (
) P (
)

Errors per meteor and standard errors for Perseids (PER), from N ¼ 60,000 meteors, and June iota Pegasids (JIP) from N ¼ 100. s

PER e std. err.

JIP e std. err.

0.00005 0.16 0.15 0.23 0.0028 0.026 0.50 0.77 0.0003 0.77

e 0.003 0.002 0.003 0.00003 0.0002 0.005 0.009 4E-6 0.01

e 0.03 0.03 0.08 0.0009 0.003 0.05 0.08 0.00004 0.25

Acknowledgments: CAMS is made possible thanks to the effort and time dedicated to building and maintaining the networks by network and station operators. CAMS was initiated by a grant from NASA and has been maintained over the years with ongoing support from NASA. References: [1] Jenniskens P., Gural P. S., Dynneson, L., Grigsby, B. J., Newman, K. E., Borden, M., Koop, M., and Holman, D. (2011) Icarus 216, 40e61; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, Table 7; [3] Wray J. D. (1967) The Computation of Orbits of Doubly Photographed Meteors. Albuquerque: University of New Mexico Press, 211 pp.; [4] Gural P. S. (2008) EMP 120, 269e275; [5] Gural P. S. (2012) MAPS 47, 1405e1418; [6] de Cicco M., et al. (2018) Proceedings International Meteor Conference 2017, Petnica, Serbia. Eds.: Gyssens, M. Rault J.-L., Mechelen: International Meteor Organization, p. 65e70; [7] Gural P. S. (2019) Proceedings International Meteor Conference 2018, Bollmannsruh, Germany, 03e06 October 2019. Eds.: Pajer U., et al., Mechelen: IMO, pp. 171; [8] Samuels D. (2021) eMeteorNews 6, 415e428.

27

CAMSS: The CAMS spectrograph Contributed by: P. Jenniskens, P. Gural, J. Albers, A. Berdue, and C. Pavao What is CAMSS? A spectrograph was built to complement the CAMS meteor triangulations [1,2] with the goal to scale-up the measurement of main-element compositions of meteors, in particular, the measurement of Na/Mg and Fe/Mg ratios. The spectrograph uses the same cameras, but they are equipped with a dispersive element to create 390e900 nm spectra of bright meteors for which CAMS provided a trajectory and orbit. Brief history: The development of this spectrograph followed soon after the first CAMS FIG 3.3 The CAMS spectrograph. network was established. The layout of the 16 cameras was optimized for the coverage of spectra in first order. The camera box went into operation at a central location in Sunnyvale, California, on March 12, 2013, and has remained at that location since. Software tools were developed to prescreen the recorded video segments for meteors, derive the responsivity and telluric extinction from the recorded spectra of stars, and to extract the line intensities from the measured spectra based on the CAMS-measured trajectories. In 2022, scripts and deep learning tools were added to automate the prescreen and data handling. Technical details: Fig. 3.3 shows the CAMSS camera enclosure. Six cameras are pointed at 67.5
elevation, 10 cameras at a low 45
elevation. A BK7 optical window (Edmund Scientific) with a MgF2 antireflection coating is placed 45
from boresight, because the first spectral order light typically falls onto the camera at a high 45
angle. The grating holder provides a clear field of view for light falling onto the grating for entry angles of up to 65
in the first-order dispersion direction. Sixteen Watec Wat902H2 Ultimate CCD cameras were equipped with Pentax 12.0 mm f1.2 lenses for a 22
 30
field of view and 29.97 frames per second NTSCFIG 3.4 Normalized instrumental responsivity from type recording with 640  480 pixel video output dimensions. The lenses are achrostars (thick) and lab measurements (thin). matic over the range 410e900 nm wavelength, with some responsivity but progressively blurry imaging in the range 390e410 nm. Each camera was equipped with a 1  1 cm-sized Ibsen Photonics FSTG-VIS1379-911 grating, placed at an angle 25
from boresight (grating tilt), covering the clear aperture of the lens. The gratings have 1379 lines/mm at 200 micron groove depth etched in fused silica glass. This provides a dispersion of 1.1 nm/pixel. The instrumental responsivity curve as measured against background stars is shown in Fig. 3.4. Meteors brighter than þ0.2 peak magnitude produce usable spectra.

28

Meteoroid orbit surveys

FIG 3.5

Representative CAMSS spectra of iron meteoroids (left), slow V < 30 km/s chondritic meteors (middle), and fast sodium-poor meteors (right), before correction for instrument responsivity and extinction.

After calibrating the camera’s field of view, the spectra are extracted by stepping through the list of CAMS-detected trajectories in the CAMS California network, and calculating the expected position of each spectrum on the CCD sensor. The rotation, yaw and tilt of the grating, as well as the number of grooves per millimeter can be adjusted to match the predicted position to the observed position of the strong emission lines of Mg, Na, and O. Once a satisfactory fit is obtained, time differences between CAMS and CAMSS are corrected by selecting the altitude that best matches a given video frame. The spectra are extracted by integrating the pixel intensity along the direction of the emission lines as it moves FIG 3.6 Na/Mg ratio versus entry speed. over the sensor, on a frame-by-frame basis. These raw spectra are then wavelength-aligned further, when needed, and integrated along the meteor path (Fig. 3.5). The integrated line intensities of Mg, Na, Fe, K, and O lines are extracted after removing the underlaying background continuum and First Positive band of N2 (Fig. 3.5). The line intensities are corrected for telluric extinction and instrument responsivity (Fig. 3.4). Here, we present results from spectra of 1005 meteors recorded during March 24, 2013 to August 31, 2014. Four hundred and sixty-two of these were assigned to showers. Fig. 3.6 shows the Na/Mg ratios of the combined dataset. The accuracy in the line ratios (w20%) is mostly determined by how well the background N2 band emission and instrumental responsivity are known. Most spread is real, e.g., the Geminids show a wide Mv-dependent range of values. Acknowledgments: CAMSS was made possible thanks to a grant from NASA and has been operated and maintained by J. Albers and D. Gilbert in Sunnyvale. References: [1] Jenniskens P., Gural P. S., Dynneson, L., Grigsby, B. J., Newman, K. E., Borden, M., Koop, M., and Holman D. (2011) Icarus 216, 40e61; [2] Jenniskens P., Gural P., Berdeu A. (2014) In: Meteoroids 2013. Ed.: Jopek T. J. et al., Poznan: A. M. Univ. Press, p. 117e124.

29

SonotaCo: The SonotaCo Network Contributed by: T. Kanamori, T. Masuzawa, T. Sekiguchi, H. Inoue, M. Ueda, H. Yamakawa, T. Miyoshi, T. Kamimura, Y. Fujiwara, Mr. Ada, K. Maeda, K. Yoneguchi, N. Saito, H. Muroichi, Y. Shiba, S. Uehara, J. Yokomichi, J. Nakai, S. Okamoto, C. Shimada, H. Kawakami, and T. Nakamura What is the SonotaCo Network? The SonotaCo Network is a social network of amateur and professional astronomers in Japan who observe meteors and upper-atmospheric lightning. Brief history: The network was started in 2003 by T. Kanamori after he developed the meteor detection and analysis software UFOCapture. The network includes 20e30 observing stations. The SonotaCo Network website plays the role of data hub of simultaneously observed events suitable for triangulation, enables discussions, and is a portal for research. After 4 years of experimental observations, coordinated continuous observations began in 2007. Since that time, the network has recorded 22,000e42,000 meteor orbits every year (Fig. 3.7). The orbits [1] are published on the project website [2] and by the International Astronomical UniondMeteor Data FIG 3.7 Yearly count of measured orbits. Center [3]. A meteor shower catalog was published in 2009 [4], named “J4,” which contains 34 showers reduced from the first 2 years of observations (2007e2008). A more recent catalog from 14 years of observations (2007e2020), named “J14,” reports on 136 meteor showers [5]. The network has also recorded videos of a variety of transient luminous events such as sprites, elves, blue-jets, and other types of transient luminous phenomena. Technical details: The meteor detection and recording is done by a time-shift-motiondetect-video-recording-software on Windows PC, named UFOCapture, using Microsoft DirectShow interface compatible video devices. The lossy compression of brightness in mpeg or H264 is prohibited in the network. Table 3.3 shows the typical camera systems used and their angular and time resolutions. Early applications used NTSC (640  480 pixel resolution and 30 frames per second) low light video cameras, while C4K60p (4096  2160 pixel/60 fps) type observations started in 2020. In 2021, high definition (1920  1080 pixel/30 fps) board cameras that use IMX327 or IMX385 CMOS sensors with M12 or M16 mount lenses were also included. Most detected meteors are þ1 to 1 magnitude bright, with significant numbers spanning the þ4 to 5 magnitude range. All events are stored as short time-uncompressed video files that contain a video stream from a few seconds before the start of the event until a few seconds after the event’s end. UFOCapture does not recognize meteors directly, but ignores known types of interference following the flow chart of Table 3.4, and records all other luminous changes as interesting events. Captured video clips are usually checked by the human eye to reject additional events to be ignored and to recognize unusual events, using the program UFOAnalyzer, which also determines the meteor position relative to the fixed star background based on positions from a star catalog. The average measurement accuracy for each clip is computed. The measured

30

Meteoroid orbit surveys

TABLE 3.3 Typical camera systems. Type

Camera

Lens variation

SD (mono)

Watec 902H2 Ultimate Imaging source DMK33GX290e Panasonic DMC-GH3 IMX327 board IMX385 board Sony ILCE7S

2.6 mm/F1.0e12 mm/F0.8 2.6 mm/F1.0e6.0 mm/F1.4 25 mm/F0.95

HD (mono) HD (color) HD (color) 4K (color) C4K (color)

Panasonic DC-BGH1

4 mm/F0.95 6 mm/F1.0 20 mm/F2.8 85 mm/F2.8 16 mm/F1.4e25 mm/F0.95

Video format Interface

Frame rate Shutter time

Typical accuracy*

Required CPU

NTSC Analog Y800 GigE UYUV HDMI UYUV AHD/HD-SDI UYUV HDMI UYUV HDMI2.0

59.94i 17 ms 30.0p-54.0p 33e19 ms 59.94i-54.94p 33e17 ms 30.0p 33 ms 29.97p 33 ms 59.94p 17 ms

0.02 degree (8 mm lens) 1.1 degree (6 mm lens) 0.007 degree (25 mm lens) 1.1 degree (6 mm lens) 0.005 degree (20 mm lens) 0.004 degree (16 mm lens)

1 thread 2.0 GHz 4 threads 3.6 GHz 4 threads 3.6 GHz 4 threads 3.6 GHz 8 threads 3.6 GHz 16threads 3.6 GHz

Note: *, Typical accuracy assumes 0.3 pixel.

TABLE 3.4 Automated false detect exclusion flow. Cause Scintillation of star Air plane/helicopter Cosmic ray/electronic noise Bird/insect Ground object

Mask name

Masking method

Scintillation Dim star detection by time-domain averaging and contrast enhancement Slow object Object velocity measurement, cancelation of the trigger, and tacking with rectangle mask pattern Duration Duration lower limit Dark object Comparison brightness of object to background Area Masks pattern that can be set to any shape

single station meteor trajectory information is packed in an encrypted Mcsv text file, and sent to the network hub. The triangulation and the meteor orbit determination are done by software named UFOOrbit. That software is publicly available, so that everyone can download the single station observation results from the network hub and compute the trajectory, radiant, and heliocentric orbit of the meteors. However, one set of solutions is posted at the project website each year. UFOOrbit propagates the observational errors from the video clip to the final radiant and orbit parameters by using a Monte Carlo method [6]. As a result, data can be selected setting lower limits to the uncertainty. Fig. 3.8, for example, shows the radiants with better than 1
in accuracy. In addition, the uncertainty of a given radiant and orbit solution can be checked from the results of combining different sets of station tracks. Due to the overlap of camera fields, the number of simultaneous observations of one meteor is large. Over 10 simultaneous observations of a single meteor are not rare, and in 2020 on average 3.9 cameras detect a meteor from which an orbit could be calculated. For the meteors that were observed by more than two cameras, UFOOrbit applies a least square method to determine the radiant direction and speed. It selects those sets of observations that give the best accuracy [7]. When that selection is reliable, the radiant distribution of shower meteors is sharper.

31

FIG 3.8

Radiant plot of 160,531 orbits obtained by SonotaCo Network in 2007e2021.

The total number of orbits obtained in 2007e2021 was 394,408. Their average error of the radiant position (sDec.) was 3.14
, while the error in geocentric velocity (sVg) was 4.04%. When restricting sDec. < 1.0
and sVg < 5%, the number of orbits becomes 160,531, and the average sDec. ¼ 0.47
, while sVg ¼ 1.33%. Since being developed for the network in Japan, the UFOCapture and UFOOrbit software have also been used elsewhere in the world, in particular in the EMDOND and CMN lowlight video networks, results from which are presented in this book. Acknowledgments: More than 100 participants contributed to the success of the SonotaCo Network by building and maintaining the camera systems at their own expense for more than 15 years. Their voluntary contributions and inquisitive minds are worthy of respect. We thank the International Meteor Organization and individual IAU-MDC members for encouragement. In particular, we thank Sirko Molau for his pioneering efforts in video meteor observations, T. Jopek of the MDC, J. Kac the editor of WGN, as well as astronomers P. Jenniskens and S. Abe for advice, and thank M. Yamamoto who organized the TLE observation network. References: [1] Kanamori T., Masuzawa T., Sekiguchi T., Miyoshi T., Fujiwara Y., Maeda K., and Uehara S. (2021) JIMO 49, 64e70; [2] Project website: https://sonoatco.jp/; [3] MDC data website: https://www.astro.sk/iaumdcDB/home/PDA/SNMv3 (last accessed 2022 Aug. 23); [4] Kanamori T. (2009) JIMO 37, 55e62; [5] Kanamori T., Uehara S., Sekiguchi T., Fujiwara Y., Maeda K., Ueda M. (2021) JIMO 49, 76e97; [6] Kanamori T. (2016) JIMO 44, 42e45; [7] Kanamori T. (2017) JIMO 45, 95e97.

32

Meteoroid orbit surveys

GMN: The Global Meteor Network  Contributed by: D. Vida, D. Segon, D. Zubovic, and the GMN team What is the GMN? The Global Meteor Network (GMN) is a world-wide collaboration between professional and amateur astronomers with the aim of achieving global surveillance of meteors from all natural objects larger than 1 mm entering the Earth’s atmosphere [1]. The key innovation of the project is the use of low-cost digital CCTV cameras in combination with Raspberry Pi single-board computers that run open-source software. This enables the network to keep the cost of individual systems accessible to amateur astronomers. The GMN has two main operational and scientific goals. First, to provide real-time situational awareness of meteor shower activity, especially of meteor shower outbursts. This is achieved by rapidly publishing the observed meteor orbits and flux. This strategy helps inform decisions by spacecraft operators to perform maneuvers which can protect sensitive instruments from meteoroid impacts. The second goal is to observe meteorite producing fireballs to help recover the meteorites on the ground. The fireball observations yield an orbit, which can be used to determine the origin of the meteorite in the Solar System. As of 2021, the network consists of 300 camera systems in over 30 countries. The network adopted an open data conceptdorbits of all meteors are publicly available within 24 h of observation at https://globalmeteornetwork.org/. Brief history: In 2015, Sony announced the cessation of production of all CCD sensors, and a switch to CMOS technology. At the time, there were no alternatives to the analog CCD cameras in use by the amateur community. The Croatian Meteor Network, the originator of the GMN, decided to develop a new system that can work regardless of the camera technology. The key innovation was replacing expensive PCs with a Raspberry Pi (RPi) single-board computer. These computers run a free Linux operating system. Even with the SD card for storage, a power supply, and a case, the total cost of the computer is less than a regular PC. After several years of testing and developFIG 3.9 The monthly number of measured orbits. ment, the Global Meteor Network was established in late 2018, with the first few cameras installed in Canada, Croatia, and New Mexico (US). The network experienced rapid growth since, as shown in Fig. 3.9. The number of operational cameras was 73 at the end of 2019, 142 by the end of 2020, and 341 as of December 31, 2021. A total of w300,000 meteor orbits were collected until mid-2021. A plot with all radiants is shown in Fig. 3.10. Technical details: A typical GMN camera system uses either a Sony IMX291 or IMX307 IP camera. The cameras are operated at frame rates of 25 frames per second. For dark skies, a 3.6 mm f/0.95 lens is used which provides a field of view of 88
 48
and a stellar limiting magnitude of þ6.0  0.5 magnitude (depending on the sky conditions). These most common configurations have an average astrometric accuracy of w1 arc minute [2]. Narrower lenses (6 and 8 mm) are used in city conditions which mitigate the influence of light pollution. A small subnetwork of w20 cameras with narrow 16 mm lenses with a field of view of 20
 10
and

33

FIG 3.10 All meteor radiants observed by the GMN from December 2018 to June 2021. Sun-centered ecliptic coordinates are used, where the Earth’s apex (direction of motion around the Sun) is in the center. Meteor showers can be seen as bright areas of high radiant density. Reproduced from Ref. [2].

a stellar limiting magnitude of þ7.5  0.5 magnitude exists in western Croatia with the goal of computing very accurate meteor orbits (astrometric accuracy of w10 arc seconds). The GMN developed open-source software that can run on the RPi, as well as all other operating systems, and preforms end-to-end meteor data processing. The software schedules observations, collects data, detects meteors, performs data calibration, and finally reports the observations to the central server. The server-side processing pipeline then automatically correlates observations and computes meteor trajectories and orbits. A strict set of checks and filters is applied to observations [2], leaving only high-quality orbits in the final data set. The uncertainties in all parameters are computed using a Monte Carlo method by adding Gaussian noise on the order of estimated trajectory errors to original observations and refitting the trajectory solution [3]. The process described above is performed only for fainter meteors. A dedicated detector for fireballs is also run in real time, however all fireball observations are analyzed manually. Due to the high resolution of observations, the fireball wake and multiple fragments are often observed, confusing automated algorithms. For this purpose and for the purpose of creating initial astrometric plates, the SkyFit software program was developed [2]. This program implements a novel astrometric method which uses a radial polynomial with odd terms to model the distortion, while also taking atmospheric refraction and lens anisotropy (misalignment with the sensor) into account. This method uses significantly less coefficients than previous cubic polynomial methods and provides a factor of two more accurate fits on the consumer-grade CCTV lenses the GMN uses. The software was designed to make the cameras compatible with the earlier generation CAMS camera systems, so they can be deployed in an existing CAMS video camera network. The software development was supported by CAMS developer P. Gural and tested against CAMS results. GMN cameras were first used in the CAMS BeNeLux network in 2018 and since 2020 GMN cameras also helped expand the LO-CAMS network.

34

Meteoroid orbit surveys

FIG 3.11 Radiant and velocity uncertainties of GMN data (density color coded). The GMN median value is given in dashed lines, and the median CAMS value is given by a dotted line. Reproduced from Ref. [2].

Due to the density of cameras in most areas with coverage, about 40% of all meteors are observed from three or more stations. Fig. 3.11 compares the GMN and CAMS stated radiant and velocity uncertainties of sporadic meteors with total radiant uncertainties of 3. Finally, initial meteor shower studies with SAAMER-OS lacked a meteoroid deceleration correction making the comparison of meteor shower orbital elements with other surveys inaccurate [12]. Therefore a meteoroid deceleration correction for SAAMER-OS was developed in an attempt to better estimate the true out-of-atmosphere speed distribution and perform a more adequate comparison between survey results [2].

37 Acknowledgments: D. J. is with NASA-GSFC, U.S.A., J. S. B. with the Universidad de la Republica, Uruguay, R. W. with the University of Western Ontario, Canada, and J.L.H. and L.J.M. are with the Estacion Astronomica Rio Grande, Argentina, while CB is with the Universidad de La Plata, Argentina. References: [1] Hocking W. K. (1997) Radio Science 23, 687e706; [2] Bruzzone J. S., Janches D., Jenniskens P., Weryk R., Hormaechea J. (2020) PSS 188, id. 104936; [3] Janches D., et al. (2015) ApJ 809, 36e52; [4] Fritts D. C., et al. (2010) JGR: Atmospheres 115, D18, CiteID D18112; [5] Jones J., Webster A. R., Hocking W. K. (1998) Radio Science 33, 55e65; [6] Janches D., et al. (2014) JGR: Space Physics 119, 2269e2287; [7] Panka P. A., et al. (2021) The Planetary Science Journal 2, id. 197, 14 pp; [8] Weryk R. J., Brown P. G. (2012) PSS 62, 132e152; [9] Verniani F. (1973) JGR 78, 8429e8462; [10] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [11] Brown P., et al. (2010) Icarus 207, 66e81; [12] Pokorny P., et al. (2017) Icarus 290, 162e182.

JRO-Meteor: The Jicamarca radar as meteor head echo observatory Contributed by: J. L. Chau, R. F. Woodman, F. Galindo, M. Oppenheim What is JRO-Meteor? The Jicamarca Radio Observatory (JRO) is a High-Power LargeAperture Radar (HPLAR), located near Lima, Peru. Its 18,432 antennas (distributed over 300  300 m) can both transmit 50 MHz radio waves and receive the reflected signal from meteors (Fig. 3.13). JRO has been used for meteor head echo detections since early 2000 in what is called the JRO-Meteor mode. In this mode, JRO-Meteor utilizes the large array for FIG 3.13 The Jicamarca HPLAR. transmission and at least three quarters of the antenna for reception. The interesting reflections are those from the head of the meteor. From the direction of the reflection and the time it takes to receive the transmitted signal, the radial velocity and acceleration, as well as the trajectory of the meteor are measured. So far, JRO-Meteor has been only operated on short campaigns of a few hours each at different seasons and years. Details of the JRO-Meteor mode can be found in Ref. [1], while the sporadic population and meteor showers detected with JROMeteor can be found in Refs. [2] and [3], respectively. Brief history: Motivated by the expected intense Leonids meteor shower in 1998, scientists involved with HPLARs around the world ran dedicated campaigns to observe this shower using different radio frequencies at different facilities. Dr. Ronald Woodman, JRO Director at the time, proposed an observing campaign with Jicamarca’s HPLAR. To the surprise of many HPLAR experts, early observations showed unexpected large numbers of meteorhead echoes. At the time, it was assumed that pointing at the Leonid radiant meant that these were Leonids. All HPLAR meteor detections were assumed to be meteors coming down the narrow beam. However, large rates were also observed during controlled days before and after the Leonids shower. A few years later, radar interferometry was applied at Jicamarca [1], whereby the meteor path could now be measured using different parts of the array. From the new observations, the originally enigmatic results were understood, namely,

38

Meteoroid orbit surveys

most HPLAR meteor detections during the 1998 Leonids were due to the strong sporadic apex source meteoroid population that moved through the beam at different angles and speeds. Based on the unique ability of radar interferometry to measure the direction of motion of the meteors, a series of campaigns were conducted between 2001 and 2009. Initially, an automatic detection and identification procedure was used to differentiate meteor-head echoes from the clutter due to ionospheric plasma reflections [1]. Campaigns after 2005 were processed manually, allowing higher quality detections [2]. A catalog based on the majority of verified JRO-Meteor detections was published by Ref. [2], and the first definite detection of meteor showers with HPLARs was published by Ref. [3]. The JRO-Meteor data set was part of F. Galindo’s engineering thesis [4], E. Fucetola’s Ph.D. thesis [5], and incorporated into a global micrometeoroid influx model [6]. Ref. [5] focused on the dynamical masses of the detected meteors and found that the majority of masses range from around 104 to 1012 g with a peak at approximately 108 g. Technical details: The JRO-Meteor mode consists of: (a) transmission with the full 300  300 m Jicamarca antenna between 1 and 2 MW peak power, and (b) reception with at least three of the four Jicamarca quarters (150  150 m each). The transmitted signal is broadcast over a narrow 1e3 degree beam that crosses the meteor layer in the atmosphere. JRO-Meteor samples an area that is only a very small portion of the sky over Jicamarca; however, a few tens of thousands of meteors per day are detected routinely. On occasions up to 2e4 meteors have been detected in a second. The transmitted signal is in the form of narrow radio pulses. They are phase coded using a Barker code with length 13 to improve range resolution for relatively long transmission pulses. Some campaigns have used uncoded narrow pulses of 1 ms width. The latter mode is less sensitive, but allows a better determination of radial velocity and therefore absolute velocity as well as result in less clutter from plasma irregularities. The resolution in Range is between 150 and 450 m, depending on the goals of the campaign. The trajectory is measured using radar interferometry with the three receiving quarters. The velocity and interferometry precision depend on signal-to-noise ratio (SNR) and elevation angle of the meteor trajectory. The JRO-Meteor database includes the elevation angle and SNR for each meteor detection; however, the precision of interferometric angles is not provided. Nonetheless, using Monte Carlo simulations, the expected uncertainties of these parameters were calculated. Fig. 3.14 shows an example of what are the percentage errors of absolute velocity for a given elevation angle and SNR. There is less precision for meteor speeds with radiant elevation angles less than 30 degrees than those with higher radiant elevation angles. Meteors with a higher radiant elevation angle move more down the beam, providing a longer FIG 3.14 Velocity precision as function of meteor period of detection. The uncertainty in the elevation angle and SNR: 20 dB (green), 10 (red), blue radiant position (Fig. 3.15) is also mostly a func(5 dB). After Ref. [4]. tion of elevation angle and SNR. Compared to the error in elevation, the error in azimuth is relatively small, given the good localization of the meteor-head echoes.

39

FIG 3.15 Elevation precision as function of meteor elevation angle and SNR: 20 dB (green), 10 (red), blue (5 dB). After Ref. [4].

Given Jicamarca’s relative low transmission frequency, echoes from other plasma irregularities (nonspecular meteor or equatorial electrojet irregularities) normally coexist with the meteorhead echoes. Fig. 3.16 shows an example of the coexistence of meteor-head echoes (tilted narrow lines) and ionospheric echoes. In most HPLARs (such as Arecibo, EISCAT, and MU Radar), meteor-head echo detection is mainly done with a high-pass filter [7], since meteor velocities are much greater than those of other atmospheric and ionospheric targets. Because of the low transmission frequency of Jicamarca, echoes from plasma irregularities can be more than 3e5 orders of magnitude stronger than those from meteors. That makes high-pass filters ineffective. Therefore, conservative automatic meteor detections have been implemented at times when ionospheric FIG 3.16 Altitude-time diagram of received reflections, showing both meteor-head echoes and echoes from plasma irregularities. After Ref. [4].

echoes are weak, while more aggressive manual detections have been applied when the ionospheric echoes are strong. The example of Fig. 3.16 was taken with an uncoded pulse and only shows the SNR. When coded pulses are used, the separation of echoes is even harder. Since head echoes have different Doppler shift characteristics than electrojet irregularities, Doppler data can improve head echo detection. Acknowledgments: The Jicamarca Radio Observatory is a facility of the Instituto Geofísico del Perú operated with the support from NSF award AGS-1732209 through Cornell University. References: [1] Chau, J. L., Woodman, R.F. (2004) ACP 4, 511e521; [2] Chau, J. L., Woodman, R. F., Galindo, F. (2007) Icarus 188, 162e174; [3] Chau, J. L., Galindo, F. (2008) Icarus 194, 23e29; [4] Galindo, F. (2006) Engineering Thesis, Universidad Nacional de Ingeniería, Peru; [5] Fucetola, E. (2012) Determining Meteoroid Properties using Head Echo Observations from the Jicamarca Radio Observatory. Ph.D. thesis, Boston University, 139 pp; [6] Janches D., Heinselman C., Chau J. L., Chandral A., Woodman R. F. (2006) JGR 111, A07317; [7] Kero J., Campbell-Brown M., Stober G., Chau J. L., Mathews J., Pellinen-Wannberg A. (2019) In: Meteoroids, Sources of Meteors on Earth and Beyond, Eds.: Ryabova G. O., Asher D. J., CampbellBrown M. D., Cambridge: Cambridge University Press, p. 65e89.

40

Meteoroid orbit surveys

MAARSY: The Middle Atmosphere Alomar Radar System Contributed by: C. Schult and G. Stober What is MAARSY? The new Middle Atmosphere Alomar Radar System (MAARSY) is a VHF monostatic High-Power LargeAperture (HPLA) radar system installed at Andenes on the Northern Norwegian island Andøya (69.30
N, 16.04
E) [1]. See Fig. 3.17. The radar was designed for observations of tropospheric winds and Polar Mesosphere Summer Echoes [2,3,5,9], but can also be used for the observation of meteor-head echoes [4,7] or transverse scatter meteor echoes [11]. Brief history: In 2009 the antenna array FIG 3.17 MAARSY antenna array and six control installation was completed. This initial setup containers. Photo taken by Ralph Latteck. used a linear polarized antenna. In 2010 the radar started its operation with a partial array before in 2011 all transceiver modules were integrated [2]. In 2012, the antenna array was upgraded to circular polarization by adding a second dipole, reflector, and director plane with a 90
phase offset to each antenna pole. Since 2012 the main hardware of the radar remained unchanged and was continuously in operation. Technical details: MAARSY is a monostatic radar system operated at 53.5 MHz with an active phased array antenna consisting of 433 Yagi antennas. The 3-element Yagi antennas are arranged in an equilateral triangle grid. The antenna array is divided into 61 subgroups, 55 of the groups are hexagons and consist of 7 antennas each, 6 subgroups contain 8 antennas each and are located at the perimeter of the antenna array, which makes the overall field approximate a circular area of 6300 m2. The beamwidth of the radiation pattern of a single hexagon structure is about 30
, and that of a combination of 7 adjacent hexagonal subgroups (anemone structure) is about 11
. Each individual antenna is connected to its own transceiver with independent phase control, a scalable output of up to 2 kW, and tunable to a certain frequency within the assigned bandwidth. A symmetric radar beam can be formed with a minimum half-power beamwidth of 3.6
, a maximum directive gain of 33.5 dBi, and a total transmitted peak power of approximately 866 kW. The IF signals of each 7 transceivers connected to every 7 antennas arranged in a hexagon are combined to 61 receiving channels. Selected channels or combinations of IF signals are sent to a 16-channel data acquisition system with 50 m sampling resolution and 16-bit digitization specified. The high flexibility of MAARSY allows classical Doppler beam swinging as well as experiments with various beam widths and the use of modern interferometric applications. Meteor-head echo observations: After the first meteor-head echo campaign in 2012 [4], a new data processing pipeline was implemented in the MAARSY receiver branch. The main goal of this new data processing was to leverage all observations for the meteor head echo detection rather than to run dedicated meteor campaigns, which are very expensive considering the operational costs for an HPLA radar such as MAARSY. Atmospheric observations often use pulse coding to optimize the sensitivity, which was automatically decoded before the data stream was stored. However, meteor-head echoes travel at such a high speed that the decoding is required to account for their Doppler velocity [7]. Therefore, the raw data stream

41 was separated before the data storing in an atmospheric data stream and the meteor-head echo pipeline and, thus, enabled a continuous meteor-head echo monitoring program to study the sporadic meteor sources [7] as well as meteor streams with an HLPA radar [8]. The analysis procedure computes the meteoroid range, velocity, and deceleration as functions of time. The accuracy of meteor radiants is about 1e2 degrees on average, while the speed is measured to about 0.2e5 km/s [4,7,10]. Another advantage of the head echo observations is the precise localization of the meteor inside the beam volume, which permits deriving absolute radar cross-sections and constraining the meteoroid mass [7,12]. The meteoroid mass calculated from dynamical modeling [7] suggests that typical meteoroid masses are about 0.0001 g at entry (corresponding to visual magnitude Mv w þ9.3 for speed Vg ¼ 20 km/s, Mv w þ7.3 for Vg ¼ 40 km/s and Mv w þ6.1 for Vg ¼ 60 km/s). A mean meteoroid density of 0.6e0.8 g/cm3 was found from most meteoroids that followed cometary-type orbits (apex source) prior to Earth impact. Furthermore, this continuous mode is also ideal to perform joined radar-optical surveys, which are otherwise more challenging due to the weather conditions. From 2015 to 2017 two meteor camera systems, each containing a wide-field all-sky and a narrow field highresolution camera, were installed around MAARSY pointing toward the vertical beam position at 100 km [6]. In total 105 high-resolution joined meteor head echo-optical detections were made. The median radiant position agreed to within 1.5
between the radar and the cameras and about 30% of the events had an even better agreement than 1
. MAARSY detections indicated a 0.5 km/s higher velocity compared to the optical systems. In addition, there was a tendency that the radar detected the meteors earlier along the flight path by about 1.3 km on average, which is attributed to the higher sensitivity of the radar in relation to the optical system [6]. The optical observations were complemented by a joined MAARSY-EISCAT-optical campaign. The EISCAT UHF radar was pointed toward the MAARSY beam volume at about 104 km above Andenes [12]. The mean difference between both radars was about 17 dBsm consistent with the Rayleigh regime. Assuming a Gaussian overdense plasma distribution, the meteoroid masses were estimated to be about 100 mg for particles with mean densities of about 0.6e0.8 g/cm3. Finally, the MAARSY beam was pointed to 30
off-zenith toward East leveraging the highpower aperture to observe the faintest possible ionization of meteors in transverse scatter geometry. This experiment was designed to search for the micro-meteoroid limit that could be detected and reached a limiting radar magnitude of þ16. The velocity peak of the sporadic meteors was observed at about VN ¼ 19 km/s and, after applying the observational filter corrections, the velocity peak of the meteoroid influx was at 13 km/s. According to meteor ablation modeling, the detected meteors were close to the micrometeor ablation limit [11]. Acknowledgments: CS worked previously at the Leibniz-Institute of Atmospheric Physics, University of Rostock, Germany. GS is affiliated with the University Bern, Switzerland, and the Oeschger Center for Climate Change Research. The meteor head echo observations with MAARSY were funded by grant STO 1053/1-1 (AHEAD) of the Deutsche Forschungsgemeinschaft (DFG). The optical observations by MCB and PB were supported by the NASA Meteoroid Environment Office through cooperative agreement 80NSSC18M0046 and by the NASA Solar System Workings grant NNH14ZDA001N-SSW. The transmission and reception technology of the radar was manufactured by the Australian company Genesis Software Pty Ltd. References: [1] Latteck R., Singer W., Rapp M., Vandepeer B., Renkwitz T., Zecha M., Stober G. (2012) Radio Science 47, 18 pp; [2] Stober G., Latteck R., Rapp M., Singer W., Zecha M., (2012) Adv. Radio Sci. 10, 291e298; [3] Stober G., Sommer S., Rapp M., Latteck R. (2013)

42

Meteoroid orbit surveys

Atmos. Meas. Tech. 6, 2893e2905; [4] Stober G., Schult C., Baumann C., Latteck R., Rapp M. (2013) Ann. Geophys. 31, 473e487; [5] Sommer S., Chau J. L., Schult C. (2016) JGR 121, 6713e6722; [6] Brown P., Stober G., Schult C., Krzeminski Z., Cooke W., Chau J. L. (2017) PSS 141, 25e34; [7] Schult C., Stober G., Janches D., Chau J. L. (2017) Icarus 297, 1e13; [8] Schult C., Brown P., Pokorny P., Stober G., Chau J. L. (2018) Icarus 309, 177e186; [9] Stober G., Sommer S., Schult C., Latteck R., Chau J. L. (2018) Atmos. Chem. Phys. 18, 6721e6732; [10] Mazur M., Pokorny P., Brown P., Weryk R. J., Vida D., Schult C., Stober G., Agrawal A. (2020) Radio Sci. 55, doi:10.1029/2019RS006987; [11] Schult C., Stober G., Brown P., Pokorny P., Campbell-Brown M. (2020) Icarus 340, 1e12; [12] Schult C., Kero J., Stober G., Brown P. (2021) Icarus 355, 1e10.

MU radar: The MU radar as a meteor head echo observatory Contributed by: J. Kero, C. Szasz, T. Nakamura, D. Kastinen, and the radar meteor head echo database group What is the MU Radar? The Shigaraki 46.5 MHz MU radar (Middle and Upper atmosphere radar) is a High-Power LargeAperture (HPLA) type radar located at þ34.85
N and 136.10
E in Japan (Fig. 3.18). During the years 2009e2010, this facility was used to systematically measure meteor-head echoes during an interval each month, in order to determine precise meteor orbits. This meteor-head echo observation program recorded in total 528.8 h of data and the trajectories of more than 106,000 meteor-head echoes with precisely deterFIG 3.18 The Shigaraki MU radar. mined orbits. The results were published in Refs. [1,2]. Some meteor showers are present in the data. Ref. [3] presented results on the 2009 Orionid meteor shower. Ref. [4] focused on the 2010 Geminids. Refs. [5,6] presented results for the 2011 and 2012 October Draconids from later observing campaigns. Brief history: The aim of the 2009/2010 MU Radar meteor head-echo program was to map the sporadic meteor population, but meteor showers were also detected. Each month, the radar was operated with an identical experimental setup. The observations covered at least one diurnal cycle during each monthly observational campaign. The duration of each campaign varied, from 21.0 h of data and almost 5000 head echoes conducted in 2009 December, to 691 h of data and more than 23,000 head echoes measured in 2010 October. No observations were made in 2009 August. The overall detection rates varied with the season, with more meteors observed around the autumnal equinox than around the vernal equinox [2]. Technical details: The MU radar consists of 475 crossed Yagi antennas in a circular space with a diameter of 103 m. The antennas are arranged in 25 subgroups of 19 Yagi antennas, with one transmitter/receiver module each. The antenna subgroups can be operated as an interferometer, in order to measure the direction and distance of meteor-head echoes. The data from each subgroup of antennas are stored as a separate digital channel. The combined transmitters have a peak power of 1 MW. The beam width of the MU radar system is 3.6
at full width at half-maximum, which is wider than for most other HPLA radar

43 systems. A larger volume of the atmosphere is probed and meteors are detected over a larger part of their trajectory. During the observations described here, the radar beam was pointed toward the zenith and head echoes were detected over the height range from 73 to 127 km, with data transfer rates limited by the maximum data rate of 20 Gb/h [1]. When operated in the general head echo mode, the range to meteors was determined with a precision of the order of 10 m using range finding interpolation [1]. The radar pulses were transmitted with 13-bit Barker-code, for a total pulse length of 156 ms and interpulse period of 3.12 ms to use the 5% duty cycle. The received data were stored as 85 range values from each transmitted pulse, sampled at 6 ms intervals [1]. The radar was stopped and restarted every full hour. This was to reboot the system and avoid memory buffer overflow, which could happen when the data rate was close to the system limit. Because of this, there is no data for the first 1e2 min of every full hour. This is taken into account when calculating influx rates. The analysis procedure computes the meteoroid range, velocity and deceleration as functions of time. Typical measurement uncertainties of individual meteor radiants seem to be around 1
, even if the radiant is far from the zenith [5]. The line-of-sight velocity (vertical component, as the radar beam was oriented toward the zenith) is typically measured better than about 1 km/s [1]. The accuracy of the meteoroid velocity determination procedure depends on how large a fraction of the vertical component is represented as well as how accurately the radiant was estimated. Meteoroid masses have been investigated by combining MU radar observations with simultaneous optical observations using an array of CMOS sensors mounted on the 1.05-m Kiso Schmidt telescope [7]. The campaign resulted in 331 simultaneously observed meteors over the absolute visual magnitude range þ3 to þ11 (peaking at þ8.3). A linear function was derived that relates the peak radar cross-section (A) to the meteor’s peak absolute Vband (visible) magnitude: MV ¼ (4.43  0.13) þ (0.169  0.006)  A, where A is the RCS in units of dBsm [7]. From this, a sporadic mass distribution index of c ¼ 3.52  0.12 was found, biased toward meteors in the þ4 to þ8 magnitude range. This study found that the MU radar is capable of detecting meteoroids down to w105 g, but is complete only to about 5  104 g. A previous study, comparing the flux of MU radar Orionids to the flux of Orionids observed using other methods, resulted in a slightly lower mass limit [3]. Acknowledgments: The MU Radar facility is owned and operated by the Research Institute for Sustainable Humanosphere (RISH) at Kyoto University, Japan. The meteor head-echo data (MURMHED) used in this book have been created by T. Nakamura (National Institute of Polar Research, Japan), J. Kero (Swedish Institute of Space Physics, Sweden), and members of the radar meteor head echo database group under the support by the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Publication of Scientific Research Results (KAKENHI Databases) Grant 258033. References: [1] Kero J., Szasz C., Nakamura T., et al. (2012) Ann. Geophys. 30, 639e659; [2] Kero J., Szasz C., Nakamura T., et al. (2012) MNRAS 425, 135e146; [3] Kero J., Szasz C., Nakamura T., et al. (2011) MNRAS 416, 2550e2559; [4] Kero J., Szasz C., Nakamura T. (2013) Ann. Geophys. 31, 439e449; [5] Kero J., Fujiwara Y., Abo M., Szasz C., Nakamura T. (2012) MNRAS 424, 1799e1806; [6] Fujiwara Y., Kero J., Abo M., Szasz C., Nakamura T. (2016) MNRAS 455, 3273e3280; [7] Ohsawa R., et al. (2020) PSS 194, id.105011.

44

Meteoroid orbit surveys

AMOR: The advanced meteor orbit radar Contributed by: W. J. Baggaley What is AMOR? AMOR is a multistation high frequency radar system that was established on New Zealand’s South island, 40 km South-East of Christchurch, in 1990 and operated until 2003. The transmitter near the central receiver site radiated a fanlike beam toward geographical south and north, providing direct backscatter to the central station and specular reflections to two outstations. The radar does not provide all-sky maps of radiants, but rather isolated directions of meteor motion FIG 3.19 The advanced meteor orbit radar. (radiant) in a narrow range of azimuth due to the fanlike geometry. In the early years, most radiants were detected in the declination range þ5 to 30
. Deep southern radiants were surveyed more efficiently after an upgrade in 1993 [1,2]. Technical details: The system used a 26.2 MHz, 50 kW pulse radar transmitter, and a narrow colinear array (Fig. 3.19), creating a fan-shaped antenna beam (width 3.2
to 3 dB) to confine the echo azimuth of detected meteor trails. That way, only the elevation angle needed to be measured. This was done by phase comparison using three antennas of separations 3l and 10l. The velocity and radiant position were obtained from measuring the time-lags between detection at multiple receiver sites over an 8-km baseline. Independent velocity determinations were obtained through the phase behavior and Fresnel diffraction profile as the train forms. From this, atmospheric decelerations were obtained in 5%e10% of cases. An upgrade to the antenna system using 40l length colinear arrays was implemented in May 1993, resulting in beam-widths a factor 2.5 narrower and coverage of north as well as south directions in elevation. AMOR’s limiting sensitivity, after the 1993 upgrade, is about equal to a visual meteor magnitude of þ13.5, which for a typical speed of 35 km/s corresponds roughly to a mass of w5  107 g or a meteoroid diameter of w100 mm [2]. The directional accuracy for meteor radiants is about 2
, the speed from Fresnel diffractions is measured to a precision of about 0.7 km/s, but a speed-dependent deceleration correction is applied to obtain preatmospheric velocities, introducing some additional uncertainty. Representative uncertainties in orbital elements are about 2
in i and u and 5% in semi-major axis and eccentricity [2]. Acknowledgments: The AMOR Radar was operated by the University of Canterbury, Christchurch, NZ. References: [1] Baggaley W. J. (2001) ASR 28, 1277e1282; [2] Baggaley W. J., Bennett R. G. T., Steel D. I., Taylor A. D. (1994) QJRAS 35, 293e320.

C H A P T E R

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The Atlas: Overview and major showers

Atlas of Earth's Meteor Showers https://doi.org/10.1016/B978-0-323-88447-1.00015-6

45

© 2024 Elsevier Inc. All rights reserved.

46

The Atlas: Overview and major showers

47

March

March 21 (lo ¼ 0 )

130 DME d delta Mensids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.85  0.25 Annual shower March 3eApril 6 (lo ¼ 342 e16 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 359.7 71.2 79.4 283.8 75.9 37.0 1.20 þ0.13 0.13 0.07 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 26.7 0.963 0.963 59.6 353.0 179.7 172.5 0.0034 0.107 2.51 2.96 5.88 2.96 þ0.0004 þ0.0034 0.01 þ0.09 þ1.00 þ1.09 N ¼ 124 (hr ¼ 33.5 , m(Mv ¼ 0) ¼ 0.09 g) w0.2/h c ¼ 2.70  0.06 (s ¼ 2.08  0.02) I: Hb ¼ 107.4  1.69 Mv; Hmax ¼ 95.2 þ 1.46 Mv; He ¼ 89.9 þ 2.25 Mv (N ¼ 110) IIa: Hb ¼ 100.7  2.59 Mv; Hmax ¼ 92.2 þ 0.18 Mv; He ¼ 86.3 þ 0.68 Mv (N ¼ 13) F ¼ 0.664  0.0470 Mv I: r w 0.99 g/cm3 (a1 ¼ 0.078 km, a2 ¼ 5.24/s) IIa: possibly Na poor/free

Lightcurve shape: Meteoroid density: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

March 3e31 (lo ¼ 349 e10 ) lo ( ) R.A. ( ) Decl. ( ) 356.8 75.3 77.2 0.16 þ0.32 a (AU) q (AU) e 2.18 0.987 0.556 0.0107 0.184 þ0.0004 þ0.0031 N ¼ 740

b ( ) 77.3 0.07 u ( ) 348.2 8.96 þ0.19

Vg (km/s) 28.5 0.00 U ( ) 176.9 2.90 þ1.00

Age: Source: Orbital elements (J2000.0) Epoch 1804-Feb-14.1 TDB

From c and s: w37,000 y; From model: w51,000 y C/1804 E1 (Pons) a (AU) q (AU) e i ( ) u ( ) N 1.071 1.000 56.4 331.9

U ( ) 179.5

l ( ) 292.3 þ0.39 i ( ) 48.6 4.51 0.04

P ( ) 164.5 8.96 þ1.19

eV

e R[S]

duncertain P ( ) 151.5

Brief history: Annual shower, radiant close to episodic shower #108. Known by southern hemisphere visual observers as a weak shower during March 13e21 [1,2] (Fig. 4.1). First orbits from video observations by CAMS New Zealand in 2015 and 2016 [3]. This work shows strong change of longitude of perihelion with solar longitude. Source identified as C/1804 E1 (Pons) by [4], with a theoretical radiant at R.A. ¼ 34.5 , Decl. ¼ 73.2 , VN ¼ 34.9 km/s around lo ¼ 358.3 , but being linked to Adelaide radar shower 3.05. It is uncertain that this radar shower is #130. Name is that used by visual observers [1]. Number assigned by [5]. References: [1] Wood J. (1990) Jeff Wood’s List. Meteor Showers by Date of Maximum. Perth: NAPO-MS, 6 pp; [2] Kronk G. W. (2014) Meteor Showers. An Annotated Catalog. New York: Springer, p. 60; [3] Jenniskens P., Baggaley J., Crumpton I., Aldous P. (2016) JIMO 44, 187e189; [4] Gartrell G. (1972) Proc. Astron. Soc. Australia 2, 89e90; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: Cambridge Univ. Press, p. 701. FIG 4.1

Zenith hourly rate curve.

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The Atlas: Overview and major showers

April

April 6 (lo ¼ 17 )

517 ALO d April lambda Ophiuchids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.13  0.25 Annual shower March 31eApril 17 (lo ¼ 10 e28 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 16.8 245.2 þ1.4 227.0 þ22.6 56.1 þ1.07 þ0.14 þ0.12 þ0.31 0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 31.8 0.303 0.990 110.8 293.7 16.8 310.2 0.0309 0.0250 1.62 4.06 4.09 4.06 þ0.0067 þ0.0002 0.26 0.84 þ1.00 þ0.18 w0.06/h (N ¼ 137, hr ¼ 48.6 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.52  0.28 (s ¼ 2.00  0.11) IIa: Hb ¼ 106.7  0.80 Mv; Hmax ¼ 96.7 þ 1.18 Mv; He ¼ 91.1 þ 1.92 Mv (N ¼ 68) IIa: r w 1.09 g/cm3 (a1 ¼ 0.046 km, a2 ¼ 5.92/s) From c and s: 16,000 y; From model: w41,000 y e

49

eV

Brief history: First reported by [1], when 20 video-triangulated orbits were recorded by the Croatian Meteor Network and SonotaCo network from R.A. ¼ 244.6 , Decl. ¼ þ1.1 and Vg ¼ 55.7 km/s around lo ¼ 15.5 . Present in each year from 2007 to 2011. Name and number by [1]. Reference: [1] Andreic Z., et al. (2013) JIMO 41, 103e108. April 15 (lo ¼ 25 )

839 PSR d phi Serpentids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.34  0.29 Episodic shower, some annual activity 2019, 2020 April 13e17 (lo ¼ 23 e27 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 25.0 242.1 þ13.9 211.7 þ34.2 45.6 þ0.80 0.18 0.03 þ0.00 þ0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 122.0 0.429 0.996 69.0 278.1 25.0 303.3 0.0087 0.0234 1.11 1.62 0.73 1.62 þ0.0006 þ0.0036 þ0.11 0.19 þ1.00 þ0.81 w0.05/h (N ¼ 51, hr ¼ 51.2 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 1.66  0.05 (s ¼ 1.55  0.03) Component Ib has low He with Ke < 82: Ib: Hb ¼ 105.0  0.27 Mv; Hmax ¼ 94.4 þ 2.04 Mv; He ¼ 89.4 þ 2.03 Mv (N ¼ 25) Ib: r w 0.66 g/cm3 (a1 ¼ 0.020 km, a2 ¼ 5.95/s) From c and s: 11,000 y; From model: w15,000 y e

Meteoroid density: Age: Source:

eV

Brief history: Compact shower close to #27. First recognized to be two showers close together by [1]. Name and number assigned by [1] to the compact component at R.A. ¼ 242.2 , Decl. ¼ þ14.0 and Vg ¼ 46.3 km/s around lo ¼ 25.1 . Higher rates in 2019 and 2020 [2,3]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29; [2] Jenniskens P. (2020) Phi Serpentid Meteor Shower. CBET 4756. Ed.: D. W. E. Green. Cambridge: CBAT, 1 pp; [3] Roggemans P., et al. (2020) eMeteorNews 5, 178e185.

50

The Atlas: Overview and major showers

April

51

April 17 (lo ¼ 27 )

136 SLE d sigma Leonids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter family comet, TJ ¼ þ2.94  0.12 Annual shower, variable rates 1953/1954, 2020 April 1eMay 15 (lo ¼ 10 e55 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 27.1 200.7 þ4.7 170.1 þ12.3 20.1 þ0.55 þ0.11 0.52 þ0.30 0.18 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.73 0.719 0.738 7.3 250.4 27.1 278.2 eV 0.0195 0.0920 0.83 2.12 9.37 2.12 þ0.0063 0.0019 þ0.07 0.86 þ1.00 þ0.15 w0.2/h (N ¼ 516, hr ¼ 47.8 , m(Mv¼ 0) ¼ 0.37 g) c ¼ 3.09  0.06 (s ¼ 2.22  0.02) I: Hb ¼ 98.0  1.60 Mv; Hmax ¼ 84.8 þ 1.10 Mv; He ¼ 80.1 þ 1.54 Mv (N ¼ 315) IIa: Hb ¼ 92.4  1.47 Mv; Hmax ¼ 82.3 þ 0.76 Mv; He ¼ 77.6 þ 1.04 Mv (N ¼ 134) III: Hb ¼ 83.2  0.71 Mv; Hmax ¼ 79.7  0.17 Mv; He ¼ 76.2 þ 0.46 Mv (N ¼ 60) I: r w 1.47  0.30 g/cm3 (a1 ¼ 0.099 km, a2 ¼ 2.56/s) IIa: r w 2.39  0.43 g/cm3 (a1 ¼ 0.091 km, a2 ¼ 2.39/s) dNa poor dpossibly Na free III: r w 1.80  0.66 g/cm3 (a1 ¼ 0.0495 km, a2 ¼ 6.55/s) Mg0.39 Fe0.29 Na0.011 (N ¼ 1), strong O emission e #21 AVBdalpha Virginids 2020 FV6 duncertain, possible interloper a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.65 0.730 0.724 3.18 252.5 29.0 281.5

Meteoroid density:

Spectroscopy: Age: Alternative name: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

Brief history: This section pertains to the stronger lower latitude component of the a-Virginids (#21) (Fig. 4.2). We assumed here that both #136 and #21 are from the same source, but representing different episodes of activity. The #136 component aligns in radiant evolution with the higher latitude part, which is rightfully called #21, but not in the evolution of speed (see #21 in Chapter 10). As a result, the orbital elements also do not evolve smoothly. Video yearly tally of #136 starting in 2007: 2, 2, 8, 3, 23, 18, 35, 33, 43, 42, 32, 65, 63, 218, suggests periodic higher rates with P w 4.5 y. Possible source 1998 SH2 identified by [1,2], possible source 2020 FV6 identified here. This part of the shower has been called the s-Leonids by [3], giving R.A. ¼ 202.9 , Decl. ¼ þ4.7 and Vg ¼ 16.6e22.9 km/s centered on lo ¼ 28 . The name dates back to [4], finding 27 meteors with a common radiant at R.A. ¼ 171.4 , Decl. ¼ þ6.4 and Vg ¼ 21.5 km/s centered on lo ¼ 359 (between February 6 and May 23). [5] linked the shower to asteroidal material, including Pribram. Number by [2]. References: [1] Wiegert P. (2004) Presentation at: Meteoroids 2004. London: University of Western Ontario; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: C.U.P., p. 704; [3] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [4] Southworth R. B., Hawkins G. A. (1963) SCoA 7, 261e285; [5] Kresak L. (1963) BAC 14, 49e52.

FIG 4.2

Radiant evolution of a-Virginids (#136 and #21).

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The Atlas: Overview and major showers

April

53

April 22 (lo ¼ 32 )

6 LYR d April Lyrids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak time: Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.48  0.17 Annual shower 687 BCE, 15 BCE, 1803, 1922, 1945, 1982 April 16e27 (lo ¼ 26 e37 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 32.3 272.2 þ33.4 241.1 þ56.8 46.6 þ0.71 0.32 þ0.07 0.34 þ0.35 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 18.2 0.920 0.949 79.4 214.2 32.3 246.5 eV 0.0161 0.104 2.17 3.92 1.17 3.48 þ0.0014 0.0057 þ0.52 0.17 þ1.00 þ0.83 N ¼ 7960 (hr ¼ 59.8 , m(Mv¼ 0) ¼ 0.05 g) Median: lo ¼ 32.3 ; Peak activity: lo ¼ 32.18  0.05 [21] Annual: ZHR ¼ 12.8  0.7/h, B ¼ 0.22  0.01 [16]; ZHR ¼ 16  2/h [20] c ¼ 2.13  0.03 (s ¼ 1.82  0.02); c ¼ 2.7 [16]; 2.36  0.11 [18]; 2.1 [19] Ib: Hb ¼ 107.3  1.09 Mv; Hmax ¼ 97.3 þ 1.50 Mv; He ¼ 91.7 þ 2.06 Mv (N ¼ 2851) IIb: Hb ¼ 96.2  0.41 Mv; Hmax ¼ 91.0 þ 0.21 Mv; He ¼ 85.9 þ 0.74 Mv (N ¼ 112) Ib: F ¼ 0.64, IIb: F ¼ 0.50, more like III r ¼ 0.41  0.12 g/cm3 [7] Ib: r  0.74  0.11 g/cm3 (a1 ¼ 0.0605 km, a2 ¼ 5.63/s), lower if fragile dchondr. Na IIb: r w1.38  0.50 g/cm3 (a1 ¼ 0.085 km, a2 ¼ 5.37/s) dlikely Na free Mg0.82 Fe0.77 Na0.080 (N ¼ 7), Na enriched 20,000 y with b ¼ 0.008, best fit to our lo, radiant, and speed [15]; From c: w17,000 y; From model:w29,000 y; Tail (s) w 51,000 y; Earth through core of stream (sU < su) C/1861 G1 (Thatcher) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 55.7 0.921 0.983 79.8 213.4 31.9 245.1

Lightcurve shape: Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1861-May-25.0 TDB

Brief history: Shower first widely noticed during 1803 outburst over eastern U.S.A. [1]. Recognized as an annual shower in 1839 [2] (Activity in Fig. 4.3). Historic outbursts identified by [17]. Comet C/1861 G1 identified as parent by [14]. Periodic activity investigated by [4]. First photographed orbits by [5]. Physical data from photographed orbits presented in [7,8]. Detected by radar in [9], first radar orbits by [10]. First visual ZHR activity profile by [11]. First modeling of the orbit precession by [12]. Sixty-year outbursts explained from a 1-revolution cometary dust trail moving in and out of Earth’s orbit in [13]. Recent model by [15]. Shower number assigned by [6]. Named by [3]. FIG 4.3 Annual ZHR profile. References: [1] Virginia Gazette and General Advertiser of 1803 April 23; [2] Herrick E. C. (1839) AJSCA 2nd Ser. 35, 361e363; [3] Denning W. F. (1878) MNRAS 38, 396e397; [4] Guth V. (1947) BAC 1, 1e4; [5] Wright F. W. (1960) AJ 65, 33e39; [6] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [7] Jacchia L. G., Verniani F., Briggs R. E. (1965) SAO special report #175, Cambridge NY:SAO, 309 pp; [8] Verniani F. (1967) SCoA 10, 181e195; [9] Hawkins G.S., Almond M. (1952) MNRAS 112, 219e233; [10] Sekanina Z. (1972) Icarus 13, 475e493; [11] Veltman R. (1984) Radiant, Journal of the DMS 6, 81e84; [12] Fox K. (1986) In: Asteroids, Comets, Meteors II. Uppsala: Upssala Univ., p. 521e525; [13] Jenniskens P. (1997) AA 317, 953e961; [14] Weiss E. (1867) AN 24, 381e384; [15] Hajduková M., Neslusan L. (2021) PSS 203, id. 105,246; [16] Jenniskens P. (1994) AA 287, 990e1013; [17] Newton H. A. (1863) AJSCA 2nd Ser. 36, 145e149; [18] Dubietis A., Arlt R. (2003) JIMO 31, 97e98; [19] Rendtel J. (2021) IMO 2022 Meteor Shower Calendar. Potsdam:IMO, p. 25e25; [20] Molau S., et al. (2015) JIMO 43, 115e120; [21] Roggemans P., et al. (2019) eMeteorNews 4, 4e13.

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The Atlas: Overview and major showers

May

55

May 6 (lo ¼ 46 )

31 ETA d eta Aquariids

Dynamic type: Shower type: Years of outbursts:

Long-period comet shower from Halley-type comet, TJ ¼ 0.46  0.31 Annual shower, episodic outbursts 1993e1996: lo w 45.1 , ZHRoutburst ¼ 40/h [11,15] 2004: lo w 45.1 , ZHRoutburst ¼ 90/h [15,16] 2013: lo w 45.1 , ZHRoutburst ¼ 90/h [15,16,21] April 14eJuly 1 (lo ¼ 14 e100 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 45.7 338.8 0.4 293.3 þ7.9 66.3 þ0.751 þ0.356 0.25 þ0.08 þ0.017 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 14.0 0.595 0.958 163.5 99.3 47.0 146.7 eV 0.0595 0.212 2.52 9.16 8.64 9.16 þ0.0057 0.0014 0.033 þ0.48 þ1.00 þ1.48 N ¼ 21,765 (hr ¼ 29.8 , m(Mv ¼ 0) ¼ 0.02 g) Annual: ZHR ¼ 28/h, B ¼ 0.08  0.014 [17]; variable [11,15] Ave: c ¼ 2.78  0.02 (s ¼ 2.11  0.01), for lo-profile see Fig. 4.4; Peak: CMOR: 2.19  0.14 [12]; Ave: c ¼ 2.7 [17]; 2.4 [20]; 2.26  0.03 [16] Ib: Hb ¼ 112.7  0.42 Mv; Hmax ¼ 105.4 þ 0.93 Mv; He ¼ 100.2 þ 1.30 Mv (21,039) IIb: Hb ¼ 101.8  1.05 Mv; Hmax ¼ 97.5  0.09 Mv; He ¼ 93.1 þ 0.12 Mv (N ¼ 281) III: Hb ¼ 98.9  2.30 Mv; Hmax ¼ 91.1  1.22 Mv; He ¼ 83.3 þ 0.06 Mv (N ¼ 73) r ¼ 0.83  0.35 g/cm3 (N ¼ 1) [18] dNa chondr. Ib: r  0.52  0.04 g/cm3 (a1 ¼ 0.092 km, a2 ¼ 4.77/s), lower if fragile IIb: r w 1.25  0.34 g/cm3 (a1 ¼ 0.084 km, a2 ¼ 6.75/s) dpossibly Na poor III: r w 0.97 g/cm3 (a1 ¼ 0.201 km, a2 ¼ 5.02/s) dpossibly Na free Mg1.16 Fe0.92 Na0.070 (N ¼ 6); Chondritic, anhydrous [13,14] 12,000 y [11]; core from 1400 to 5000 y ago [15]; s (core): w36,000 y 1P/Halley a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.8 0.586 0.967 162.3 111.3 58.4 169.7

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1994-Feb 17.0 TDB

Brief history: Shower first noticed on April 29, 1869, by [1] while cruising the Mediterranean Sea, with “fairly accurate” radiant at R.A. ¼ 329 , Decl. ¼ 2 rising to only 22 elevation before morning twilight set in [1,2]. From observations made in Italy in 1868e1870, [3] later determined a radiant at R.A. ¼ 334 , Decl. ¼ 9 (April 29eMay 6) and named the shower “Aquariads”. Association with 1P/Halley determined in 1876 by [4,5]. Beginning in 1947, eta-Aquariids are observed at Jodrell Bank from R.A. ¼ 339 , Decl. ¼ þ0 [6]. First photographic orbits by [7,8]. By 1912, name was established [9]; Number originated at the Harvard group [10]. Activity curve in Fig. 4.4. Models in [11,16]. 12-y periodicity and occaFIG 4.4 ZHR (•), c profile (o, CMOR x [12]). sional outbursts mostly due to 6:1 mean motion resonance with Jupiter, next in 2023/24, 2045/46, ZHR:120e160 [16]. Magnitude distribution index found to be higher than in [12,19]. Continues beyond this activity period smoothly as shower #372 (PPS, phi Piscids), reversing in radiant drift and spreading in ecliptic latitude. References: [1] Tupman G. L. (1873) MNRAS 33, 301e301; [2] Kronk G. W. (2014) Meteor Showers: An annotated Catalog. Springer, New York, p. 89e94; [3] Denning W. F. (1883) MNRAS 43, 111e114; [4] Hershell A. S. (1876) Rep. Annual Meeting British Assoc. for the Adv. of Sci. 5, 232e235; [5] Hershell A. S. (1878) MNRAS 38, 379e379; [6] Clegg J. A., et al. (1947) MNRAS 107, 373e377; [7] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [8] Lindblad B. A., et al. (1994) PSS 42, 113e116; [9] Olivier C. P. (1912) AJ 27, 639e640; [10] Lindblad B. A. (1990) Documentation of Meteor data available at the IAU meteor data center. Lund: Lund Observatory, 31 pp.; [11] Jenniskens P. (2006) Meteor Showers and their Parent Comets.

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The Atlas: Overview and major showers

May

57

Cambridge: CUP, p. 490e495; [12] Blaauw R. C., et al. (2011) MNRAS 414, 3322e3329; [13] Borovicka J., et al. (2004) EMP 95, 245e253; [14] Rietmeijer F. J. M., Nuth J. A. I. (2000) EMP 82, 325e350; [15] Egal A., et al. (2020) AA 640, A58eA81; [16] Egal A., et al. (2020) AA 642, A120eA147; [17] Jenniskens P. (1994) AA 287, 990e1013; [18] J.-B. Kikwaya Eluo (2011) Bulk Density of Small Meteoroids. PhD Thesis, London: University of Western Ontario, p. 237; [19] Trigo-Rodríguez J. M., Blum J. (2022) MNRAS 512, 2277e2289; [20] Rendtel J. (2021) IMO 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25e25; [21] Ogawa H., Steyaert C. (2017) JIMO 45, 98e106.

May 10 (lo ¼ 50 )

145 ELY d eta Lyrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.59  0.43 Annual shower, perhaps with episodic outbursts May 5e15 (lo ¼ 45 e55 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 50.0 290.9 þ43.7 256.6 þ64.6 43.9 0.16 þ0.04 1.01 þ0.09 0.10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 20.5 1.000 0.951 74.4 191.3 50.0 241.7 eV 1 0.0045 0.0855 1.66 1.60 1.53 1.60 ) 0.0008 þ0.0009 0.23 0.85 þ1.00 þ1.85 1 ) core N ¼ 991 (hr ¼ 54.8 , m(Mv ¼ 0) ¼ 0.06 g) 1.6  0.2/h; 1.7  0.2/h [8]; 2.0  0.2/h [9]; 4.7  1.6/h [10] c ¼ 2.70  0.04 (s ¼ 2.07  0.02); 3.0 [7] Ib: Hb ¼ 106.5  1.26 Mv; Hmax ¼ 96.1 þ 1.32 Mv; He ¼ 91.1 þ 1.77 Mv (N ¼ 513) III: Hb ¼ 95.0  2.37 Mv; Hmax ¼ 87.6  0.43 Mv; He ¼ 83.7  0.25 Mv (N ¼ 25) Ib: r  0.78  0.34 (a1 ¼ 0.063 km, a2 ¼ 5.01/s) dfragmentation, low a2 III: r w 2.6 g/cm3 (a1 ¼ 0.044 km, a2 ¼ 5.51/s) dperhaps Na free or irons Mg1.63 Fe0.94 Na0.168 (N ¼ 1), high Kc ¼ 106 (Na enhanced?) From c and s: w44,000 y; From model: w49,000 y C/1983 H1 (IRAS-Araki-Alcock) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 98.0 0.991 0.990 73.3 192.9 49.1 242.0

Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1983-May-13.0 TDB

Brief history: Parent comet IRASAraki-Alcock had a close encounter with Earth in 1983, when it was discovered. Large nucleus with low activity [11,12]. Shower predicted from orbit of comet by [1]; Grouping of 5 meteors by [2] (only 2 of which were #145) from 3700 photographed orbits during April 21 to May 10; Concentrated grouping of five photographed meteors on date of May 10 first recognized by [3e5]. Activity curve in Fig. 4.5. More info [6, p. 77], and number and name assigned by [6]. References: [1] Drummond J. D. (1983) IAU Circular 3817 (1983 June 1); [2] Terentjeva A. K. (1967) In: Physics and Dynamics of Meteors. Ed.: L. Kresák, P. M. Millman, Dordrecht: D. Reidel, p. 411; [3] Jenniskens P. (1985) Radiant, J. of the DMS 7, 31e33; [4] Ohtsuka K. (1989) Tokyo Meteor Network Rep. 8, 44e49; [5] Ohtsuka K. (1991) Astrophys. Space Sci. Library 173, 315e315; [6] Jenniskens P. (2006) Meteor showers and their Parent Comets, Cambridge: CUP, 790 pp; [7] Rendtel J. (2021) IMO 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25e25; [8] Molau S., et al. (2017) JIMO 45, 144e148; [9] Molau S., et al. (2021) JIMO 49, 47e49; [10] Johannink C., Miskotte K. (2017) eMeteorNews 2, 88e91; [11] Sekanina Z. (1988) AJ 95, 1876e1894; [12] Groussin O., et al. (2010) PSS 58, 904e912. FIG 4.5

ZHR profile.

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The Atlas: Overview and major showers

59

May

May 24 (lo ¼ 63 )

151 EAU d epsilon Aquilids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ 6.61  0.53 Annual shower, part of a ¼ 0.86 AU/i ¼ 60 group April 27eJune 21 (lo ¼ 37 e90 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 69.9 296.1 þ16.2 233.6 þ36.4 30.7 þ0.49 0.54 0.56 0.62 0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.83 0.304 0.625 60.4 325.6 70.0 36.3 eV 0.0882 0.0874 7.75 13.19 12.71 13.19 0.0115y þ0.0116 0.37y þ0.71y þ1.00 þ1.71y w0.2/h (N ¼ 859, hr ¼ 54.5 , m(Mv ¼ 0) ¼ 0.15 g) c ¼ 3.08  0.29 (s ¼ 2.22  0.10) Only deeply penetrating meteoroids: IIb: Hb ¼ 92.8  0.07 Mv; Hmax ¼ 87.6 þ 0.72 Mv; He ¼ 83.4 þ 0.92 Mv (N ¼ 560) dpossibly Na free IIb: r w 1.5 g/cm3 (a1 ¼ 0.065 km, a2 ¼ 6.89/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

May 01eJune 12 (lo ¼ 40 e82 ) lo ( ) R.A. ( ) Decl. ( ) 62.8 281.7 þ0.5 þ0.85 0.22 a (AU) q (AU) e 0.89 0.395 0.770 0.0377 0.1111 0.0029y þ0.0033 0.88 0.191 0.783 N ¼ 11,920

Age: Source:

e e

FIG 4.6

Zenith hourly rate profile.

l ( ) 219.3 0.12 i ( ) 43.0 11.83 0.23 49.9

b ( ) þ23.1 0.28 u ( ) 326.8 6.98 þ0.19y 328.1

Vg (km/s) 29.8 þ0.01 U ( ) 62.8 11.14 þ1.00 81.0

P ( ) 28.3 6.98 þ1.19y 49.1

e R[S] e R[1]

Brief history: Part of the northern #295 June Aquilids Complex (group with #361 [3] and #366). Activity profile in Fig. 4.6. Shower leads up to #164 NZC, the Northern June Aquilids. Strong change of q and e with solar longitude. Shower is strong in video data, but also observed by radar. In agreement with that, the video data show a much lower magnitude distribution index than for #764. First reported from Kharkiv Radar data by [1] from R.A. ¼ 276 , Decl. ¼ þ13 on May 17, 1960. Confirmed from Harvard Meteor Project radar data by [2] with R.A. ¼ 284.3 , Dec ¼ þ15.5 , Vg ¼ 30.8 km/s (B1950.0). Also confirmed from CMOR by [3] and SAAMER by [7]. Seen in video observations by [4] and [5]. Interpreted here to be the broad activity seen moving toward shower #164 NZCd Northern June Aquilids by [5]. Name and number by [6]

References: [1] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 11, 183e199; [2] Sekanina Z. (1976) Icarus 27, 265e321; [3] Brown P., et al. (2010) Icarus 207, 66e81. [4] Kronk G. W. (2014) Meteor Showers, An Annotated Catalog, Second edition, New York: Springer, p. 94e95; [5] Jenniskens P., et al. (2016) Icarus 266, 331e354; [6] Jenniskens P. (2006) Meteor showers and their Parent Comets. Cambridge: CUP, 790 pp; [7] Pokorny P., et al. (2017) Icarus 290, 162e182.

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The Atlas: Overview and major showers

61

June

June 8 (lo ¼ 78 )

171 ARI d Daytime Arietids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density:

Jupiter family comet, sunskirter, part of Machholz Complex, TJ ¼ þ2.12  0.34 Annual shower May 28eJune 19 (lo ¼ 67 e89 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 77.9 44.5 þ24.3 331.1 þ7.1 41.5 þ0.81 þ0.11 0.26 þ0.14 þ0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.82 0.067 0.977 28.3 27.1 77.9 105.2 0.0116 0.0074 3.76 2.09 3.98 2.09 0.0031 þ0.0010 þ0.33 0.64 þ1.00 þ0.36 N ¼ 301 (hr ¼ 12.1 , m(Mv ¼ 0) ¼ 0.07 g) 54  12/h, width ¼ 6.6  2.0 [15]; number influx rate ¼ 0.04 km2 h1 [7]; c ¼ 2.74  0.16 (s ¼ 2.09  0.06); c ¼ 2.7 [15]; 2.8 [17] II: Hb ¼ 99.9 þ 0.04 Mv; Hmax ¼ 96.2 þ 0.66 Mv; He ¼ 91.6 þ 1.29 Mv (N ¼ 200) II: low F ¼ 0.45, fragile (high Ke ¼ 85 km) II: r  3.0 g/cm3 (a1 ¼ 0.127 km, a2 ¼ 2.50/s), lower if fragile

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Median: Dispersion (±s): Drift (d/dlo): Number observed: Mass distribution index:

May 28eJune 23 (lo ¼ 67 e93 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 80.6 46.2 þ26.8 331.3 þ9.0 39.2 þ0.61 þ0.22 0.40 þ0.06 þ0.04 1.97 0.084 0.957 31.1 28.9 80.6 108.8 0.0212 0.0169 5.51 3.71 5.27 3.71 0.0026 þ0.0003 þ0.81 0.58 þ1.00 þ0.42 N ¼ 1132 lo ¼ 67 : s ¼ 2.05, 73 : 1.80, 78 : 1.67, 80.5 : 1.73, 87 : 1.80, 92 : 2.05 [7,16]

Age:

96P captured by Jupiter: w20,000 y [19]; Formation Marsden group 1100e1900 y [11,19]. ARI mostly 10,000e20,000 y [12,19], peak w1300 y [19]. 96P/Machholz 1 3.03 0.123 0.959 58.5 14.7 94.4 109.1 Marsden group of Sunskirter comets; e.g., P/1999 J6 (SOHO) 3.10 0.049 0.984 26.6 21.9 81.6 103.5

Source: Epoch 2008-Nov-03.0 TDB Source: Epoch 2007-Jan-19.0 TDB

eV

e R[M]

Brief history: Daytime activity from Aries and Perseus (R.A. ¼ 52e62 , Decl. ¼ þ15 ) discovered by [1] with radar equipment at Jodrell Bank, U.K., in 1947. Discovery led to publication of [2]. Daytime Arietids and Daytime zeta Perseids separated in 1948 [3]. First orbit determined in 1951 by [4], who noticed similarity to #5 SDA. CMOR determined activity from May 23 to July 1 (lo ¼ 62e99 ), with Vg ¼ 39.1 km/s [5]. Decade long study from CMOR by [7], finding peak at lo ¼ 80.5 and Vg ¼ 40.5  0.7 km/s (after correction for deceleration), also gives summary of past observations. Confirmation from double-station video observations by [6,18]. Link to 96P by [13], confirmed by [12]. Link to Marsden Group of sunskirter comets, and notably P/1999 J6, by [9,10]. Modeling by [11,12]. Called “Filament 1” in model of 96P ejecta by [14]. Name by [1]. Number by [8]. References: [1] Clegg J. A., et al. (1947) MNRAS 107, 374e375; [2] Lovell A. C. B. (1954) Meteor Astronomy. Oxford: Clarendon Press, 463 pp; [3] Aspinall A., et al. (1949) MNRAS 109, 353e354/ 357e358; [4] Almond M. (1951) MNRAS 111, 37e44; [5] Brown P., et al. (2010) Icarus 207, 66e81; [6] Jenniskens P., et al. (2016) Icarus 266, 355e370; [7] Bruzzone J. S., et al. (2015) MNRAS 446, 1625e1640; [8] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [9] Marsden B. G., Seargent D. A. J. (2002) MPEC 2002-E25, Cambridge: MPC, 1 pp; [10] Ohtsuka K., et al. (2003) PASJ 55, 321e324; [11] Sekanina Z., Chodas P. W. (2005) ApJ Sup. Ser. 161, 551e586; [12] Abedin A., et al. (2017) Icarus 281, 417e443; [13] McIntosh B. A. (1990) Icarus 86, 299e304; [14] Neslusan L., et al. (2015) AA 560, A47eA57; [15] Jenniskens P. (1994) AA 287, 990e1013; [16] Blaauw R. C. (2011) MNRAS 414, 3322e3329; [17] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [18] Jenniskens P., et al. (2012) JIMO 40, 98e100; [19] Abedin A., et al. (2018) Icarus 300, 360e385.

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The Atlas: Overview and major showers

June

63

June 14 (lo ¼ 84 )

510 JRC d June rho Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2004-Oct-20.0 TDB

Long-period comet, TJ ¼ þ0.39  0.31 Annual shower June 12e17 (lo ¼ 82 e87 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 84.2 320.8 þ44.4 262.2 þ55.2 49.9 þ1.12 þ0.23 þ0.00 0.00 þ0.10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 18.8 1.007 0.947 88.5 190.9 84.2 274.9 eV 0.0029 0.0898 1.50 1.87 0.86 1.87 þ0.0008 0.0057 þ0.35 0.41 þ1.00 þ0.59 w0.3/h (N ¼ 229, hr ¼ 55.9 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 1.99  0.05 (s ¼ 1.75  0.03) Ib: Hb ¼ 108.9  0.63 Mv; Hmax ¼ 100.3 þ 1.26 Mv; He ¼ 93.1 þ 1.62 Mv (N ¼ 128) Ib: low F ¼ 0.54, fragile meteoroids Ib: r  0.54 g/cm3 (a1 ¼ 0.085 km, a2 ¼ 4.79/s), lower if fragile From c and s: w20,000 y; high dP/dlo vs i; From model: 40,000 y C/2003 T4 (LINEAR) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.850 1.0005 86.8 181.7 93.9 275.6

Brief history: First recognized from Croatian Meteor Network data by [1] from 16 meteors that radiated from R.A. ¼ 321.8 , Decl. ¼ þ43.9 and Vg ¼ 50.2 km/s around lo ¼ 84.2 . Confirmed by [2]. 2003 T4 is unlikely source because orbital period was high P = 265,000 y at 250 AU coming in. Name and number by [1]. References: [1] Segon D., et al. (2013) JIMO 41, 70e74; [2] Jenniskens P., et al. (2016) Icarus 266, 355e370. June 12 (lo ¼ 82 )

458 JEC d June epsilon Cygnids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy: Age:

Long-period comet, TJ ¼ þ0.21  0.36 Annual shower Perhaps in 2008, at 15:41 to 18:31 UT (N ¼ 8, SonotaCo) June 17e28 (lo ¼ 81 e84 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 82.4 315.0 þ33.5 249.0 þ47.8 52.9 þ1.26 þ0.20 0.00 0.00 þ0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 27.6 0.920 0.966 95.7 215.8 82.4 298.4 0.0104 0.0836 1.33 2.46 0.62 2.46 þ0.0034 0.0051 þ0.83 0.63 þ1.00 þ0.37 w0.6/h (N ¼ 303, hr ¼ 55.1 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.13  0.05 (s ¼ 1.82  0.03) Ib: Hb ¼ 109.6  1.17 Mv; Hmax ¼ 100.9 þ 0.89 Mv; He ¼ 95.2 þ 1.61 Mv (N ¼ 173) Ib: r w 0.55 g/cm3 (a1 ¼ 0.064 km, a2 ¼ 4.90/s) Mg0.72 Fe0.76 Na0.044 (N ¼ 2), chondritic From c and s: w24,000 y; high dP/dlo vs i; From model: 32,000 y Earth passes through core of stream (sU < su) e

Source:

eV

Brief history: First recognized in a D-criterion search from early CAMS and SonotaCo data by [1] from R.A. ¼ 314.3 , Decl. ¼ þ33.2 and Vg ¼ 53.2 km/s around lo ¼ 82.3 . Confirmed from EDMOND video observations by [2]. Found also by [3]. Name and number by [1]. References: [1] Rudawska R., Jenniskens P. (2014) In: Meteoroids 2013. Ed.: Jopek T. J., et al., A.M. University, Poznán, p. 217e224; [2] Kornos L., et al. (2014) In: Meteoroids 2013. ibid, p. 225e233; [3] Jenniskens P., et al. (2016) Icarus 266, 355e370.

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The Atlas: Overview and major showers

65

June

July 6 (lo ¼ 104 )

164 NZC d Northern June Aquilids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy:

Jupiter-family comet, Machholz Complex, TJ ¼ þ2.89  0.64 Annual shower June 5eAugust 20 (lo ¼ 73 e148 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 104.1 312.7 2.9 209.1 þ13.1 38.6 þ0.81y þ0.26y 0.13 þ0.02 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) 2.02 0.125 0.940 38.8 325.2 100.6 0.0345 0.0454 6.18 4.39 16.72 þ0.0014 0.0010 0.30 0.22 þ1.00 July 2 (lo ¼ 100 ) 1.3  0.4 [7] (N ¼ 10,146, hr ¼ 46.6 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 3.52  0.15 (s ¼ 2.37  0.05); 4.4 [7] IIb: Hb ¼ 96.4  0.45 Mv; Hmax ¼ 89.7 þ 0.71 Mv; He ¼ 85.0 þ 0.95 Mv IIb: r w 1.42  0.18 g/cm3 (a1 ¼ 0.081 km, a2 ¼ 6.23/s) Mg0.93 Fe0.18 Na0.005 (N ¼ 1), depleted in Fe and Na AMOS: Mg1.00 Fe0.81 Na0.002 (N ¼ 1) [10]

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR:

July 1eAugust 1 (lo ¼ 99 e129 ) lo ( ) R.A. ( ) Decl. ( ) 110.8 321.9 1.1 þ0.94 þ0.21 a (AU) q (AU) e 1.06 0.148 0.866 0.0566 0.0644 0.0005 þ0.0006 0.757 0.173 0.7711 e (N ¼ 29,693)

Age: Source: Orbital elements (J2000.0) Epoch 1994-Feb-17.0 TDB Source: Epoch 1966-Oct-07.0 TDB

12P: 25,000e35,000 [9] C/2009 U10 (SOHO) a (AU) q (AU) N 0.0544 12P/Pons-Brooks 17.0 0.778

P ( ) 69.9 4.39 þ0.78

eV

(N ¼ 7819) dNa poor/free

l ( ) 212.4 0.04 i ( ) 29.9 10.12 0.21 55.4

b ( ) þ13.2 0.11 u ( ) 328.4 8.07 þ0.05 334.9

Vg (km/s) 31.4 0.01 U ( ) 110.8 7.70 þ1.00 105.2

P ( ) 79.8 8.07 þ1.05 80.1

e 1.000

i ( ) 32.2

u ( ) 323.5

U ( ) 100.3

P ( ) 63.8

0.954

74.7

199.1

256.0

95.1

e R[S] e R[1]

duncertain

Brief history: Part of June Aquilids Complex. Long known as a weak visual shower [1] (Shower 201). Detected with Adelaide radar by [2] during June 13e19, 1961. Four meteors radiated from R.A. ¼ 293.9 , Decl. ¼ 8.4 . Again observed by [3] during June 1969. Confirmed from Harvard Radio Meteor Project at Havana, Illinois (USA) by [4]. Detected among photographic observations (N ¼ 19) by [5,6]. Video detection and confusion with Northern delta-Aquariids resolved by [7]. Parent body 2009 U10 by [7] (MPEC 2010-L45). Model by [9] of dust ejecta from 12P/Pons-Brooks has 25,000 year old ejecta with br ¼ 0.000 from R.A. ¼ 300.1  18.3 , Decl. ¼ 7.1  5.0 and Vg ¼ 43.3  5.4 km/s around lo ¼ 103.2  27.7 (“Filament F3”). Name by [4]. Number by [8]. References: [1] McIntosh R. A. (1935) MNRAS 95, 709e718; [2] Nilsson C. S. (1964) AuJP 17, 205e256; [3] Gartrell G., Elford W. G. (1975) AuJP 28, 591e620; [4] Sekanina Z. (1976) Icarus 27, 265e321; [5] Jopek T. J., Froeschlé Cl., (1997) AA 320, 631e641; [6] Jopek T. J., et al. (1999) MNRAS 304, 751e758; [7] Holman D., Jenniskens P. (2012) JIMO 40, 166e170; [8] Jenniskens P. (2006) Meteor showers and their Parent Comets. Cambridge: CUP, p. 490e495; [9] Tomko D., Neslusan L. (2016) AA 592, A107eA118; [10] Matlovic P., et al. (2019) AA 629, A71eA90.

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The Atlas: Overview and major showers

67

July

July 4 (lo ¼ 102 )

165 SZC d Southern June Aquilids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, Machholz Complex, TJ ¼ þ2.48  0.42 Annual shower May 25eJuly 26 (lo ¼ 64 e124 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 101.8 317.4 27.7 208.7 10.7 39.4 þ0.93y þ0.27 0.15 0.04 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.21 0.104 0.954 34.5 148.0 281.8 70.3 eV 0.0382 0.0364 5.02 2.93 11.77 2.93 þ0.0022 0.0003 0.46 0.32 þ1.00 þ0.68 July 8 (lo ¼ 106 ) w1.2/h (N ¼ 3085, hr ¼ 52.1 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 3.52  0.16 (s ¼ 2.37  0.05) II: Hb ¼ 97.1  0.82 Mv; Hmax ¼ 89.8 þ 0.54 Mv; He ¼ 84.9 þ 0.82 Mv (N ¼ 2585) dlikely Na poor/free II: r w 1.84  0.27 g/cm3 (a1 ¼ 0.058 km, a2 ¼ 6.23/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR:

July 17e31 (lo ¼ 114 e128 ) lo ( ) R.A. ( ) Decl. ( ) 123.3 338.9 17.6 þ0.76 þ0.26 a (AU) q (AU) e 1.46 0.084 0.946 0.0536 0.0711 þ0.0008 þ0.0008 1.12 0.064 0.943 e (N ¼ 39,617)

Age: Source:

e (see shower #164)

l ( ) 210.4 0.24 i ( ) 30.5 13.31 0.17 56.0

b ( ) 8.0 0.02 u ( ) 152.9 4.72 0.35 158.6

dcore only Vg (km/s) 37.2 þ0.08 U ( ) 303.7 3.14 þ1.00 260.4

P ( ) 96.4 4.72 þ0.65 97.1

e R[S] e R[1]

Brief history: Part of June Aquilids Complex. Shower first identified in Adelaide radar observations by [1] from R.A. ¼ 297.8 , Decl. ¼ 33.9 and Vg ¼ 33.2 km/s around lo ¼ 80 (their shower 6.08). Confirmed in CMOR radar observations by [2], who added the shower to the list as #370 named “Microscopiids.” [5] detected the shower again, but with several degrees different radiant and 5 km/s different Vg, resulting in more than 20 difference in inclination, perhaps in part due to nearby shower #1129. Video confirmation from CAMS data by [3]. Activity curves for both showers #164 and #165 in Fig. 4.7. Name (being southern branch of shower #164) and number by [4]. FIG 4.7 ZHR profiles of showers #164 and #165.

References: [1] Gartrell G., Elford W. G. (1975) AuJP 28, 591e620; [2] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 490e495; [5] Brown P., et al. (2010) Icarus 207, 66e81.

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The Atlas: Overview and major showers

July

69

July 28 (lo ¼ 126 )

1 CAP d alpha Capricornids

Dynamic type: Shower type: Years of outbursts:

Jupiter-family comet, TJ ¼ 2.99  0.29 Annual shower, with episodic outbursts 1984: lo ¼ 126e131 , ZHR ¼ 5e7/h, low c [21]; 1995: lo ¼ 122e131 [5]; 2002: lo ¼ 124e131 ; 2012: lo ¼ 123.5e132.0 , ZHR ¼ 5/h [18] July 1eAugust 18 (lo ¼ 99 e146 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 125.8 304.8 9.5 179.0 þ9.8 22.7 þ0.61 þ0.24 0.40 þ0.12 0.19 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.74 0.581 0.790 7.7 267.8 126.0 33.6 eV 0.0288 0.067 1.06 3.18 6.76 3.18 þ0.0055 0.0023 0.01 0.63 þ1.00 þ0.37 N ¼ 13,531 (hr ¼ 43.5 , m(Mv ¼ 0) ¼ 0.29 g) 2.2  0.3/h, B ¼ 0.041  0.007 [15]; 3.8  0.3/h [17]; 5/h [20] For lo ¼ 132.5 : c ¼ 1.93  0.02 (s ¼ 1.72  0.01), for lo-dependence: Fig. 4.8; c ¼ 2.0 [15]; Maximum: 2.1  0.1, early and late: w2.5  0.1 [17] Ib: Hb ¼ 97.0  0.87 Mv; Hmax ¼ 87.0 þ 1.06 Mv; He ¼ 83.0 þ 1.36 Mv (N ¼ 8709) IIb: Hb ¼ 85.8  0.37 Mv; Hmax ¼ 80.6 þ 0.70 Mv; He ¼ 76.7 þ 1.10 Mv (N ¼ 164) r ¼ 1.4  0.2 g/cm3, porosity K ¼ 55% [9]; w2.1 g/cm3 (K ¼ 38%) [13] Ib: r w 1.04  0.05 g/cm3 (a1 ¼ 0.0885 km, a2 ¼ 3.98/s) dchondritic Na dNa poor IIb: r w 2.5  0.4 g/cm3 (a1 ¼ 0.078 km, a2 ¼ 5.29/s) Max. dynamic pressure rairV2: 0.005e0.035 MPa [16] dlow Mg0.84 Fe0.88 Na0.037 (N ¼ 6), chondr.; Depleted in Fe, enhanced in Mg [12] 4500e5000 y [6,10]; 2900 y ¼ separation of 169P and P/2003 T12 [11]; Higher rates in 2220e2420 CE, most matter now still inside Earth orbit [6] 169P/NEAT a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.60 0.607 0.767 11.3 218.0 176.2 34.2 2017 MB1 duncertain 2.37 0.589 0.752 8.5 264.7 126.9 32.6 2016 BN14 duncertain 2.37 0.581 0.755 10.1 268.9 127.5 36.4

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Strength: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2007-Dec-30.0 TDB Source: Epoch 2007-Dec-30.0 TDB Source: Epoch 2007-Dec-30.0 TDB

Brief history: In 1871, [1] plotted six meteors from R.A. 305 , Decl. ¼ 4 during July 28e29. In the 1890s, the shower was known to be annual and, in 1899, [2] remarked on the very slow and often bright meteors. Established from 12 photographed meteors by [3]. Detected in Harvard Radio Meteor Project by [4], said to be active from July 30 to September 11. We find that stream has a different magnitude distribution index for meteors brighter than þ0 magnitude in video data. Both values depend on solar longitude (see Fig. 4.8). Because orbit has u w 270 and relatively low e, the shower is visible over 40 in lo [19]. [20] found ZHR rates FIG 4.8 ZHR (•) and c (o) profiles.

70

The Atlas: Overview and major showers

w7/h higher in 1984. Other weak evidence of occasional multiday outbursts of relatively bright meteors by [5,18], every 9.1  0.4 y. Association with 169P/NEAT by [6], confirmed by [7]. C/2003 T12 (SOHO) seems to be a fragment of 169P, responsible for related shower #623. Alternative scenario by [8], who identified asteroid 2017 MB1 as having a nodal line more similar to the current a-Capricornid orbit. 2016 BN14 may be fragment of 2017 MB1, according to [14]. Semi-major axis and radiant of showers favor 169P. Shower number and name by [3]. References: [1] de Konkoly N. (1880) MNRAS 40, 349e363; [2] Denning W. F. (1899) Mem. RAS 53, 203e292; [3] Wright F. W., et al. (1956) AJ 61, 61e69; [4] Sekanina Z. (1973) Icarus 18, 257e259; [5] McBeath A. (1996) JIMO 24, 68e69; [6] Jenniskens P., Vaubaillon J. (2010) AJ 139, 1822e1830; [7] Kasuga T., et al. (2010) AJ 140, 1806e1813; [8] Ye Q.-Z., et al. (2018) AJ 155, 163e176; [9] Narziev M. (2019) PSS 173, 42e48; [10] Kasuga T., Balam D. D., Wiegert P. A. (2010) AJ 140, 1806e1813; [11] Sosa A., Fernández J. A. (2015) IAU General Assembly 29, Abstract id.2255583; [12] Madiedo J. M., et al. (2014) Icarus 239, 273e280; [13] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [14] Guennoun M., et al. (2019) AA 622, A84eA93; [15] Jenniskens P. (1994) AA 287, 990e1013; [16] Shrbeny L., Spurny P. (2019) AA 629, A137eA147; [17] Molau S., et al. (2019) JIMO 47, 116e120; [18] Molau S., et al. (2012) JIMO 40, 181e186; [19] Koseki M. (2012) JIMO 40, 162e165; [20] Miskotte K., Johannink C. (2012) JIMO 40, 87e90; [21] Miskotte K., Johannink C. (2008) JIMO 36, 37e42.

July

71

July 20 (lo ¼ 118 )

623 XCS d xi2 Capricornids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ 2.95  0.22 Annual shower July 15e27 (lo ¼ 102 e129 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 118.4 301.4 11.5 184.4 þ8.6 25.9 þ0.76 þ0.20 0.22 þ0.05 0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.65 0.486 0.816 8.1 278.8 116.6 35.3 eV 0.0228 0.054 0.93 1.78 5.69 1.78 þ0.0044 0.0019 0.03 0.48 þ1.00 þ0.52 w0.3/h (N ¼ 930, hr ¼ 42.3 , m(Mv ¼ 0) ¼ 0.22 g) c ¼ 2.88  0.21 (s ¼ 2.15  0.08) Ib: Hb ¼ 98.1  0.85 Mv; Hmax ¼ 87.6 þ 1.18 Mv; He ¼ 83.6 þ 1.18 Mv (N ¼ 739) IIb: Hb ¼ 90.0  1.47 Mv; Hmax ¼ 83.5 þ 0.38 Mv; He ¼ 80.2 þ 0.34 Mv (N ¼ 28) Ib: r w 0.76  0.13 g/cm3 (a1 ¼ 0.171 km, a2 ¼ 3.10/s) IIb: r w 2.5  1.3 g/cm3 (a1 ¼ 0.075 km, a2 ¼ 7.53/s) dpossibly Na poor e; sU > su: radiant drift C/2003 T12 (SOHO) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.57 0.575 0.776 11.5 217.7 176.5 34.2

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2012-May-25.0 TDB

Brief history: First recognized as a component separate from the alpha Capricornids by [1] from radiant at R.A. ¼ 303.9 , Decl. ¼ 10.8 and Vg ¼ 24.5 km/s around lo ¼ 120.0 . Shower has steeper magnitude size distribution index for meteors fainter than þ0: c ¼ 3.67 (s ¼ 2.41); brighter: c ¼ 1.76 (s ¼ 1.61). Source comet identified by [1], with theoretical radiant at R.A. ¼ 305.0 , Decl. ¼ 10.1 and Vg ¼ 23.0 km/s. Number and name by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354. July 31 (lo ¼ 128 )

5 SDA d Southern delta Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Number detected: Peak ZHR:

Jupiter-family comet, Machholz Complex, TJ ¼ 2.35  0.58 Annual shower July 15eAugust 30 (lo ¼ 113 e157 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 127.6 340.6 16.2 208.4 7.6 40.6 þ0.81 þ0.21 0.17 0.11 0.19 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.59 0.078 0.970 27.5 151.1 307.6 98.8 eV 0.0218 0.0194 7.63 3.90 5.22 3.90 þ0.0030 0.0014 0.24 0.51 þ1.00 þ0.49 July 29: lo ¼ 126.5 (good activity during 124 e129 ) N ¼ 74,388 (hr ¼ 44.8 , m(Mv ¼ 0) ¼ 0.07 g) var.; 26  3/h [27]; 11.4  1.2/h [22]; 13  2/h [14]; ZHR ¼ 28/h, Flux ¼ 0.031 km2 h1 [25]; 11e36/h [26]; Incoming mass: 3  1 kg/activity period [23] c ¼ 3.36  0.04 (s ¼ 2.32  0.02); 3.3 [22]; Max: 2.5, early: 3.4, late: 3.0 [14] Ia: Hb ¼ 114.5  0.86 Mv; Hmax ¼ 100.2 þ 2.43 Mv; He ¼ 90.2 þ 1.84 Mv (N ¼ 193) II: Hb ¼ 97.6  0.39 Mv; Hmax ¼ 91.9 þ 0.78 Mv; He ¼ 87.2 þ 1.21 Mv (N ¼ 32,637) IIb: Hb ¼ 96.6  0.67 Mv; Hmax ¼ 88.3 þ 1.25 Mv; He ¼ 82.5 þ 1.48 Mv (N ¼ 24,145) IV: Hb ¼ 84.4  0.59 Mv; Hmax ¼ 79.8  0.63 Mv; He ¼ 75.3  1.44 Mv (N ¼ 67) r ¼ 3.5  0.3 g/cm3, porosity K ¼ 7% [16], 2.4  0.6 g/cm3, 29% [17] Ia: r < 0.19 g/cm3 (a1 ¼ 0.343 km, a2 ¼ 2.40/s); F ¼ 0.59: fragile II: r w 1.24  0.08 g/cm3 (a1 ¼ 0.083 km, a2 ¼ 5.67/s) dNa chondritic to poor IIb: r w 1.70  0.09 g/cm3 (a1 ¼ 0.059 km, a2 ¼ 8.53/s) dNa free

Magn. distribution index: Lightcurve:

Meteoroid density:

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The Atlas: Overview and major showers

July

73

July 31 (lo ¼ 128 )

5 SDA d Southern delta Aquariids (cont.)

Strength: Spectroscopy: Age:

Max. dynamic pressure rairV2 ¼ 0.075 MPa (0.04e0.11 MPa) [24] Mg1.04 Fe0.62 Na0.002 (N ¼ 9), Na depleted 96P captured by Jupiter: w20,000 y [19]; Formation Marsden group 1100e1900 y [13,28] SDA mostly 96P 12,000 y [18]; Peak: 1300 y [13,28] 96P/Machholz 1 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.03 0.123 0.959 58.5 14.7 94.4 109.1 Kracht group of Sungrazers, e.g., 342P/SOHO 3.04 0.053 0.982 13.3 58.7 43.4 102.1

Source: Orbital elements (J2000.0) Epoch 2008-Nov-03.0 TDB Source: Epoch 2016-Jul-31.0 TDB

Brief history: First observed as a minor visual shower in 1849 by J. F. J. Schmidt. 23 Meteors during August of 1858e1863 radiated from R.A. ¼ 337 , Decl. ¼ 10 [1]. In 1870, [2] put the radiant correctly at R.A. ¼ 340 , Decl. ¼ 14 on July 27 and R.A. ¼ 340 , Decl. ¼ 19 on July 28. Frequently seen visually in 1869e1898 by [3]. First photographed orbits by [4,5]. Name and number by [6]. Radar detection by [7] in 1950. Video detection by [8]. Activity curve in Fig. 4.9. Confirmed as a very strong radar shower by [9]. Visual data presented in [10]. [21] identified shower #640 as broader underlying component, dominant for lo > 132 . Link to 96P by [19]. Link to Machholz family comets by [10,13], closest in terms of rotation of the nodal line to Kracht group of Sungrazers. Kracht group resulted from ongoing fragmentation cascade in last few centuries [15]. Models by [11e13]. [20] model “Filament 5.” FIG 4.9 ZHR profile (•). References: [1] Heis E., Neumayer G. (1867) On Meteors in the Southern Hemisphere. Mannheim: J. Schneider, 25pp; [2] Tupman G. L. (1873) MNRAS 33, 300e307; [3] W. F. Denning (1899) MNRAS 53, 203e292; [4] Wright F. W., et al. (1957) Harvard Reprint Ser. II 108, 225e233; [5] Whipple F. L. (1957) AJ 62, 225e233; [6] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [7] McKinley D. W. R. (1954) AJ 119, 519e530; [8] Jopek T. J., Froeschlé Cl. (1997) AA 320, 631e641; [9] Galligan D. P. (2003) MNRAS 340, 899e907; [10] Ohtsuka K., et al. (2003) PASJ 55, 321e324; [11] Hamid S. E., Whipple F. L. (1963) AJ 68, 537e537; [12] Williams I. P., Murray C. D. (1979) MNRAS 189, 483e492; [13] Sekanina Z., Chodas P. W. (2005) AJSS 161, 551e586; [14] Johannink C., Miskotte K. (2012) JIMO 40, 65e68; [15] Battams K., Knight M. M. (2020) Philosoph. Trans. A 375, 20160257; [16] Narziev M. (2019) PSS 173, 42e48; [17] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [18] Abedin A., et al. (2017) Icarus 281, 417e443; [19] McIntosh B. A. (1990) Icarus 86, 229e304; [20] Neslusan L., et al. (2015) AA 560, A47eA57; [21] Jenniskens P., et al. (2016) Icarus 266, 331e354; [22] Jenniskens P. (1994) AA 287, 990e1013; [23] Trigo-Rodríguez J. M., Blum J. (2022) MNRAS 512, 2277e2289; [24] Shrbeny L., Spurny P. (2019) AA 629, A137eA146; [25] Molau S., et al. (2019) JIMO 47, 116e120; [26] Molau S., et al. (2015) JIMO 43, 188e194; [27] Miskotte K. (2018) eMeteorNews 3, 14e18; [28] Abedin A., et al. (2018) Icarus 300, 360e385.

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The Atlas: Overview and major showers

August

75

Aug. 13 (lo ¼ 140 ) 7 PER d Perseids Dynamic type: Long-period comet shower from Halley-type comet, TJ ¼ 0.01  0.42 Shower type: Annual shower, occasional outbursts Years of outbursts (partial list): 1861: 139.9 [1] e 1479 dust trail or older Filament component (Fil) e Fil 1862: 139.61 , W > 0.3 [1] 1863: 139.64 , W ¼ 0.5 [1] e Fil 1989: 139.58 0.03 , ZHR ¼ 70  15/h, W ¼ 15 [1] e Fil e 1610 or Fil 1990: 139.57  0.02 , ZHR ¼ 150  75/h, W ¼ 0.043 [1] 1991: 139.564  0.005 , 350  75/h, W ¼ 0.034  0.006 , c ¼ 1.96 [1] e 1610 or Fil 1992: 139.453  0.001 , 550  150/h, W ¼ 0.054 , c ¼ 2.05  0.05 [1] e 1862 or Fil 1993: 139.445  0.02 , 250  35, W ¼ 0.109  0.015 , c ¼ 1.72  0.02 [1] e 1862 or Fil e Fil 1994: 139.57  0.02 , 190  30/h, W ¼ 0.043 , c ¼ 1.82  0.05 [1] 1995: 139.66  0.02 , ZHR ¼ 120  25/h, W ¼ 0.041 [1] e Fil 1996: 139.64  0.03 , ZHR ¼ 100  40/h, W ¼ 0.059  0.013 [1] e Fil 1997: 139.72  0.03 , ZHR ¼ 137  7/h [1] e Fil e Fil 1998: 139.75  0.03 , ZHR ¼ 110  20/h [29] 1999: 139.793  0.004 , ZHR ¼ 20  3/h, W ¼ 0.043  0.015, c < 2.1 [1] e Fil 2004: 139.44  0.01 , ZHR ¼ 130/h, W ¼ 0.05  0.01 e 1862 e Fil 139.63  0.01 , ZHR ¼ 60  10/h, W ¼ 0.15  0.02 [1] 2013: 136.261e137.442 ; c ¼ 3.58  0.24 [24] e? 2016: 136.460 ; ZHR ¼ 320  15/h, c ¼ 2.12 [21,29] e 1079 2018: w139.77 ; ZHR w 64  13/h, c ¼ 1.75 [23] e Fil e? 2021: 141.474  0.005 ; 130  20/h, W ¼ 0.08  0.02 , c ¼ 2.09 [22,31] Period of activity: July 18eSeptember 18 (lo ¼ 115 e175 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) Shower radiant/speed lo ( ) 1 Median (geocentric): 140.1 47.9 þ57.9 283.0 þ38.4 58.8 ) 2 Drift per day (d/dlo): þ1.45 þ0.20 þ0.02 0.08 þ0.03 ) Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Median: 12.7 0.949 0.925 113.0 150.3 140.07 290.4 eV 1 Dispersion (±s): 0.0236 0.1527 2.82 6.12 0.80 6.04 ) 1 0.00169 þ0.00344 þ0.022 0.333 þ1.00 þ0.667 ) Drift (d/dlo): Median: 12.9 0.947 0.927 112.4 149.7 136.2 285.4 eV 2 Dispersion (±s): 0.0275 0.1570 3.81 6.75 7.54 6.75 ) 2 Drift (d/dlo): 0.00083 0.00150 þ0.100 0.145 þ1.00 þ0.855 ) 1 ) core: lo ¼ 138.3e141.7 ; 2) other Number observed: N ¼ 141,260 (hr ¼ 47.0 , m(Mv ¼ 0) ¼ 0.03 g) Peak ZHR: 1980e1990: ZHR ¼ 84  5/h, includes core 70  5/h and bkg 23  2/h [18] 1991e1994: ZHR ¼ 86  2 [1]; 2020: ZHR ¼ 77e125/h [31] Incoming mass: 150  45 kg/activity period [19] Magn. distribution index: Peak: c ¼ 2.36  0.03 (s ¼ 1.93  0.01); c ¼ 2.36  0.05 [1]; Ave: 2.5 [18] Peak: s ¼ 1.54  0.09 [31] Lightcurve: Ia: Hb ¼ 114.5  2.16 Mv; Hmax ¼ 102.3 þ 1.57 Mv; He ¼ 96.9 þ 2.11 Mv (N ¼ 22,577) Ib: Hb ¼ 108.9  1.55 Mv; Hmax ¼ 100.9 þ 1.00 Mv; He ¼ 96.2 þ 1.45 Mv (N ¼ 36,593) III: Hb ¼ 97.5  0.65 Mv; Hmax ¼ 91.9 þ 0.43 Mv; He ¼ 87.1 þ 0.63 Mv (N ¼ 521) Meteoroid density: r ¼ 1.0  0.2 g/cm3, porosity K ¼ 57% [11]; 1.2  0.2, 45% [14]; r ¼ 0.66  0.22 (N ¼ 7) [32] Ia: core: r  1.07 g/cm3 (a1 ¼ 0.010 km, a2 ¼ 2.89/s), fragmentation: low a2 Ia: before core: r w 1.0 g/cm3 (a1 ¼ 0.009 km, a2 ¼ 3.71/s) Ia: after core: r w 0.49  0.05 g/cm3 (a1 ¼ 0.086 km, a2 ¼ 4.35/s) Ib: r w 0.60  0.04 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 7.63/s) dNa poor dpossibly Na free III: r w 2.09  0.28 g/cm3 (a1 ¼ 0.045 km, a2 ¼ 9.85/s) Strength: Max. dynamic pressure rairV2 ¼ 0.030 MPa (0.003e0.067 MPa) [20] Spectroscopy: Mg0.70 Fe0.72 Na0.038 (N ¼ 94), chondritic, relatively strong O emissions that lowers all three numbers; AMOS: Mg1.00 Fe0.79 Na0.046 (N ¼ 28) [30]; Depleted in Fe, Cr, Mn, enhanced in Si, Na [12,13] Age: main peak: 5000 y [10]; 15,000e20,000 y [16]; From c: w20,000 y bkg: 145 w0.9/h (N ¼ 4502, hr ¼ 57.8 , m(Mv ¼ 0) ¼ 0.33 g) c ¼ 2.36  0.07 (s ¼ 1.93  0.03) Ia: Hb ¼ 109.3  3.08 Mv; Hmax ¼ 97.3 -1.36 Mv; He ¼ 88.4  0.10 Mv (N ¼ 66) Ib: Hb ¼ 96.4  1.15 Mv; Hmax ¼ 84.8 þ 1.32 Mv; He ¼ 80.1 þ 1.77 Mv (N ¼ 2144) III: Hb ¼ 86.2 þ 0.07 Mv; Hmax ¼ 80.7 þ 0.86 Mv; He ¼ 76.9 þ 1.11 Mv (N ¼ 249) r ¼ 3.15  0.50 g/cm3 (N ¼ 1) [7] Ia: r w 0.59 g/cm3 (a1 ¼ 0.140 km, a2 ¼ 2.28/s) dNa enhanced Ib: r w 1.39  0.14 g/cm3 (a1 ¼ 0.090 km, a2 ¼ 3.01/s) dpossibly Na poor/free III: r w 2.19  0.34 g/cm3 (a1 ¼ 0.169 km, a2 ¼ 3.96/s) lb:Mg0.91 Fe0.86 Na0.048 (N ¼ 2), chondritic e 361861 (2008 ED69) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.91 0.759 0.739 36.4 173.3 149.5 322.8 2021 HK12 duncertain 3.284 1.036 0.684 47.0 168.8 187.1 355.9

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2021-Jul-01.0 TDB Source: Epoch 2021-Jul-01.0 TDB

Brief history: Radiant and velocity drifts with solar longitude are not linear but V-shaped (Fig. 4.11). Shower often confused with nearby #12, the kappa Cygnids. [1] first isolated the stream from photographed orbits and called it “zeta Draconids” from R.A. ¼ 269 , Decl. ¼ þ59 and Vg ¼ 24 km/s during August 20e25. [2] distinguished in addition to the kappa Cygnids also the “Zeta Draconids” (shower #197) and “August Lyrids” (southern part of #197). #197 detected in single-station video data by [9]. Clear separation between #12 and #197 among triangulated orbits was by [3]. [8] described #197 as consisting of two showers before and after lo ¼ 150 , but that is not confirmed here. Name and number FIG 4.11 Polar radiant map of #12 and #197. by [4]. Possible source 2008 ED69 identified by [5]. Possible source 2021 HK12, proposed here, is better aligned with orbital elements. 2002 LV and 2001 MG1 are other possible parent bodies, while [6] proposed 1983 SA. References: [1] Lindblad B. A. (1971) SCoA 12, 14e24; [2] Lindblad B. A. (1995) EMP 68, 397e404; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 709 pp; [5] Jenniskens P., Vaubaillon J. (2008) AJ 136, 725e730; [6] Rudawska R., Vaubaillon J. (2015) PSS 118, 25e27; [7] J.-B. Kikwaya Eluo (2011) Bulk Density of Small Meteoroids. PhD Thesis, London: UWO, p. 237; [8] Koseki M. (2020) JIMO 48, 130e137; [9] Molau S., Rendtel J. (2009) JIMO 37, 98e121.

80

The Atlas: Overview and major showers

September

81

Sep. 1 (lo ¼ 159 )

206 AUR d Aurigids

Dynamic type: Shower type: Years of outbursts:

Long-period comet, TJ ¼ 0.62  0.38 Annual shower, episodic outbursts 1935: lo  158.664, 1986: lo ¼ 158.518, 1994: 158.70  0.02, W ¼ 0.019 [4], 2007: lo ¼ 158.558 , ZHR ¼ 132  26/h, W ¼ 0.75 h; c ¼ 1.74  0.08 [10,17], 2019: lo ¼ 157.918 , ZHR ¼ 62  12/h, c ¼ 2.5  0.1 [5,10] 2021: lo ¼ 158.39  0.02 , ZHR ¼ 85  27/h, c ¼ 1.9  0.2 [13,14] August 14eSeptember 19 (lo ¼ 141 e177 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 158.9 91.7 þ39.3 292.4 þ16.1 65.7 þ1.15 þ0.10 0.07 þ0.12 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 22.3 0.677 0.969 148.0 109.4 158.9 268.7 eV 1 0.0331 0.0942 1.45 5.74 7.43 5.74 ) þ0.0023 0.0008 0.21 þ0.29 þ1.00 þ1.29 1 ) annual N ¼ 1067 (hr ¼ 39.2 , m(Mv ¼ 0) ¼ 0.02 g) Annual: c ¼ 2.9  0.1/h [16]; 9  3/h, B ¼ 0.19  0.04 [11]; 10  1/h [12] Annual: 2.79  0.02 (s ¼ 2.11  0.01); c ¼ 2.7 [11]; c ¼ 2.5 [10,12] Ib: Hb ¼ 112.6  1.61 Mv; Hmax ¼ 103.0 þ 1.19 Mv; He ¼ 98.3 þ 1.63 Mv (N ¼ 459) III: Hb ¼ 100.7  0.40 Mv; Hmax ¼ 96.8  0.44 Mv; He ¼ 92.3  0.03 Mv (N ¼ 13) Ib: r w 0.69  0.32 g/cm3 (a1 ¼ 0.064 km, a2 ¼ 5.69/s) III: r w 3.1 g/cm3 (a1 ¼ 0.032 km, a2 ¼ 16.08/s) dpossibly Na free Na0.063 (N ¼ 2), chondritic w2000 y for outbursts [8]; Annual: c: w42,000 y, Tail (s): w56,000 y; Model: 78,000 y C/1911 N1 (Kiess) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 183.7 0.684 0.996 148.4 110.4 158.7 269.1

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1911-Jul-30.0 TDB

Brief history: Shower first noticed during an outburst in 1935, observed by two separate teams of experienced observers at the Sonneberger Sternwarte (Germany) and the Stefanik Observatory (Czech Rep.) [1,2]. Association with C/1911 N1 by [1] based on radiant position. Unexpected 1986 outburst observed in Hungary by experienced visual observer [3], who plotted meteors from common radiant position at R.A. ¼ 90.5 , Decl. ¼ þ34.6 . Bright 3 to þ3 magn. meteors. Anticipated 1994 outburst documented by visual observers in southern California and by radio forward meteor scatter from Finland [4,5], demonstrating that Sun’s reflex motion mimics dust trail motion at Earth [6]. Model by [7,8] and predicted outburst in 2007 FIG 4.12 ZHR profile for 2020. observed from air and ground [9]. Activity in 2019 explained by [10], adding the predictions for 2021 that were confirmed by [13e15]. Annual activity established from video observations (Fig. 4.12). Name by [1], number by [4]. References: [1] Teichgraeber A. (1935) Sterne 15, 277e277; [2] Guth V. (1936) AN 258, 27e28; [3] Tepliczky I. (1987) JIMO 15, 28e29; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 723; [5] Zay G., Lunsford R. (1994) JIMO 22, 224e226; [6] Jenniskens P. (1995) AA 317, 953e961; [7] Jenniskens P., Vaubaillon J. (2007) JIMO 35, 30e34; [8] Lyytinen E., Jenniskens P. (2003) Icarus 162, 443e452; [9] Jenniskens P., Vaubaillon J. (2007) EOS 88, 317e318; [10] Rendtel J., Lyytinen E., Vaubaillon J. (2020) JIMO 48, 158e162; [11] Jenniskens P. (1994) AA 287, 990e1013; [12] Rendtel J. (1990) JIMO 18, 81e84; [13] Hiroshi O, Sugimoto H. (2021) eMeteorNews 6, 574e577; [14] Miskotte K. (2021) eRadiant 6, 526e530; [15] Rendtel J., Koschack R. (2021) JIMO 49, 73e75; [16] Molau S., et al. (2019) JIMO 47, 160e162; [17] Rendtel J. (2007) JIMO 35, 108e112.

82

The Atlas: Overview and major showers

September

83

Sep. 14 (lo ¼ 172 )

757 CCY d chi Cygnids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.91  0.45 Episodic shower 2010, 2015, 2020 July 22eSeptember 25 (lo ¼ 120 e182 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 172.2 300.5 þ32.4 141.4 þ51.4 14.9 1 0.44 þ1.09 1.03 þ1.16 0.00 ) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.79 0.953 0.660 18.1 209.6 172.2 21.6 eV 0.0086 0.0882 2.21 2.58 13.15 2.58 1 þ0.0038y 0.0017 þ0.29y 1.00 þ1.00 0.00 ) 1 N ¼ 1639 (hr ¼ 55.9 , m(Mv ¼ 0) ¼ 0.66 g) ) core lo > 158 var.; 2020: ZHR ¼ 2.4  0.1 [6]; 2015: ZHR ¼ 3.2  0.3/h [8] c ¼ 3.11  0.05 (s ¼ 2.23  0.02); c w 3 [6] Ib: Hb ¼ 93.1  0.90 Mv; Hmax ¼ 84.3 þ 1.19 Mv; He ¼ 80.0 þ 1.61 Mv (N ¼ 1294) IIb: Hb ¼ 83.3  0.53 Mv; Hmax ¼ 79.3 þ 0.00 Mv; He ¼ 75.7 þ 0.42 Mv (N ¼ 112) F ¼ 0.65 Ib: r w 1.34  0.24 g/cm3 (a1 ¼ 0.129 km, a2 ¼ 2.59/s) dpossibly Na poor/free IIb: r w 2.5  0.6 g/cm3 (a1 ¼ 0.116 km, a2 ¼ 4.54/s) e 2020 RF duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.60 1.008 0.612 18.3 204.6 175.6 20.2

Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2021-Jul-01.0 TDB

Brief history: First recognized from five orbits in CAMS BeNeLux data by C. Johannink and M. Breukers in night of 2015 September 14/15 [1]. Confirmed from SonotaCo observations by [2]. Confirmation from EDMOND, IMO VMN, and BRAMON low-light video observations by [3] between lo ¼ 165.6 and 174.5 (September 8e17), showing strong activity also in 2010. Detected as a possible shower from 1999 to 2011 VMN single station video data by [9], recalculated with extended range including 2015 data by [8]. Again observed by CAMS networks in 2020 during August 5 to September 25, with early detections motivating the issue of an outburst alert [4]. Shower activity shows gradual rise (Fig. 4.13), FIG 4.13 ZHR profile for 2020. with radiant emerging from the anthelion source and abrupt ending at high ecliptic latitude. Video and visual observations of the 2020 return by [5-7]. Possible source 2020 RF by [5]. Name and number by [1]. References: [1] Jenniskens P. (2015) CBET 4144, Ed.: D.W.E. Green, Cambridge: CBAT (issued 2015 September 17); [2] Shiba Y. (2015) JIMO 43, 179e180; [3] Koukal J., Srba J., Tóth J. (2016) JIMO 44, 5e9; [4] Jenniskens P. (2020) eMeteorNews 5, 287e289; [5] Jenniskens P. (2020) JIMO 48, 146e149; [6] Miskotte K. (2021) eMeteorNews 6, 540e542; [7] Gaarder K. (2021) eMeteorNews 6, 52e53; [8] Molau S., et al. (2016) JIMO 44, 21e26; [9] Molau S., et al. (2012) JIMO 40, 207e212.

84

The Atlas: Overview and major showers

October

Oct. 1 (lo ¼ 188 )

221 DSX d Daytime Sextantids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve:

Asteroid, Phaethon Complex, TJ ¼ þ5.05  0.45 Annual shower, perhaps with episodic outbursts 1957, 1961, 1969, 1988, (2005) 2011, (2014) 2016, 2019/2020 September 20eOctober 12 (lo ¼ 177 e198 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 188.4 156.2 2.7 330.1 11.7 32.5 þ0.82 0.44 0.06 0.11 0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.12 0.144 0.870 25.5 212.8 9.0 221.8 0.0225 0.0292 4.61 3.15 3.39 3.15 þ0.0006 0.0009 þ0.17 þ0.02 þ1.00 þ1.02 N ¼ 748 (hr ¼ 15.0 , m(Mv ¼ 0) ¼ 0.12 g) October 2 (lo ¼ 189.0 ); lo ¼ 188.35  0.10 [7] w5/h; 0e30/h, FWHM ¼ 2.0  0.2 [7]; w50/h [17]; 20/h [18] 2.99  0.10 (s ¼ 2.19  0.03); 2.5 [16]; 2.6e2.7 [17]; s ¼ 1.64  0.06 peak [18] Component IIa has high end height, Ke > 82 due to shallow entry angle: IIa: Hb ¼ 99.6  0.47 Mv; Hmax ¼ 93.0 þ 0.40 Mv; He ¼ 89.1 þ 0.74 Mv (N ¼ 203) IIa: r w 2.36  0.48 g/cm3 (a1 ¼ 0.124 km, a2 ¼ 2.26/s) w25,000 y (>10,000 y) [14] (155140) 2005 UD a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.27 0.163 0.872 28.7 207.6 19.7 227.3

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2021-Jul-01.0 TDB

85

eV

Brief history: Discovered by [1] from University of Adelaide one-aerial radar observations in 1957, calling it the “Sextantids-Leonids”, radiant at 155  8 , Decl. ¼ 0  10 during September 26 to October 4. Peak rate of 30 echoes per hour during September 29 to October 3. Confirmed by [2] (Shower 61.9.2) from 9 meteors during September 24e29, 1961, with radiant at R.A. ¼ 151.7 , Decl. ¼ 0.1 , now calling it “the Sextantid meteor stream”. Pointed out similarity between Sextantid and Geminid orbits, suggesting daytime return of Geminids. However, Sextantids had different duration and perhaps not detected annually. Not detected by [3] and [4]. Nine members detected by Harvard Radio Meteor Project during October 7e9, 1969 [5]. Forward meteor scatter detection by [6] in 1988. Solid radar detection by [7], with [8] putting peak at lo ¼ 187.5 . Confirmed by CAMS low-light video observations, with yearly count starting in 2007 (reflecting increase of cameras deployed in 2019 and 2020): 0, 5, 2, 4, 27, 10, 16, 24, 18, 33, 17, 17, 78, 40, 46, 52. Frequency suggests a periodicity of 4.54  0.02 years. Nearest resonance of 2005 UD with Jupiter is 4.45 years (3:8). Activity profile by [9,18]. 2005 UD identified as parent body shortly after its discovery by [10,11], pointing out the object may be a member of a Phaethon complex. [12] noted that the surface colors of 2005 UD are similar to those of 3200 (Phaethon), but recent near-IR reflectance studies show differences that suggest that Phaethon’s surface was heated more than that of 2005 UD [13]. Model by [14] implies higher age w10,000 y for Sextantids than that of Phaethon’s Geminids w1000 y, but [15] pointed out 2005 UD still has node similar to Sextantids. [18] found mass in stream 1016 g, similar to that of 2005 UD, typical of other parent body fragmentation cases [15]. Name by [2], number by [15]. References: [1] Weiss A. A. (1960) MNRAS 120, 387e403; [2] Nilsson C. S. (1964) AuJP 17, 158e160; [3] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [4] Sekanina Z. (1973) Icarus 18, 253e284; [5] Sekanina Z (1976) Icarus 27, 265e321; [6] Artoos D. (1988) JIMO 17, 49e50 [7] Galligan D. P., Baggaley W. J. (2002) In: Dust in the Solar System and Other Planetary Systems. Eds.: S. F. Green, et al., Oxford: Pergamon, pp. 54e58; [8] Brown P., et al. (2008) Icarus 195, 317e339; [9] Ohtsuka K., et al. (1997) EMP 77, 83e91; [10] Ohtsuka K., et al. (2005) CBET 283, D.W.E. Green ed. (CBAT: 2005 November 11); [11] Ohtsuka K., et al. (2006) AA 450, L25eL28; [12] Kinoshita D., et al. (2007) AA 466, 1153e1158; [13] Kareta T., et al. (2021) The Plan. Science J. 2, 190e202; [14] Jakubik M., Neslusan L. (2015) MNRAS 453, 1186e1200; [15] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, Ch. 22; [16] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [17] Molau S., et al. (2015) JIMO 43, 28e32; [18] Kipreos Y., et al. (2022) MNRAS 516, 924e941.

86

The Atlas: Overview and major showers

October

Oct. 23 (lo ¼ 210 )

87

8 ORI d Orionids

Long-period comet shower from Halley-type comet, TJ ¼ 0.37  0.71 Annual shower, episodic outbursts 1993: lo ¼ 204.5, ZHR ¼ 25  5/h, W ¼ 1.0  0.2 , c ¼ 1.7 [10,17] 1997e1998: ZHR w 40/h (from model only) [22] 2005e2012: lo ¼ 208.6  0.1, ZHR w 50/h, c ¼ 1.58  0.08 [22,30,31] 2006: lo ¼ 207.88, ZHR ¼ 43/h, c ¼ 1.6 [18]; R.A. ¼ 95.1 , Decl. ¼ þ15.5 [29] Period of activity: October 12eNovember 18 (lo ¼ 198 e236 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) Shower radiant/speed lo ( ) Median (geocentric): 209.5 96.3 þ15.7 246.5 7.6 66.1 Drift per day (d/dlo): þ0.78 þ0.03 0.24 þ0.07 0.06 Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Median: 10.5 0.567 0.959 163.9 83.5 29.5 113.2 eV 1 Dispersion (±s): 0.0387 0.0853 1.77 6.98 4.11 6.98 ) Drift (d/dlo): 0.0071 þ0.0008 þ0.07 þ0.81 þ1.00 þ1.81 Median (2006 Filament): 14.8 0.603 0.959 163.71 78.7 27.42 106.1 e [29] 2 Dispersion (±s): 0.003 0.003 0.14 0.4 0.03 0.4 ) 1 Number observed: N ¼ 62,224 (hr ¼ 48.5 , m(Mv ¼ 0) ¼ 0.02 g) ) core; 2) fireballs Peak ZHR: ZHR ¼ 23/h [24]; ZHR ¼ 25  4, B ¼ 0.12  0.02 [25] Magn. distribution index: lo ¼ 207 : c ¼ 2.56  0.06 (s ¼ 2.02  0.02) dsee Fig. 4.14 for lo-dependence Visual: c ¼ 3.1 [25]; c ¼ 2.15e2.78 [26]; c ¼ 1.53e2.42 [27]; 2.3e2.9 [29] CMOR: c ¼ 1.82e2.36 (s ¼ 1.65e1.93) [22]; MAARSY: c ¼ 2.59 (1.95) [23] Lightcurve: Ib: Hb ¼ 112.9  1.09 Mv; Hmax ¼ 103.8 þ 0.90 Mv; He ¼ 98.1 þ 1.46 Mv (N ¼ 113,800) III: Hb ¼ 100.2  0.30 Mv; Hmax ¼ 94.9 þ 0.70 Mv; He ¼ 90.3 þ 0.77 Mv (N ¼ 11,886) Meteoroid density: r ¼ 0.25  0.05 g/cm3, progressive fragmentation index 0.46  0.60 [13] r ¼ 0.5  0.2 g/cm3, porosity K ¼ 79% [20]; 0.9  0.5 g/cm3, 62% [21] Ib: r w 0.45  0.04 g/cm3 (a1 ¼ 0.050 km, a2 ¼ 7.62/s) III: r w 1.61  0.25 g/cm3 (a1 ¼ 0.041 km, a2 ¼ 14.05/s) dpossibly Na free or irons Strength: PE: 15% II, 55% IIIA, 30% IIIB [29]; rairV2 ¼ 0.022 (0.007e0.065) MPa [28] Spectroscopy: Ib: Mg0.73 Fe0.75 Na0.017 (N ¼ 15), Na somewhat depleted, strong O Age: 9000e14,000 y, Halley first in inner solar system about 18,000 y ago [10] ZHR early rise: 5000e2600 y, but rest of peak older 5000e10,000 [22] From c: w17,000 y, from s (core): w25,000 y Source: 1P/Halley Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Epoch 1994-Feb-17.0 TDB 17.8 0.586 0.967 162.3 111.3 58.4 169.7 Dynamic type: Shower type: Years of outbursts:

Brief history: Discovered during stereoscopic observations by [1] from Clausberg and Sesebühl in Germany, respectively, on October 14/15, 1798. In a letter written 1838 December 24, [2] noted that October 8e15 was a season when “meteors may possible be found unusually numerous.” In 1839, [3] from 1805 to 1838 observations also singled out October. [4] determined radiant visually from 11 meteors at R.A. ¼ 90 , Decl. ¼ þ16 on October 18, 1864. [5] measured radiant drift. First photographic radiant in single-station observations by [6] during October 20, 1922. Triangulated meteors by [16], showing no evidence for multiple Orionid radiants as reported by visual observers. First radar detection from 61 meteors by [14] (shower 49). [7] determined radiant drift in CMOR radar data at þ0.78 and þ0.02/ . Link with comet 1P/Halley long suspected, but remained uncertain due to a large Earth-comet miss-distance (0.155 AU for Orionids and 0.066 AU for eta-Aquariids). Comet orbit integrated back to 1404 BCE by [8], grounded in observations. From this, [9,15] developed the “shell model” of Orionids and etaAquariids meteoroid streams, showing that secular evolution is forced by mean-motion resonance, so that U and u oscillate over a narrow range of values. On top of annual activity (Fig. 4.14) occasional outbursts are seen that are more rich in bright meteors [10]. [19] associated 2006 outburst with 1:6 resonant dust ejected in 1265, 1197, and 910 BCE. [29] placed it in 1:5 resonance. Name by [11], number by [12]. Forms complex with #337.

References: [1] Benzenberg J. F., Brandes H. W. (1800) Versuche die Entfernung, die Geschwindigkeit und die Bahnen der Sternschnuppen zu bestimmen. Hamburg: Friedrich-Perthes, pp. 41e60; [2] Herrick E. C. (1839) The American J. of Sci. and Arts 35, 361e368; [3] Quetelet L. A. J. (1839) Nouveaux Mém. de l’Académie Roy. des Sci. et Belles-Lettres de Bruxelles 12, 56 pp. (p. 25); [4] Herschel A. S. (1865) MNRAS 26, 53e75; [5] Olivier C. P. (1923) The Observatory 46, 17e18; [6] Olivier C. P. (1923) The Observatory 46,

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89

October

188e189; [7] Brown P. G., et al. (2010) Icarus 207, 66e81; [8] Yeomans D. K., Kiang T. (1981) MNRAS 197, 633e646; [9] McIntosh B. A., Hajduk A. (1983) MNRAS 205, 931e943; [10] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 493e494. [11] Denning W. F. (1877) The Observatory 1, 243e244; [12] Jacchia L. G., et al. (1961) SCoA 4, 97e129; [13] Verniani F. (1967) SCoA 10, 181e195; [14] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 11, 183e199; [15] McIntosh B. A., Jones J. (1988) MNRAS 235, 673e693; [16] Wright F. W., Whipple F. L. (1948) AJ 54, 54e54; [17] Miskotte K. (1993) JIMO 6, 292e292; [18] Rendtel J. (2008) EMP 102, 103e110; [19] Sato M., Watanabe J.-I. (2007) PASJ 59, L21eL24; [20] Narziev M. (2019) PSS 173, 42e48; [21] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [22] Egal A., et al. (2020) AA 642, A120eA147; [23] Schult C., et al. (2018) Icarus 309, 177e186; [24] Egal A., et al. (2020) AA 640, A58eA81; [25] Jenniskens P. (1994) AA 287, 990e1013; [26] Dubietis A. (2003) JIMO 31, 43e48; [27] Rendtel J. (2008) EMP 102, 103e110; [28] Shrbeny L., Spurny P. (2019) AA 629, A137eA146; [29] Spurny P., Shrbeny L. (2008) EMP 102, 141e150; [30] Arlt R., et al. (2008) JIMO 36, 55e60; [31] Ogawa H., Steyaert C. (2017) JIMO 45, 98e106.

Nov. (lo ¼ 222 )

Narrow Apex Source

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Age: Meteoroid density: Source: Orbital elements (J2000.0) Epoch 1994-Feb-17.0 TDB

Evolved Halley-type comet dust? Annual shower All year (lo ¼ 0 e360 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 221.7 171.6 þ22.5 270.1 þ15.7 53.9 þ1.04 0.02 0.00 0.01 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.85 0.696 0.185 146.1 359.0 221.7 225.6 0.220 0.190 21.2 23.8 77.0 78.4 þ0.0001 0.0002 þ0.02 0.02 þ1.00 þ0.97 N ¼ 13,751 *) for northern apex component only e w105 y [3] r ¼ 0.4e3.5 g/cm3 1P/Halley a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.8 0.586 0.967 162.3 111.3 58.4 169.7

[see plate in Fig. 4.15]

eR[MU]*

Brief history: Low-e orbits center on u ¼ 0 or 180 within 40 range, form a narrow band at the center of the apex source in MU Radar observations. First described by [1] from Jicamarca high-power large-aperture VHF radar observations, the component was described by [2] from MU-Radar head-echo observations as the “Narrow Apex Source.” Weaker in AMOR data. Only weakly detected in SAAMER and CMOR radar observations, with a concentration to higher ecliptic latitudes. Not detected in low-light video observations. Component explained from dynamical model of the sporadic meteoroid complex by [3] as evolved small 100 micron old 105 y dynamically evolved meteoroids FIG 4.14 Orionid ZHR (•) and c (o) profile. originating from 55P/Tempel-Tuttle or an object in a similar orbit. Given the predominance of 1P/Halley dust in the apex source region over extended range of solar longitude, it is concluded here that this component is likely evolved dust from 1P/Halley (Fig. 4.15). References: [1] Chau J. L., Woodman R. F., Galindo F. (2007) Icarus 188, 162e174; [2] Kero J., Szasc C., Nakamura T., Meisel D. D., Ueda M., Fujiwara Y., Terasawa T., Nishimura K., Watanabe J. (2012) MNRAS 425, 135e146; [3] Wiegert P., Vaubaillon J., Campbell-Brown M. (2009) Icarus 201, 295e310.

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91

November

Nov. 4 (lo ¼ 222 )

388 CTA d chi Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak activity: Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, sunskirter, TJ ¼ þ1.10  0.46 Annual shower September 29eNovember 30 (lo ¼ 186 e248 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 222.0 63.7 þ25.8 204.8 þ4.8 42.6 þ0.95 þ0.10 þ0.14 0.05 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.65 0.090 0.989 16.6 325.8 221.9 187.7 eV 0.0338 0.0143 6.58 11.9 16.06 11.9 þ0.0015 0.0001 0.36 0.31 þ1.00 þ0.69 4.97 0.081 0.984 12.3 328.5 220.0 188.5 e R[1] Possible narrow secondary maximum around lo ¼ 242 (Fig. 4.16). w0.4 (N ¼ 2180, hr ¼ 60.5 , m(Mv ¼ 0) ¼ 0.06 g) 3.05  0.08 (s ¼ 2.21  0.03) Component IIb has low He, ke < 79, like III; High III/II ratio: IIa: Hb ¼ 103.9  0.88 Mv; Hmax ¼ 93.4 þ 0.90 Mv; He ¼ 86.5 þ 1.67 Mv (N ¼ 633) IIb: Hb ¼ 97.9  0.35 Mv; Hmax ¼ 90.0 þ 0.91 Mv; He ¼ 84.6 þ 1.24 Mv (N ¼ 387) III: Hb ¼ 92.5 þ 0.05 Mv; Hmax ¼ 87.8 þ 0.83 Mv; He ¼ 83.6 þ 0.89 Mv (N ¼ 816) IIa: r w 0.81 g/cm3 (a1 ¼ 0.109 km, a2 ¼ 4.91/s) IIb: r w 1.4 g/cm3 (a1 ¼ 0.078 km, a2 ¼ 7.09/s) dpossibly Na poor dpossibly Na free III: r w 2.0  0.7 g/cm3 (a1 ¼ 0.0565 km, a2 ¼ 10.98/s) From c: w4500 y, from s: w11,000 y C/1953 X1 (Pajdusáková) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.072 (1.00) 13.6 94.1 115.3 209.4

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 1953-Dec-12.0 UT

FIG 4.15

MU-Radar detection of Narrow Apex Source.

FIG 4.16

ZHR profile CTA (#388).

Brief history: First recognized in CMOR radar data by [1] from R.A. ¼ 63.2 , Decl. þ24.7 and Vg ¼ 42.1 km/s around lo ¼ 220.0 . Confirmed from video triangulations by [2]. Low q and low i cause rapid rotation of nodal line. Possible source C/1953 X1 identified here. Activity curve shown in Fig. 4.16 has secondary peak at lo when P is that of C/1953 X1. Name and number by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81; [2] Jenniskens P., et al. (2016) Icarus 266, 331e354.

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November

93

Nov. 18 (lo ¼ 236 )

13 LEO d Leonids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet shower, from Halley-type comet, TJ ¼ 0.46  0.57 Annual shower with episodic outbursts Numerous since 902 CE (see Table 4.1) October 26eDecember 26 (lo ¼ 213 e274 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 236.3 154.4 þ21.4 272.1 þ10.1 70.3 þ0.63 0.38 0.29 0.13 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.81 0.984 0.874 162.5 173.4 236.3 49.7 eV 0.0059 0.205 2.03 4.27 6.82 4.27 1 þ0.0013y 0.0004 þ0.23 þ1.06 þ1.00 þ2.06 ) 1 N ¼ 13,815 (hr ¼ 51.2 , m(Mv ¼ 0) ¼ 0.02 g) ) lo < 237 ZHR ¼ 13/h in normal years [25,29]; 23  6, B ¼ 0.39  0.08/ [24] c ¼ 2.39  0.02 (s ¼ 1.95  0.01); c ¼ 2.5 [25]; c ¼ 3.4 [24] Component IIb has low He, Ke < 79, like III: I: Hb ¼ 115.8  1.36 Mv; Hmax ¼ 106.5 þ 1.16 Mv; He ¼ 99.3 þ 1.64 Mv (N ¼ 6248) IIb: Hb ¼ 102.2  0.30 Mv; Hmax ¼ 97.2 þ 0.08 Mv; He ¼ 92.4 þ 0.25 Mv (N ¼ 162) I: low F ¼ 0.56, fragile meteoroids (also: early release of Na during storms) r ¼ 1.2  0.2 g/cm3, porosity K ¼ 45% [20]; 0.6  0.2 g/cm3, 74% [22] I: r  0.35  0.06 g/cm3 (a1 ¼ 0.083 km, a2 ¼ 5.55/s), lower if fragile IIb: r w 1.74  0.47 g/cm3 (a1 ¼ 0.031 km, a2 ¼ 16.47/s) dlikely Na poor PE-coefficient 5 to 14 magn. fireballs: 58% IIIB (weak), 34% IIIA, 8% II [26] Not surviving dynamic pressure rairV2 ¼ 0.016 (0.002e0.05) MPa [26] Mg1.08 Fe0.82 Na0.049 (N ¼ 8), chond.; depleted Fe, C [20,21]; H present [27] Dust-trail encounters: 1200 y; annual: From c and s: w25,000 y 55P/Tempel-Tuttle a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 10.3 0.976 0.906 162.5 172.5 235.3 47.8

Lightcurve shape: Meteoroid density:

Meteoroid strength: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1998-Aug-15.0 TDB

Brief history: The early morning November 13, 1833, storm observed in eastern North America started the field of meteor astronomy by establishing the shower “radiant.” Olmsted placed it at R.A. ¼ 150 ,  Decl. ¼ þ20 in Leo [1], while A. C. Twining then, in a letter to Olmsted [2], refined that to R.A. ¼ 148.4 , Decl. ¼ þ22.7 (Eq. J2000.0) [28]. It was recalled that 33 years earlier, [3] had reported a storm over Cumaná, Venezuela in 1799, and had learned of a similar event “about 30 years earlier”ddated later to November 9, 1771 [4]. Historic storm accounts identified by [5] showed the peak date had changed from October 12, in 902 CE, to November 13 in 1833. Much lower annual activity recognized in following years FIG 4.17 ZHR profile annual. (Activity curve in Fig. 4.17). Expectations for level of 1866 activity were satisfied with a meteor storm. From radiant and peak time, parabolic orbital elements were calculated by [6,7] and the shower was associated with 1865 comet 55P by [8e10]. Returns in 1899 and 1932 were disappointing. The storm of 1966 came unexpected [4]. Leading up to the 1998 return, concerns were raised about the impact hazard to satellites [11]. [12] integrated the orbit of 55P back in time and mapped the dust density relative to comet from past accounts. [13] added the changing dust trail positions due to Sun’s reflex motion to show dust trails would be near Earth orbit in 2001e2002.

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TABLE 4.1

Partial list of outbursts from 55P/Tempel-Tuttle dust trail encounters. Time (UTC)

Eject

lo ( )

Dr (AU)

Dao (AU)

fm (AU)

902-10-12 934-10-13 967-10-14 1002-10-14 1037-10-14 1101-10-16 1771-11-09 1799-11-12 1832-11-13 1833-11-13 1868-11-14 1869-11-13 1903-11-16 1965-11-17 1966-11-17 1969-11-17 1998-11-17 1999-11-18 1999-11-18 2000-11-17 2000-11-18 2000-11-18 2001-11-18 2001-11-18 2001-11-18 2002-11-19 2002-11-19 2003-11-13 2006-11-19

20:54 21:54 09:16 12:06 13:27 23:20 06:18 06:20 00:45 09:02 05:23 23:23 04:53 19:40 10:58 08:57 19:45 02:10 20:05 08:00 08:05 03:50 18:31 09:59 18:02 10:51 04:06 01:13 04:46

802 802 901 935 935 935 1600 1600 1699þ 1800þ 1833 1767 1533 1733 1932 1932 1899 1899 1866 1932 1866 1733 1866 1767 1699 1866 1767 1499 1932

219.247 220.086 220.098 220.244 220.328 222.336 229.881 232.725 233.030 233.126 234.004 233.494 234.007 235.740 235.119 235.271 235.281 235.292 236.045 235.273 236.286 236.107 236.471 236.113 236.451 236.898 236.614 230.905 236.615

þ0.00099 þ0.00003 þ0.00007 þ0.00085 þ0.00091 0.00031 0.00027 þ0.00005 0.0006 þ0.00086 0.00047 þ0.00082 þ0.00033 0.00085 0.00026 þ0.00062 0.00428 þ0.00122 0.00135 þ0.00242 0.00036 0.00063 þ0.00020 þ0.00069 0.00006 þ0.00069 þ0.00054 þ0.00310 þ0.00010

þ0.0478 0.0049 0.0509 þ0.1418 þ0.2235 0.0507 þ0.2309 0.0051 0.0001 þ0.169 þ0.5617 þ0.3131 þ0.0749 þ0.0279 þ0.5531 þ1.6998 þ0.0572 þ0.1355 þ0.0829 þ0.3163 þ0.1121 þ0.0635 þ0.1392 þ0.0789 þ0.0426 þ0.1688 þ0.1113 þ0.2467 þ0.963

0.323 0.074 0.720 0.615 0.408 0.254 0.653 0.122 11.06 1.075 0.439 0.609 0.275 0.110 3.369 1.407 0.008 0.448 0.203 1.790 0.158 0.334 0.155 0.185 0.269 0.168 0.163 0.926 0.620

[4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4]

R.A. ( )

Decl. ( )

Vg (km/s)

lo ( )

W ( )

c

ZHR (/h)

e e e e e e e e e 151.8 e e e 154.3 153.2 153.8 e 153.6 154.1 153.6 154.2 153.7 154.5 154.1 154.6 154.2 154.3 e 154.7

e e e e e e e e e þ22.3 e e e þ22.7 þ21.8 þ22.3 e þ21.7 þ21.5 þ21.7 þ21.4 þ21.6 þ21.3 þ21.6 þ21.4 þ21.5 þ21.5 e þ21.0

e e e e e e e e e 70.8 e e e 71.0 71.0 70.9 e 70.7 70.7 70.7 70.7 70.6 70.8 70.7 70.9 71.5 70.9 e 70.6

219.4 219.9 220.4 220.5 220.5 222.6 229.9? 232.82 233.15 233.144 234.010 233.536 234.029 235.65 235.166 235.274 235.300 235.282 235.910 235.276 236.276 236.090 236.451 236.140 236.433 236.898 236.616 230.9 236.610

e e e e e e e w0.05 e e e e w0.132 0.08 0.028 0.027 0.130 0.031 0.12 0.070 0.070 0.080 0.040 0.055 0.090 0.024 0.022 e 0.030

e e e e e e e

e e e e e e Storm Storm Storm w6000 w110 w1000 w500 300 15,000 400 65 4200 50 350 250 170 1400 600 680 3400 2000 20 80

e e e e e e 2.99 2.96 1.91 2.38 1.96 >2.0 2.21 2.11 2.29 1.80 1.80 3.05 2.58 e 2.60

[4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [4] [23]

November

Date

From: Vaubaillon in [4], page 619e635.

95

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November

97

Airborne and ground-based observing campaigns mobilized new technologies [14]. First dust trail model by [15], further developed by [16,17]. The year 1999 observations proved predicted time of encounter correct. Other dust trail encounters are listed in Table 4.1. [31] pointed out that underlying broad activity is a broader “Filament” component responsible for 1998 fireballs. Unresolved differences between models and observations are discussed by [4,23]. Annual stream from CAMS FIG 4.18 The Leonid meteoroid stream from CAMS data. video observations in Fig. 4.18. Predictions to 2100 CE by [30]. Name goes back to early 19th century accounts, e.g., [18], number by [19]. References: [1] Olmsted D. (1833) Independence (November 20 issue), New York, p. 2; [2] Olmsted D. (1834) Amer. J. Science and Arts 25, 363e411; [3] von Humboldt A. (1818) Personal Narrative of Travels to the Equinoctial Region of the New Continent, Vol. 3. London: Longman, Hurst, Rees, Orne, and Brown, pp. 331e333; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, Ch. 15; [5] Newton H. A. (1863) Amer. J. Sci. Arts Ser. 2, 36, 143e149; [6] Schiaparelli G. V. (1866) Bullettino Meteorologico dell’Osservatorio del Collegio Romano 5, 127e133; [7] Le Verrier U. J. J. (1867) Rendus Hebdomadaire des Séances de l’Acedémie des Sci. 64, 94e99; [8] Peters C. F. W. (1867) AN 68, 287e288; [9] Schiaparelli G. V. (1867) AN 68, 331e332; [10] Oppolzer T. (1867) AN 68, 333e334; [11] Ailor W. (1998) Testimony to the U.S. House of Repr., Committee on Science, Subcommittee on Space and Aeronautics. May 21; [12] Yeomans D. K. (1981) Icarus 47, 492e499; [13] Jenniskens P., Butow S. J. (1998) Proc. Leonid Threat and Impact Hazard Workshop. Manhattan Beach, CA., Ed: D. Lynch, El Segundo: The Aerospace Corporation; [14] Jenniskens P., Butow S. J., Fonda M. (2000) EMP 82e83; 1e26; [15] Kondratéva E. D., Reznikov E.A. (1985) Solar System Research 19, 96e101; [16] McNaught R. H., Asher D. J. (1999) JIMO 27, 85e102; [17] Lyytinen E., van Flandern T. (1999) Meta Research Bull. 8, 33e40; [17] Jacchia L. G., Verniani F., Briggs R. E. (1967) SCoA 10, 1e139; [18] Denning W. F. (1895) Nature 53, 7e9; [19] Jacchia L. G., Whipple W. F. (1961) SCoA 4, 97e129; [20] Narziev M. (2019) PSS 173, 42e48; [20] Borovicka J., et al. (2010) MAPS 34, 987e994; [21] Kasuga T., et al. (2005) AA 435, 341e351; [22] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [23] Jenniskens P., et al. (2008) Icarus 196, 171e183; [24] Jenniskens P. (1994) AA 287, 990e1013; [25] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [26] Shrbeny L., Spurny P. (2009) AA 506, 1445e1454; [27] Jenniskens P., Mandell A. M. (2004) Astrobiology 4, 123e134; [28] Kronk G. W. (2014) Meteor Showers. An Annotated Catalog. New York: Springer, p. 269; [29] Molau S., et al. (2018) JIMO 46, 142e146; [30] Maslov M. (2007) JIMO 35, 5e12; [31] Jenniskens P. (2003) JIMO 31, 135e136.

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December

99

Dec. 9 (lo ¼ 257 )

16 HYD d sigma hydrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.09  0.50 Annual shower November 22eJanuary 18 (lo ¼ 240 e298 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 256.6 125.6 þ2.4 230.9 16.5 58.9 þ0.85 0.29 0.06 0.05 0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 18.0 0.257 0.986 128.8 119.3 76.6 196.2 eV 0.0437 0.0596 3.72 7.15 8.30 7.15 0.0005 0.0002 0.22 þ0.08 þ1.00 þ1.08 December 4 (lo ¼ 252.4 ) N ¼ 15,659 (hr ¼ 49.5 , m(Mv ¼ 0) ¼ 0.03 g) ZHR ¼ 2.5  0.5/h, B ¼ 0.10  0.03/ [7]; ZHR ¼ 7/h [8] c ¼ 2.74  0.06 (s ¼ 2.09  0.02); c ¼ 3.0 [6]; 2.6 [9] Component Ib has low He, Ke < 82: Ib: Hb ¼ 110.2  1.20 Mv; Hmax ¼ 98.4 þ 1.67 Mv; He ¼ 93.0 þ 2.20 Mv (N ¼ 7579) III: Hb ¼ 99.2  0.48 Mv; Hmax ¼ 92.9 þ 1.01 Mv; He ¼ 87.9 þ 1.42 Mv (N ¼ 184) Ib: r w 0.61  0.09 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 6.09/s) dchondritic Na dpossibly Na poor/free III: r w 1.5  0.7 g/cm3 (a1 ¼ 0.0815 km, a2 ¼ 6.94/s) Ib: Mg0.79 Fe0.66 Na0.041 (N ¼ 14), chondritic, strong O emission From c: w15,000 y, s suggests older w30,000 y; From model: w56,000 y C/2023 P1 (Nishimura) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 65 0.225 0.996 132.5 116.3 66.8 183.1

Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2023-Aug-20.0 TDB

Brief history: First detected from seven 1952e1954 Harvard Super-Schmidt photographed orbits by [1]. Three precisely reduced orbits by [2] had a radiant at R.A. 126.7 , Decl. ¼ þ1.8 . Shower detected visually in 1963 and 1964 by [3]. Looking back, [4] identified observations of shower from Namibia by C. Hoffmeister in 1937. Confirmed from intensified video observations over Japan by [5] with R.A. ¼ 130.4 , Decl. ¼ þ1.5 and Vg ¼ 57.7 km/s. Detected in low-light video observations by [10], who noticed a late diffuse component. Significant range of perihelion distance (q) and inclination and strong correlation with P. We notice here that lower q orbits have slightly lower beginning heights on average. Activity curve shown in Fig. 4.19. FIG 4.19 ZHR profile annual. Early model by [6] shows a fairly stable orbit, finding that date of maximum did not change from that of present back in 950 CE, with radiant at R.A. ¼ 125.8 , Decl. ¼ þ1.1 . In 2950 CE, maximum will occur about 1 day later than at present with radiant at R.A. ¼ 127.0 , Decl. ¼ þ1.6 [6]. [11] classified one s-Hydrid with high Kc ¼ 117 km as Na poor. Association with C/2023 P1 by [12]. Name and number by [2]. References: [1] McCrosky R. E., Posen A. (1961) SCoA 4, 15e84; [2] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [3] Srirama Rao M., et al. (1969) AuJP 22, 767e772; [4] Kronk G. W. (2014) Meteor Showers, an Annotated Catalog. 2nd ed., New York: Springer, p. 324; [5] Shigeno Y., Yamamoto M.-Y. (2012) JIMO 40, 24e35; [6] Fox K. (1986) In: Asteroids, Comets, Meteors II. Eds: H. Rickman, C.-I. Lagerkvist, Uppsala: Univ. of Uppsala, pp. 521e525; [7] Jenniskens P. (1994) AA 287, 990e1013; [8] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [9] Shiba Y., Ueda M. (2013) JIMO 41, 7e10; [10] Jenniskens P., et al. (2016) Icarus 266, 331e354; [11] Matlovic P., et al. (2019) AA 629, A71eA90; [12] Ye Q.-Z., Greaves J. (2023) CBET 5290, CBAT, D.W.E. Green (ed.), 1pp.

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101

Dec. 13 (lo ¼ 262 ) 4 GEM d Geminids Asteroid, Phaethon Complex, TJ ¼ þ4.41  0.32 Annual shower November 7eDecember 24 (lo ¼ 225 e273 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 261.6 113.0 þ32.4 208.1 þ10.5 33.8 þ1.04 0.16 0.09 0.03 þ0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.31 0.145 0.889 22.9 324.3 261.6 225.8 eV 0.0239 0.0279 4.26 3.13 2.78 3.13 þ0.0001 þ0.0008 0.04 0.10 þ1.00 þ0.90 N ¼ 104,490 (hr ¼ 60.1 , m(Mv ¼ 0) ¼ 0.11 g) 1980e1990: ZHR ¼ 88  4/h [26]; core: ZHR ¼ 74  4/h, Bþ ¼ 0.59, B ¼ 0.81; bkg: ZHR ¼ 18  2/h, Bþ ¼ 0.09  0.03, B ¼ 0.31  0.12/ [26] 1990e1999: ZHR ¼ 115/h, 2001e2009: ZHR ¼ 105/h [36] 2020e2021: ZHR ¼ 125/h [13]; ZHR ¼ 128.2  3.3 [39]; rising [27] 2002e2022: steady for faint CMOR-radar detected meteors [30] Incoming mass: 75  25 kg/activity period [31] Magn. distribution index: lo-dependence in Fig. 4.20; visual data suggest 0.6 lower values [e.g., 37] Max lo ¼ 262.0 : c ¼ 2.67  0.05 (s ¼ 2.07  0.02) Max lo ¼ 262.0 : c ¼ 2.00  0.03 [28]; c ¼ 2.30  0.05 [29] Lightcurve: Component II has low He, KE < 79, like III: IIa: Hb ¼ 98.3  0.55 Mv; Hmax ¼ 88.8 þ 1.71 Mv; He ¼ 83.3 þ 2.38 Mv (N ¼ 31,416) II: Hb ¼ 97.8  0.86 Mv; Hmax ¼ 83.1 þ 2.38 Mv; He ¼ 78.3 þ 3.11 Mv (N ¼ 13,922) IV: Hb ¼ 79.8 þ 0.03 Mv; Hmax ¼ 72.1 þ 0.69 Mv; He ¼ 63.6 þ 1.07 Mv (N ¼ 95) Meteoroid density: r ¼ 3.6  0.3 g/cm3, porosity K ¼ 0% [14]; 2.9  0.6 g/cm3, 0% [18]; 1g: compact, 3.0 g/cm3 [34]; Bright fireballs: r ¼ 0.7e1.3 g/cm3 [24] IIa + II: r w 1.30  0.05 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 6.01/s) dNa poor IV: r w 3.1  0.7 g/cm3 (a1 ¼ 0.113 km, a2 ¼ 5.58/s) dpossibly Na free or irons Strength: Max. dynamic pressure rairV2 ¼ 0.19 MPa (0.01e1 MPa) [32]; ablation coefficient 0.006e0.0028 s2/km2, at low end of Ceplecha group I [35] Spectroscopy: Mg1.08 Fe0.75 Na0.015 (N ¼ 82); Line ratios (component II): Na/Mg ¼ 0.0036  0.0005, lower than chondritic, Ni/Mg ¼ 0.078  0.0012, higher [25]; Some grains devoid of Na [15]; H present [32,33]; smaller pore size correlates with higher Na abundance [34] Age: w989 y [13]; 800e1000 y [19] Source: 3200 Phaethon Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Epoch 2022-Jan-21.0 TDB 1.27 0.140 0.890 22.3 322.2 265.2 227.4

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR:

Brief history: Possible Geminids observed in low numbers in the 1830s to 1850s [1]. First visually determined radiant by [2] on December 10/11, 1862, placing it around Castor and Pollux in Gemini. “Meteors were not remarkable for number or brilliancy.” [3] placed radiant from 17 plotted meteors at R.A. ¼ 105.5 , Decl. ¼ þ30.5 on December 12/13, 1863. Shower remained poorly observed, in part due to winter weather, but rates gradually increased. More visual observations reported in the 1880s [e.g., 20]. [4] suspected daily motion of radiant as early as 1885 and gave ephemeris in 1923. Jodrell Bank Experimental Station detected Geminids by radar starting in 1946 [5], with radiant movement measured in 1949 and 1950. [6] measured first photographed orbits and noticed unusually short, eccentric, and inclined orbit. Using that orbit, [7] calculated secular perturbations and found shift in node by 0.017 per year. Node shifted from inside to outside Earth orbit, explaining increase in rates and predicting future decline. First radar radiant by [21] from R.A. ¼ 113.4 , Decl. ¼ þ31.4 at lo ¼ 260.8 (B1950.0) during 1952e1957. First Geminid spectrum on December 14, 1954 [22]. Radar observations with MAARSY by [23]. First age estimate (w4700 y) by [8] based on change of orbital parameters with meteor magnitude. [9] determined from visual observations of B.A.A. Meteor Section how mean magnitude of meteors changes with solar longitude, noting that “in the two days before maximum there is a moderate concentration of small

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4 GEMdGeminids

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103

FIG 4.20 Left: ZHR profile (•). Right: c profile, measured from the 2 to þ4 magnitude range (•) and from 5 to 2 magnitude range (þ) of the observed distribution, compared to profile (o) from visual data [29].

particles,” while just after maximum, “the Earth then moves into a region of larger particles”. [13] found two components in Geminid stream, a narrow peak of bright meteors and a broader background of fainter meteors. [37] shows how stream profile, full-width-at-halfmaximum, and peak rate change with magnitude (Fig. 4.20). [10] noticed shift in the time of maximum of 0.008 per year. [35] noticed semi-major axis is shorter for larger meteoroid masses. Parent body discovered in 1983 and linked to Geminids by [11]. [16,17] showed that q of stream is low enough to melt alkaline silicates in meteoroids. However, [38] found no correlation between sodium content and present day perihelion distance. Name dates from late 19th century, number by [12]. References: [1] Kronk G. W. (2014) Meteor Showers, an Annotated Catalog, 2nd ed. New York: Springer, p. 313e324; [2] Marsh B. V. (1863) American J. of Science and Arts (Ser. 2) 35, 302e302; [3] Hershel A. S. (1864) MNRAS 25, 162e163; [4] Denning W. F. (1923) MNRAS 84, 43e56; [5] Hawkins G. S., Almond M. (1952) MNRAS 112, 219e233; [6] Whipple F. L. (1947) Proc. of the Am. Philosophical Soc. 91, 189e200; [7] Plavec M. (1950) Nature 165, 362e363; [8] Jones J. (1978) MNRAS 183, 539e546; [9] Spalding G. H. (1982) J. BAA 92, 227e233; [10] Rendtel J. (2004) JIMO 32, 57e59; [11] Whipple F. L. (1983) IAU Circular 3881, Cambridge, MA: IAU Minor Planet Center, Ed. B. G. Marsden, 1pp; [12] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [13] Jenniskens P. (2006) Meteor Showers and their Parent Comets. CUP, Chapt. 22; [14] Narziev M. (2019) PSS 173, 42e48; [15] Borovicka J., et al. (2005) Icarus 174, 15e30; [16] Kasuga T., et al. (2005) AA 435, 341e351; [17] Kasuga T., et al. (2006) AA 453, L17eL20; [18] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [19] Jakubík M., Neslusan L. (2015) MNRAS 453, 1186e1200; [20] Sawyer E. F. (1880) Observatory 3, 347e348; [21] Weiss A. A. (1959) Austral. J. Phys. 12, 315e319; [22] Millman P. M. (1955) J. Royal Astron. Soc. Canada 49, 169e172; [23] Stober G., Schult C., Baumann C., Latteck R., Rapp M. (2013) Ann. Geophys. 31, 473e487; [24] Halliday I. (1988) Icarus 76, 279e294; [25] Kasuga T., Watanabe J.-I., Ebizuka N. (2005) AA 438, L17eL20; [26] Jenniskens P. (1994) AA 287, 990e1013; [27] Ryabova G. O., Rendtel J. (2018) MNRAS 475, L77eL80; [28] Arlt R., Rendtel J. (2006) MNRAS 367, 1721e1726; [29] Jenniskens P. (1988) DMS Visueel Handboek. Leiden: DMS, p. 140e145; [30] Campbell-Brown M. (2022) Presentation at Meteoroids 2022 (virtual, Huntsville); [31] TrigoRodríguez J. M., Blum J. (2022) MNRAS 512, 2277e2289; [32] Shrbeny L., Spurny P. (2019) AA 629, A137eA146; [33] Jenniskens P., Mandell A. M. (2004) Astrobiology 4, 123e134; [34] Borovicka J., et al. (2009) In: Proc. IAU Symp. 263, Ed.: Fernandez J. A., et al., Cambridge: IAU/CUP, p. 218e222; [35] Spurny P. (1993) In: Meteoroids and their Parent Bodies. Bratislava: Astron. Inst. Slovak Acad. Sci., p. 193e196; [36] Miskotte K., et al. (2011) JIMO 39, 167e186; [37] Uchiyama S. (2010) JIMO 38, 31e35; [38] Sekiguchi T. (2020) eMeteorNews 5, 192e195; [39] Vida D., et al. (2022) MNRAS 515, 2322e2339.

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105

Dec. 22 (lo ¼ 270 )

15 URS d Ursids

Dynamic type: Shower type: Years of outbursts:

Mellish-type shower, from Jupiter-family comet, TJ ¼ þ1.74  0.14 Annual shower with episodic outbursts Aphelion: 1945, 1986, 2000, 2014; Perihelion: many, almost yearly 1945: lo > 271.324 , ZHR > 120/h, W ¼ 0.05 , c ¼ e [11] e1392 trail e1378 trail 1986: lo ¼ 270.935 , ZHR ¼ 110/h, W ¼ 0.05 , c ¼ 2.8 [11] 2000: lo ¼ 270.780 , ZHR ¼ 90/h, W ¼ 0.09 , c ¼ 3.2 [11] e1405 trail 2014: lo ¼ 271.85 , ZHR ¼ 45  19/h, c ¼ 1.8  0.6 [21,22] e1392 trail December 7eJanuary 6 (lo ¼ 255 e286 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 270.5 218.5 þ75.9 216.8 þ71.6 32.7 þ2.43 0.40 þ0.48 þ0.25 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.02 0.938 0.820 52.2 206.4 270.5 116.6 eV 1 0.0106 0.0782 1.84 1.51 0.21 1.51 ) þ0.0017 þ0.0000 þ0.12 0.48 þ1.00 þ0.52 1 N ¼ 4531 (hr ¼ 37.5 , m(Mv ¼ 0) ¼ 0.12 g) ) core Annual: ZHR ¼ 11.8  2.5/h, B ¼ 0.61  0.12/ [16]; 4.5/h [18]; 16  2/h [19] Annual: c ¼ 2.75  0.07 (s ¼ 2.10  0.03); c ¼ 3.4 [16]; 2.8 [17] Component IIb has low He, Ke < 79, like III: I: Hb ¼ 104.0  0.83 Mv; Hmax ¼ 93.5 þ 1.69 Mv; He ¼ 88.6 þ 2.16 Mv (N ¼ 1627) IIb: Hb ¼ 92.3  0.58 Mv; Hmax ¼ 84.6 þ 0.83 Mv; He ¼ 79.0 þ 1.18 Mv (N ¼ 214) I: r w 0.98  0.15 g/cm3 (a1 ¼ 0.1055 km, a2 ¼ 3.26/s) IIb: r w 1.7  0.3 g/cm3 (a1 ¼ 0.196 km, a2 ¼ 3.06/s) dpossibly Na free I: Mg1.23 Fe0.63 Na0.071 (N ¼ 3), Fe depleted Filament: >1000e13,000 y; Aphelion outbursts: w600 y [12] Annual: From c and s: w24,000 y; Earth through core of stream (sU < su) 8P/Tuttle captured w 15,000 y ago when node was last near Jupiter [15] 8P/Tuttle a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.70 1.027 0.820 55.0 207.5 270.3 117.8

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density: Spectroscopy: Age:

Source: Orbital elements (J2000.0) Epoch 2008-Jul-18.0 TDB

Brief history: Theoretical radiant by [1], but large miss distance. In response, [2] noted activity from R.A. ¼ 220 ,  Decl. ¼ þ76 during December 18e25 in rare clear nights in 1876 and 1885, “but the display has shown no special abundance.” Shower was forgotten until evening December 22, 1945, when four observers at Skalnaté Pleso Observatory during 16:30e20:45 UT [3] had peak ZHR ¼ 108 at 18:15e18:25 UT [4]. Photographic radiant of “Umids” at R.A. ¼ 217.1 , Decl. ¼ þ75.9 [4]. Link with 8P by [3], but uncertain: comet was at aphelion. Annual activity by Jodrell Bank radar from R.A. ¼ 195  8 , Decl. ¼ þ78  5 in 1947 [5]. ZHR ¼ 3e10/ h in later years. Another aphelion outburst seen from Norway and from England on December 22, 1986 [6,7]. These explained FIG 4.21 ZHR profile, scaled to [16]. by [11] as dust trapped in 7:6 meanmotion resonance with Jupiter, just outside the resonance that traps the comet (15:13), so that dust moves away from the comet and lags half an orbit 45 revolutions later, the time it takes for the trail to evolve into Earth’s orbit. The year 2000 CE outburst predicted by [12] and observed by [13]. With comet near perihelion, “Filament” outbursts were observed in 1982 (lo ¼ 270.995 )

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15 URSdUrsids

December

107

[8] and 1994 (lo ¼ 270.080 ) [9]. Peak time of nodes explained from w1000-y old trails shifted by 0.1 [10]. Model of Filament outbursts in [15], predicted 2007 return, confirmed by airborne observations. Review of video observations by [20], annual activity in Fig. 4.21. Name and number by [14]. References: [1] Hershell A. S. (1875) Rep. of the 44th Meeting of the British Assoc. for the Adv. Sci. 44, 270 (and pp. 358e359); [2] Denning W. F. (1916) Observatory 39, 466e467; [3] Becvár A. (1946) IAU Circular 1026, issued February 4, Boston: CBAT, pp. 1e1; [4] Ceplecha Z (1951) BAC 4, 156e160; [5] Clegg J. A., Hughes V. A., Lovell A. C. B. (1948) JBAA 58, 134e139; [6] Hillestad T. E. (1987) JIMO 15, 59e60; [7] Roggemans P. (1987) JIMO 15, 50e53; [8] Veltman R. (1983) Radiant, J. of the DMS 3, 4e9; [9] Ohtsuka H., Shioi H., Hidaka E. (1995) JIMO 23, 69e72; [10] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 263e270; [11] Jenniskens P., et al. (2002) Icarus 159, 197e209; [12] Jenniskens P. (2000) IAUCircular 7544, December 18, 2000, Ed.: D.W.E. Green, Boston: CBAT, 1 pp; [13] Jenniskens P., Lyytinen E. (2001) JIMO 29, 41e45; [14] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [15] Jenniskens P., et al. (2007) JIMO 35, 125e133; [16] Jenniskens P. (1994) AA 287, 990e1013; [17] Rendtel J. (2022) IMO 2022 Meteor Shower Calendar. Potsdam: IMO, p. 20e20; [18] Molau S., et al. (2014) JIMO 42, 76e82; [19] Molau S., et al. (2013) JIMO 41, 52e60; [20] Roggemans P. (2021) eMeteorNews 6, 1e14; [21] Moreno-Ibánez M., et al. (2017) MNRAS 468, 2206e2213; [22] Jenniskens P. (2014) CBET 4041, Ed.: D.W.E. Green, Cambridge:CBAT, 1 pp.

Jan. 3 (lo ¼ 283 )

10 QUA d Quadrantids

Dynamic type: Jupiter-family comet, part of Machholz Complex, TJ ¼ þ2.31  0.37 Shower type: Annual shower, variable activity Years of high rates: 2001e2016: 2002, 2004, 2014, 2016 [28]; 2019 [29] Period of activity: December 23eJanuary 14 (lo ¼ 271 e294 ) Shower radiant/speed lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) Median (geocentric): 283.1 229.6 þ49.8 276.2 þ63.8 40.4 Drift per day (d/dlo): þ0.86 0.38 þ0.54 þ0.04 0.04 Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Median: 2.72 0.979 0.641 70.8 172.6 283.1 95.8 eV 1 Dispersion (±s): 0.0029 0.056 1.82 3.50 0.31 3.50 ) 2 Dispersion (±s): 0.0091 0.048 3.10 10.2 4.4 10.2 ) 2 Drift (d/dlo): þ0.0002 0.0006 0.07 0.50 þ1.00 þ0.50 ) 1 Number observed: N ¼ 13,591 (hr ¼ 44.1 , m(Mv ¼ 0) ¼ 0.07 g) ) core; 2) background Time of peak activity: lo ¼ 283.15 e283.30 in strong years, lo ¼ 283.05 in weak years [28] Peak ZHR: 1980e1990: 70e120/h, var.; core: ZHR ¼ 110  20/h, bkg: ZHR ¼ 20  4 [22] 2020e2022: ZHR ¼ 70e138/h [32] Magn. distribution index: c ¼ 2.48  0.02 (s ¼ 1.99  0.01); 2.5 [22]; Peak: c ¼ 2.1, 2.5 elsewhere [24] Lightcurve: IIa: Hb ¼ 100.4  0.61 Mv; Hmax ¼ 92.9 þ 1.24 Mv; He ¼ 88.0 þ 1.71 Mv (N ¼ 5006) Meteoroid density: r ¼ 1.9  0.2 g/cm3, porosity K ¼ 44% [16]; same as rgrain for m ¼ 2 kg [25]; r ¼ 2.6  0.1 g/cm3, K ¼ 15% grain size 80e300 mm, for m ¼ 105 to 104 g [25] dNa poor IIa: r w 1.23  0.14 g/cm3 (a1 ¼ 0.093 km, a2 ¼ 4.67/s) Spectroscopy: Mg0.82 Fe1.09 Na0.018 (N ¼ 9), Na depleted for Mv > 2; Na depleted, more so for m < 104 g [25]; m > 3  104 g: Normal Na/Fe despite low q in past [15]; early release of Na when small [26] Age: Core: w529 y [11]; 200e250 y [17], 2003 EH1 q-cycle minimum 1300 y ago [18] Background: 6500 y [21], few 1000 y [20]; sU < su Source: (196256) 2003 EH1 Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Epoch 2022-Jan-21.0 TDB 3.12 1.192 0.618 70.8 171.3 283.0 94.3 Source: C/1491 Y1 [23] Epoch 1923-Nov-18.3 TDB 3.04 0.769 0.747 70.2 164.0 283.0 87.0 Source: 96P/Machholz 1 Epoch 2008-Nov-03.0 TDB 3.03 0.123 0.959 58.5 14.7 94.4 109.1

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December

109

Brief history: Observations in 1825 [1], 1835 and 1838 [2] suggested that early morning of January 2 often saw many meteors. First visually determined radiant by [3] from R.A. ¼ 238.0 , Decl. ¼ þ46.4 (B1850) in constellation Quadrans Muralis. Other visual observations summarized by [4] had variable rates. First photographic radiant on January 2/3, 1929, by [5] from three single-station trails: R.A. ¼ 231.8 , Decl. ¼ þ48.3 (Eq. B1900.0). First radar observations by [6]. [7] determined FWHM of shower of only 16 h. Model by [8] first showed large variation of orbital elements over time with a period of w4000 y. Linked to 96P by [19], which has same 4000 y quasiperiodical cycles as Quadrantids, but shifted FIG 4.22 ZHR profile, dashed line by [22]. by 2000 y. Link to other Machholz showers suggested by [9]. First large number of precisely reduced orbits by [10] suggested young stream age (w500 y) and clustering in the 2:1 (inclination ¼ 71.4 ), 2:3 (i ¼ 72.8 ), and 3:5 (i ¼ 71.9 ) meanmotion resonances. An estimate of the parent body orbit was provided. Following the discovery of new near-Earth object 2003 EH1 at Lowell Observatory on March 6, 2003 [11] identified this object as the Quadrantid parent body in October that year. Proposed formation of stream in breakup perhaps associated with sighting of comet C/1491 Y1, which was later shown to be a short period comet by [23]. [27] integrated parent and QUA orbits back in time and confirmed convergence around 1500 CE. Younger w200 y age for core proposed by [12,15]. Model by [31] predicts variable peak time and activity due to Jupiter passing close to QUA orbit near aphelion. Strong years included the lo ¼ 283.146 and ZHR ¼ 119  6/h of 2019 [30]. [10] noted activity curve has a narrow main component and a broader background (Fig. 4.22). Background possibly related to 96P activity or ongoing fragmentation cascade in Machholz family. Called “Filament 5” in model of 96P ejecta by [18]. Name by [13], number by [14]. References: [1] Brucalassi A. (1825) Antologia 17, 135; [2] Wartmann L. F., Reynier E. (1839) Correspondance Mathématique et Physique de l’Observatoire de Bruxelles 11, 351; [3] Masterman S. (1863) American J. of Sci and Arts, 2nd Ser. 35, 149e150; [4] Fisher W. J. (1930) Harvard College Observatory Circular 346, 1e11; [5] Fisher W. J., et al. (1930) Harvard College Observatory Circular 347, 1e4; [6] Hawkins G. S., Almond M. (1952) MNRAS 112, 219e233; [7] Hindley K. B. (1972) Sky & Telescope 43, 162e164; [8] Hamid S. E., Youssef M. N. (1963) SCoA 7, 309e311; [9] Hamid S. E., Whipple F. L. (1963) AJ 68, 537e537; [10] Jenniskens P., et al. (1997) AA 327, 1242e1252; [11] Jenniskens P. (2004) AJ 127, 3018e3022; [12] Wiegert P. A., Brown P. G. (2004) EMP 95, 81e88; [13] Backhouse T. W. (1883) Nature 29, 104e104; [14] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [15] Borovicka J., et al. (2005) Icarus 174, 15e30; [16] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [17] Wiegert P., Brown P. (2015) Icarus 179, 139e157; [18] Neslusan L., Hajduková M., Jakubík M. (2015) AA 560, A47eA56; [19] McIntosh B. A. (1990) Icarus 86, 299e304; [20] Kanuchová Z., Neslusan L. (2007) AA 470, 1123e1136; [21] Babdzhanov P. B., Obrubov Yu. V. (1992) In: Asteroids, Comets, Meteors 1991. Eds.: A. Harris, E. Bowell, Tucson: Lunar and Planetary Inst., pp 27e32; [22] Jenniskens P. (1994) AA 287, 990e1013; [23] Lee K.-W., Yang H.-J., Park M.-G. (2009) MNRAS 400, 1389e1393; [24] Rendtel J. (2021) IMO Meteor Shower Calendar 2022. Potsdam: IMO, p. 4e4; [25] Borovicka J., et al. (2009) In: Proc. IAU Symp. 263, Ed.: Fernandez J. A., et al., Cambridge: IAU/CUP, p. 218e222; [26] Koten P., et al. (2006) MNRAS 366, 1367e1372; [27] Williams I. P., Ryabova G. O., Baturin A. P., Chernitsov A. M. (2004) MNRAS 355, 1171e1181; [28] Ogawa H., Steyaert C. (2017) JIMO 47, 98e106; [29] Molau S., et al. (2021) JIMO 49, 15e18; [30] Miskotte K. (2020) eMeteorNews 189e191; [31] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 357e376; [32] Vida D., et al. (2022) MNRAS 515, 2322e2339.

110

The Atlas: Overview and major showers

January

Dec. 31 (lo ¼ 279 )

758 VOL d Volantids

Dynamic type: Shower type: Year of outbursts:

Jupiter-family comet, TJ ¼ þ2.57  0.26 Episodic shower 2015: lo ¼ 280.3  0.2 , W w 1.5 , c ¼ 2.17  0.17 [1] 2020: lo ¼ 280.0  0.1 , W ¼ 1.6  0.2 [6] December 27eJanuary 1 (lo ¼ 276 e283 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 279.3 123.4 72.1 301.1 77.2 30.4 0.96 0.88 þ3.36 0.04 0.17 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.81 0.973 0.654 50.5 347.1 99.3 86.5 0.0028 0.0661 1.72 1.96 1.48 1.96 0.0016 0.0071 0.45 0.98 þ1.00 þ0.02 N ¼ 205 (hr ¼ 47.9 , m(Mv ¼ 0) ¼ 0.15 g) var.; 2020: ZHR ¼ 10  4 [4] c ¼ 3.02  0.13 (s ¼ 2.20  0.05) Component IIa has low He with Ke < 79: IIa: Hb ¼ 97.6  1.64 Mv; Hmax ¼ 84.5  1.79 Mv; He ¼ 78.4 þ 2.63 Mv (N ¼ 146) IIa: r w 2.5  0.7 g/cm3 (a1 ¼ 0.076 km, a2 ¼ 4.11/s) e e

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

111

eV

Brief history: New Year’s Eve shower on the Southern Hemisphere. Meteors radiate from the constellation Volans, first introduced as “Pisces Volans” on star maps by Dutch cartographer Petrus Plancius in 1598. The name translates as “the flying fish” [1]. Shower first detected by CAMS New Zealand low-light video camera network on December 31, 2015 [1], from a radiant at R.A. ¼ 120.6 , Decl. ¼ 72.0 and Vg ¼ 28.4 km/s centered on lo ¼ 279.197 . Confirmed by VHF wind radar by [2], which recorded the shower for several additional days. Photographically detected by Desert Fireball Network [3]. Independently identified in SAAMER radar data by [7] and entered in Working List as #787. Not detected FIG 4.23 2020 ZHR profile (video: •, visual þ) in following years, but re-emerged on December 27 and 28, 2020, when the Southern Hemisphere [5], compared to 2015 radar activity profile [2]. CAMS networks spotted the first Volantids of the 2020 return and an outburst alert was issued [5,8]. Summary of the observations by [4]. Fig. 4.23 compares the 2020 ZHR profile to the activity detected in 2015 (uncertain vertical scale), suggesting an earlier maximum in 2020. Name and number by [1]. References: [1] Jenniskens P., Baggaley W. J., Crumpton I., Aldous P., Gural P. S., Samuels D., Albers J., Soja R. (2016) JIMO 44, 35e41; [2] Younger J., Reid I., Murphy D. (2016) In: Proceedings International Meteor Conference, Egmond, the Netherlands, 2e5 June 2016, Eds.: Roggemans A., Roggemans P., Mechelen: IMC, pp. 352e357; [3] Jenniskens P., et al. (2018) PSS 154, 21e29; [4] Jenniskens P., Cooper T. (2021) eMeteorNews 6, 262e263; [5] Jenniskens P. (2020) CBET 4901, D. W. E. Green (ed.), Boston: CBAT, issued 2020 December 29, 1pp.; [6] Jenniskens P. (2020) CBET 4923, D. W. E. Green (ed.), Boston: CBAT, issued 2021 January 24, 1pp; [7] Pokorny P., et al. (2017) Icarus 290, 162e182; [8] Jenniskens P. (2021) eMeteorNews 6, 21e23.

112

The Atlas: Overview and major showers

113

January

Jan. 19 (lo ¼ 299 )

404 GUM d gamma Ursae Minorids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.67  0.20 Annual shower, periodic outbursts 2010: lo ¼ 300.7 , c ¼ 1.65  0.35 [4] January 15e25 (lo ¼ 295 e305 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 299.5 229.0 þ67.6 217.8 þ74.1 29.3 þ1.13 0.88 þ2.61 0.18 þ0.28 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.70 0.952 0.649 48.1 203.2 299.5 142.8 eV 0.0059 0.0637 1.85 2.42 1.73 2.42 þ0.0021 0.0042 þ0.47 0.72 þ1.00 þ0.28 N ¼ 286 (hr ¼ 44.7 , m(Mv ¼ 0) ¼ 0.16 g) w0.6/h; 3/h [6]; 0.7/h c ¼ 2.89  0.43 (s ¼ 2.17  0.15); 3.0 [6] Component IIa has low He: Ke < 79: IIa: Hb ¼ 96.8 þ 0.87 Mv; Hmax ¼ 86.6 þ 1.03 Mv; He ¼ 80.2 þ 2.22 Mv (N ¼ 141) IIa: r w 3.4  1.0 g/cm3 (a1 ¼ 0.045 km, a2 ¼ 4.02/s) e 8P/Tuttle duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.70 1.027 0.820 55.0 207.5 270.3 117.8

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2008-Jul-18.0 TDB

Brief history: First identified by [1] from 694 CMOR radar orbits having R.A. ¼ 231.8 , Decl. ¼ þ66.8 , and Vg ¼ 31.8 km/s around lo ¼ 299.0 . Confirmed from single-station video observations by [2] and triangulations by [3,4]. Eight prediscovery orbits from the Harvard Radio Meteor Patrol identified by [8]. Finnish Meteor Network video observers detected an outburst of bright meteors (þ0.55 mean magn.) on January 20/ 21, 2010, (lo ¼ 300.7 ) from R.A. ¼ 228.0 , Decl. ¼ þ66.4 and Vg ¼ 29.6 km/s [4]. Compact radiant in video data from 2016: R.A. ¼ 228.5 , Decl. ¼ þ67.8 [7]. ZHR profile in Fig. 4.24. Source proposed as 8P/Tuttle by [5]. Name and number by [1]. FIG 4.24

ZHR profile.

References: [1] Brown P., et al. (2008) Icarus 195, 317e339; [2] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [3] Madiedo J. M., Trigo-Rodriguez J. M., Lyytinen E., Pujols P. (2011) EPSC Abstracts 6, EPSC-DPS2011-65-2; [4] Jenniskens P. (2010) CBET 2146, Ed.: D. W. E. Green, Cambridge: Central Bureau for Astronomical Telegrams, 1e1 pp; [5] Brown P., et al. (2010) Icarus 207, 66e81; [6] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [7] Molau S., et al. (2017) JIMO 45, 63e66; [8] Greaves J. (2012) JIMO 40, 53e58.

114

The Atlas: Overview and major showers

115

February

Feb. 4 (lo ¼ 315 )

427 FED d February eta Draconids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ0.89  0.48 Annual shower, perhaps with episodic outbursts 2011, 2014, 2020? February 2e6 (lo ¼ 313 e317 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 315.2 239.6 þ62.0 229.8 þ76.2 35.2 þ0.69 þ0.33 1.36 þ0.46 0.29 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 27.0 0.971 0.964 55.4 194.3 315.2 149.4 0.0042 0.089 1.53 2.02 0.62 2.02 þ0.0007 þ0.0026 0.60 0.25 þ1.00 þ0.75 N 0.971 1.000 55.2 194.1 315.1 149.2 N ¼ 139 (hr ¼ 49.6 , m(Mv ¼ 0) ¼ 0.10 g) ZHR w 1.6/h; 0.5/h [4] c ¼ 2.45  0.20 (s ¼ 1.97  0.04) Ib: Hb ¼ 104.4  0.55 Mv; Hmax ¼ 97.1 þ 0.99 Mv; He ¼ 92.8 þ 1.51 Mv (N ¼ 87) Ib: r w 0.67  0.31 g/cm3 (a1 ¼ 0.094 km, a2 ¼ 5.23/s) From c and s: w20,000 y; From model w17,000 y; sU < su: Earth through core e

FIG 4.25 ZHR profile (•), vertical scale uncertain.

FIG 4.26

eV e V[1]

Shower #427 on February 04, 2022.

Brief history: First shower identified from CAMS low-light video triangulations [1], based on only 6 meteors from a compact radiant at R.A. ¼ 239.9 , Decl. ¼ þ62.5 and Vg ¼ 35.6 km/s around lo ¼ 315.11 in the year 2011. Confirmed from about 150 single-station video data by [2] and from multi-station data by [3]. Prediscovery detection from single-station video data by [5], when it was the most active radiant on the day of lo ¼ 315 , suggesting annual activity [4]. Now 139 meteors from this radiant have been triangulated, shower confirmed to return annually here, with some years more detections than others. Radiant distribution has a compact core and wide halo. A possible asymmetry in the activity profile (Fig. 4.25) suggests that meteors around solar longitude 315 may be due to irregular activity. Position of the shower radiant in Draco shown in Fig. 4.26. Name and number by [1]. References: [1] Jenniskens P., Gural P. S. (2011) JIMO 39, 93e97; [2] Molau S., et al. (2013) JIMO 41, 92e95; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Molau S., et al. (2012) JIMO 40, 101e105; [5] Molau S., Rendtel J. (2009) JIMO 37, 98e121.

116

The Atlas: Overview and major showers

January

117

Jan. 30 (lo ¼ 310 )

569 OHY d omicron Hydrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.13  0.51 Annual shower January 12eFebruary 14 (lo ¼ 291 e325 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 309.6 177.5 34.2 243.1 32.1 59.2 þ0.95 0.35 þ0.10 þ0.06 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.0 0.680 0.922 114.3 69.4 129.5 199.9 eV 0.0515 0.106 3.85 8.24 7.41 8.24 0.0003 0.0006 þ0.11 þ0.05 þ1.00 þ1.05 1.0  0.2 (N ¼ 1196, hr ¼ 49.4 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 4.20  0.36 (s ¼ 2.56  0.10) Ia: Hb ¼ 115.3  1.88 Mv; Hmax ¼ 103.5 þ 0.52 Mv; He ¼ 98.1 þ 0.95 Mv (N ¼ 178) Ib: Hb ¼ 110.3  1.69 Mv; Hmax ¼ 99.7 þ 0.72 Mv; He ¼ 94.7 þ 1.19 Mv (N ¼ 709) II: Hb ¼ 103.7  2.10 Mv; Hmax ¼ 93.9 þ 0.99 Mv; He ¼ 89.2 þ 1.32 Mv (N ¼ 52) Ia: r w 0.95 g/cm3 (a1 ¼ 0.081 km, a2 ¼ 3.38/s) dpossibly Fe poor Ib: r w 0.73  0.18 g/cm3 (a1 ¼ 0.051 km, a2 ¼ 7.37/s) II: r w 1.7 g/cm3 (a1 ¼ 0.265 km, a2 ¼ 9.95/s) dpossibly Na poor/free From c and s: w> 95,000 y; From model: w140,000 y; high dP/dlo versus i 109P/Swift-Tuttle duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 26.1 0.960 0.963 113.5 153.0 139.4 292.4 C/770 K1 duncertain N 0.580 1.000 117.0 88.0 110.7 198.7

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 1995-Oct-10.0 TDB Source: Epoch 2008-Nov-03.0 TDB

Brief history: Known from past visual observations, the shower was first entered in IAU list as #316, but no velocity information was known at the time. First instrumentally detected #569 from 29 Croatian Meteor Network and SonotaCo network meteors by [1], with R.A. ¼ 176.4 and Decl. ¼ 34.1 and Vg ¼ 59.1 km/s around lo ¼ 309 . Confirmed by [2]. In the same direction at that time is a stream #1183 with small semi-major axis. Link to 109P by [3]. Possible link to 770 K1 here. Activity curve shown in Fig. 4.27. Name and number by [1].

FIG 4.27

ZHR profile.

References: [1] Andreic Z., Gural P., Segon D., Skokic I., Korlevic K., Vida D., Novoselnik F., Gostinski D. (2014) JIMO 42, 90e97; [2] Jenniskens P., et al. (2016) Icarus 266, 355e370; [3] Neslusan L., Hajduková M. (2022) Icarus 382, id.115015.

118

The Atlas: Overview and major showers

February

Feb. 15 (lo ¼ 326 )

1047 GCR d gamma Crucids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.33  0.42 Annual shower February 12e19 (lo ¼ 323 e330) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 325.9 197.2 56.0 255.5 44.1 56.0 þ1.84 0.09 þ0.27 þ0.47 þ0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.15 0.929 0.900 102.8 29.3 145.9 175.2 0.0119 0.0990 1.48 3.44 1.54 3.44 þ0.0000 0.0156 þ0.66 þ0.19 þ1.00 þ1.19 w1/h; w3/h [4] (N ¼ 203, hr ¼ 53.2 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.93  0.19 (s ¼ 2.17  0.07) I: Hb ¼ 111.6  1.07 Mv; Hmax ¼ 102.5 þ 1.37 Mv; He ¼ 97.2 þ 1.87 Mv (N ¼ 197) III: Hb ¼ 97.2 þ 0.00 Mv; Hmax ¼ 93.7 þ 0.47 Mv; He ¼ 89.9 þ 0.22 Mv (N ¼ 5) I: r w 0.35  0.17 g/cm3 (a1 ¼ 0.044 km, a2 ¼ 8.40/s) III: Likely Na poor/free From c and s: w55,000 y; From model: w56,000 y; high dP/dlo versus i omicron Centaurids e

Meteoroid density: Age: Alternative name: Source:

119

eV

Brief history: Perhaps first detected in visual observations by [7] from Namibia in the 1930’s, but regular visual observations only after the 1971 detection by [6] of the Astronomical Society of Western Australia (ASWA), observing from Mt. Gungin, Western Australia, during 4e14 February, when they recorded a maximum of 4e5 meteors per hour on the night of February 11/12. From this time on, the g-Crucids were regularly observed up until the mid-1990s, extending from around February 2 to 19, yellow or yelloweorange in color with some of the brighter ones having a short duration train, and radiating from R.A. ¼ 178  10 ,   Decl. ¼ 55  4 , about 10 West of the radiant measured here. Detected in routine CAMS lowFIG 4.28 ZHR profile. light video observations in 2021 and reported by [1,2]. Perhaps not an outburst as thought at the time, because the radiant remained diffuse and significant numbers were also seen in 2020 and 2022. Combined activity curve in Fig. 4.28. The yearly tally starting in 2015: 2, 2, 9, 0, 3, 31, 71, 52, 98, with a much increased numbers of cameras in the CAMS network after 2019. The meteors radiated from R.A. ¼ 192.6  3.3 and Decl. ¼ 56.0  1.6 and Vg ¼ 55.8  1.7 km/s around  lo ¼ 324.21  0.99 . It is not likely a return of the 1980 February 8/9 a-Centaurids (#102). That event was of much shorter duration with FWHM w0.3 h and rich in bright meteors [4,5]. References: [1] Jenniskens P. (2021) Gamma Crucid meteors 2021. CBET 9432. Ed.: D. W. E. Green, Cambridge: Central Bureau for Astronomical Telegrams, issued February 15, 1pp; [2] Jenniskens P. (2021) eMeteorNews 6, 264e264; [4] Wood J. (1986) NAPO-MS Bulletin #157, Perth: NAPO-MS; [5] Wood J. (1980) Radiant, Journal of the DMS 2, 135e139; [6] Clark M., Buhagiar M. (1971) pers. communication with J. Wood; [7] Hoffmeister C. (1948) Meteorströme. Leipzig: J. A. Barth, 286 pp.

120

The Atlas: Overview and major showers

121

February

Dec. 29 (lo ¼ 277 )

331 AHY d alpha Hydrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.86  0.33 Annual shower December 3eJanuary 25 (lo ¼ 251 e305 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 277.1 122.4 9.2 209.7 28.0 43.8 þ0.67 þ0.06 0.27 þ0.22 0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.17 0.314 0.965 61.5 112.9 97.1 211.3 eV 0.0641 0.0598 4.67 8.52 10.54 8.52 0.0029 þ0.0007 0.48 þ0.32 þ1.00 þ1.32 January 1 (lo ¼ 281 ) N ¼ 3231 (hr ¼ 42.9 , m(Mv ¼ 0) ¼ 0.06 g) ZHR ¼ 0.9/h; w2/h [6] c ¼ 2.94  0.07 (s ¼ 2.17  0.03); 2.8 [6] Ib: Hb ¼ 106.2  1.02 Mv; Hmax ¼ 96.0 þ 1.05 Mv; He ¼ 90.9 þ 1.50 Mv (N ¼ 1479) II: Hb ¼ 99.4  0.65 Mv; Hmax ¼ 91.3 þ 1.01 Mv; He ¼ 86.9 þ 1.22 Mv (N ¼ 175) III: Hb ¼ 93.7  0.16 Mv; Hmax ¼ 89.1 þ 0.70 Mv; He ¼ 84.9 þ 0.92 Mv (N ¼ 333) Ib: r w 0.78  0.21 g/cm3 (a1 ¼ 0.0715 km, a2 ¼ 5.00/s) dpossibly Na poor II: r w 1.4  0.4 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 6.43/s) III: r w 1.9  0.5 g/cm3 (a1 ¼ 0.056 km, a2 ¼ 8.81/s) dpossibly Na free

Meteoroid density:

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

December 21eJanuary 18 (lo ¼ 270 e298 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 281.7 126.4 6.0 208.5 þ0.71 0.14 0.21 a (AU) q (AU) e i ( ) 3.15 0.252 0.930 54.3 0.0310 0.0515 6.78 þ0.0009 þ0.0017 0.40 12.7 0.287 0.977 57.1 N ¼ 117

Age: Source:

From c: w14,000 y; from s w 26,000 y; From model: w65,000 y e

b ( ) 24.5 þ0.05 u ( ) 123.8 5.83 0.23 115.6

Vg (km/s) 41.3 0.02 U ( ) 101.7 5.79 þ1.00 105.0

P ( ) 224.7 5.83 þ0.77 211.3

e R[M] e R[1]

Brief history: Known from past visual observations [6]. First detected instrumentally from 2002 to 2006 CMOR radar data by [1] from R.A. ¼ 127.6 , Decl. ¼ 7.9 and Vg ¼ 43.6 km/s around lo ¼ 285.5 . [2] extended the activity range from lo ¼ 267 to 300 . Video data show a longer duration (Fig. 4.29). Confirmed by [3] from single station video observations, and by [4,5] from video triangulations. Name and number by [1].

FIG 4.29

ZHR profile.

References: [1] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [2] Brown P., et al. (2010) Icarus 207, 66e81; [3] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [4] Kanamori T. (2009) JIMO 37, 55e62; [5] Jenniskens P., et al. (2016) Icarus 266, 331e354; [6] Jenniskens P. (1994) AA 287, 990e1013.

122

The Atlas: Overview and major showers

March

123

March 3 (lo ¼ 343 )

571 TSB d 26 Bootids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2015-May-19.0 TDB

Long period comet; TJ ¼ þ0.15  0.24 Annual shower, possibly with episodic outbursts February 25eMarch 8 (lo ¼ 337 e347 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 343.3 216.5 þ24.3 221.4 þ36.5 49.8 þ0.77 0.36 0.02 0.04 þ0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 56.9 0.497 0.991 83.1 270.3 343.3 253.4 e V 0.0161 0.0353 0.98 2.63 1.55 2.82 0.0003 þ0.0023 þ0.09 0.02 þ1.00 þ0.98 w0.04/h (N ¼ 90, hr ¼ 57.8 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 1.84  0.11 (s ¼ 1.66  0.07) I: Hb ¼ 109.1  1.27 Mv; Hmax ¼ 96.9 þ 0.94 Mv; He ¼ 91.5 þ 1.44 Mv (N ¼ 30) I: r ¼ 1.1  0.5 g/cm3 (a1 ¼ 0.014 km, a2 ¼ 5.82/s) From s: 18,000 y; from c: young shower; From model: w27,000 y C/868 B1 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.420 (1.000) 65.0 277.0 321.0 238.0

Brief history: The shower was first described from a compact cluster of 10 triangulated meteors over 4 days in low-light video observations by the Croatian Meteor Network and the SonotaCo network by [1]. Meteors radiated from R.A. ¼ 217.6 , Decl. ¼ þ24.0 and Vg ¼ 49.7 km/s around lo ¼ 344.0 . Members of this shower were very bright, with a mean magnitude of about 1.6. Shower confirmed here from 90 triangulated low-light video meteors, providing an activity profile shown in Fig. 4.30 and a low magnitude distribution index. The orbit shows only a vague resemblance to that of C/868 B1, but that orbit is uncertain [2]. Name and number by [1]. FIG 4.30

ZHR profile.

References: [1] Andreic Z., et al. (2014) JIMO 42, 90e97; [2] Kronk G. W. (1999) Cometography, a Catalog of Comets. Cambridge: CUP, p. 134e136.

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March

125

March 16 (lo ¼ 357 )

11 EVI d eta Virginids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.97  0.16 Episodic shower (1942, 1950/1) 1953, (1957/8, 1968/9, 1978, 1986) 2009/10, 2013/4, 2017/8, 2021 March 8e25 (lo ¼ 347e4 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 357.0 185.1 þ3.7 186.2 þ5.4 26.9 þ0.63 0.20 0.34 þ0.06 0.20 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.43 0.453 0.815 5.36 282.2 357.1 279.4 eV 0.0586 0.0444 0.61 6.74 3.55 6.74 þ0.0058 0.0020 0.01 0.66 þ1.00 þ0.33 2.50 0.451 0.819 5.3 282.3 354.6 276.9 e [6]* w12/h (N ¼ 955, hr ¼ 47.8 , m(Mv ¼ 0) ¼ 0.20 g) *) Ten 4 to 11 fireballs c ¼ 2.25  0.04 (s ¼ 1.88  0.02) Components II has low He [6], Ke < 79, like III: II: Hb ¼ 94.7  0.90 Mv; Hmax ¼ 84.2 þ 1.34 Mv; He ¼ 78.3 þ 2.31 Mv (N ¼ 615) IIIb: Hb ¼ 85.7  2.07 Mv; Hmax ¼ 76.9  0.16 Mv; He ¼ 72.4 þ 0.57 Mv (N ¼ 5) II: r ¼ 2.62  0.49 g/cm3 (a1 ¼ 0.101 km, a2 ¼ 3.34/s); 3.5 g/cm3 [7] PE coefficient: 75% I, 15% II, 10% IIIA (N ¼ 10) [7] dcompact material II: Mg1.56 Fe1.09 Na0.058 (N ¼ 2) e 2003 FB5 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.52 0.532 0.789 5.35 288.3 358.4 286.7

Meteoroid density: Meteoroid strength: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2020-Oct-17.0 TDB

Brief history: Shower is irregular. While “Virginids” were long known by visual observers to radiate from the anthelion source in March and April, it is not clear when individual Virginid showers were first detected by visual observers. [1] found a radiant at R.A. ¼ 178 , Decl. ¼ þ7 (Equinox of date) from observations during March 1e15 in 1849e1859. [2] reported that J. F. J. Schmidt observed 11 meteors from R.A. ¼ 181 , Decl. ¼ þ6 (Equinox of date) in the month of March during 1858e1863 [1]. [3] reported a “Virginid Current” from the direction of other “Ecliptical Currents” (anthelion source) at R.A. ¼ 193.4 , Decl. ¼ 1.9 around lo ¼ 355.7 from observations made during 1908e1938. Only in 1953, during the 1952e1954 Super-Schmidt photographic program [4], were five orbits measured that FIG 4.31 ZHR from multiyear video. appear to be EVI (see also [9]). They radiated from R.A. ¼ 181 , Decl. ¼ þ0 and Vg ¼ 25.8 km/s during lo ¼ 351e353 , called “Virginids”. None detected in 1952 and 1954. Video shows narrow shower in b. Activity curve in Fig. 4.31. From SonotaCo data, 4-year period by [8] close to the 3:1 mean-motion resonance with Jupiter (3.95 y). Here, video orbit tally starting in 2007: 1, 0, 61, 21, 8, 12, 146, 120, 19, 34, 108, 52, 21, 75, 277, period of 4.01  0.12 years, with the 2021 outburst at revolution #18 if 1953 is #1. Possible parent 2003 FB5 identified here (H ¼ 23.5m, Tj ¼ 2.92, P ¼ 3.99 y). Many other candidates due to orbit similarity to evolved asteroid orbits, but not as good a match. Number assigned by [4,5], name by [6]. References: [1] Heis E. (1864) MNRAS 24, 212e215; [2] Heis E., Neumayer G. (1867) On Meteors in the Southern Hemisphere. Mannheim: J. Schneider, 25pp. (p. 15); [3] Hoffmeister C. (1948) Meteorströme. Leipzig: Verlag Werden und Werken Weimar, p. 138; [4] McCrosky R. E., Posen A. (1961) SCoA 4, 15e84; [5] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [6] Jenniskens P. (2006) Meteor showers and their Parent Comets. Cambridge: CUP, Ch. 28; [7] Brcek A., et al. (2021) JIMO 49, 98e101; [8] Shiba Y. (2018) JIMO 46, 184e190; [9] Koseki M. (2019) JIMO 47, 139e150.

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0 SPO e Sporadic meteors.

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March

March 29 (lo ¼ 7 )

647 BCO d beta Comae Berenicids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.35  0.17 Annual shower February 27eApril 17 (lo ¼ 338 e27 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 7.3 194.2 þ24.9 175.5 þ28.4 27.0 þ0.88 þ0.06 0.22 þ0.40 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 13.2 0.640 0.946 22.1 250.5 7.3 257.8 eV 0.0291 0.0841 1.98 3.79 9.83 3.79 þ0.0045 0.0001 þ0.19 0.60 þ1.00 þ0.40 w0.1/h (N ¼ 598, hr ¼ 59.0 , m(Mv ¼ 0) ¼ 0.19 g) c ¼ 2.35  0.09 (s ¼ 1.93  0.04) Component Ib has low He, ke < 79, like III: Ib: Hb ¼ 100.2  0.68 Mv; Hmax ¼ 89.5 þ 1.06 Mv; He ¼ 84.5 þ 1.59 Mv (N ¼ 304) IIb: Hb ¼ 91.7  0.50 Mv; Hmax ¼ 84.9 þ 0.99 Mv; He ¼ 79.5 þ 1.83 Mv (N ¼ 47) III: Hb ¼ 86.9  0.92 Mv; Hmax ¼ 82.3 þ 0.44 Mv; He ¼ 78.3 þ 1.03 Mv (N ¼ 21) Ib: r w 0.91  0.25 g/cm3 (a1 ¼ 0.0945 km, a2 ¼ 3.48/s) IIb: r w 2.3 g/cm3 (a1 ¼ 0.078 km, a2 ¼ 4.44/s) dpossibly Na free or iron III: r w 1.6 g/cm3 (a1 ¼ 0.344 km, a2 ¼ 4.58/s) dpossibly Na poor/free From c: w13,000 y; from s: w41,000 y; radiant drift dU > du; From model: w10,000 y, precession takes stream across Earth’s orbit e

Meteoroid density:

Age: Source:

FIG 5.1

ZHR profile.

Brief history: A well-defined shower first reported by [1] from a cluster of about 30 triangulated meteors in 2010e2015 CAMS data, confirmed by a similar group of about 17 meteors in 2007e2013 SonotaCo low-light video data. Six of the CAMS radiants were tightly clustered within that distribution at R.A. ¼ 196.2 , Decl. ¼ þ24.9 with Vg ¼ 27.3 km/s centered on lo ¼ 9 . There is a significant radiant motion in Sun-centered ecliptic coordinates. Because of the low inclination of the orbit, there is a strong precession. The shower emerges from the anthelion source at a latitude of b w 16 around lo ¼ 345 , after which the radiant moves north-west to a latitude of b w 36 around lo ¼ 25 . No past observations are known. The activity curve is shown in Fig. 5.1. The source is unknown. Name and number assigned by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

April 11 (lo ¼ 22 )

697 BEA e April beta Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo):

Long-period comet, TJ ¼ -0.56  0.64 Annual shower April 2 e 19 (lo ¼ 13 e 30 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 21.5 267.5 16.3 243.8 +0.78 0.13 0.24

b ( ) þ7.4 0.11

Vg (km/s) 65.9 0.07

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March

April 11 (lo ¼ 22 )

697 BEA e April beta Aquariids (cont.)

Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

a (AU) 22.7

q (AU) e i ( ) u ( ) U ( ) P ( ) 0.520 0.970 163.6 268.7 21.5 290.2 0.0407 0.0817 1.39 6.60 4.46 6.60 0.0066 þ0.0013 þ0.16 þ0.74 þ1.00 þ1.74 w0.1 /h (N ¼ 301, hr ¼ 42.6 , m(Mv¼0) ¼ 0.02 g) c ¼ 3.81  0.11 (s ¼ 2.45  0.03) I: Hb ¼ 113.6  1.31 Mv; Hmax ¼ 101.6 + 1.44 Mv; He ¼ 96.8 þ 1.92 Mv (N ¼ 227) I: r w 0.43 g/cm3 (a1 ¼ 0.058 km, a2 ¼ 7.65 /s) From c and s: w56,000 y -.-

eV

Brief history: First reported by [1] from 31 triangulated SonotaCo-detected meteors with a radiant at R.A. ¼ 266.3 , Decl. ¼ 15.9  with Vg ¼ 65.9 km/s around lo ¼ 22.1 . Designation assigned: M2023-F3. Low i and q cause rapid rotation of nodal line. Number and name here. References: [1] Shiba Y. (2023) JIMO, submitted. March 19 (lo ¼ 356 )

792 MBE d March beta Equuleids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, sunskirter, TJ ¼ þ0.42  0.37 Annual shower March 128 (lo ¼ 340 e8 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 355.5 317.6 þ5.0 325.7 þ19.9 48.1 þ0.84 þ0.23 0.07 0.04 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 26.2 0.167 0.994 73.9 48.1 355.5 44.2 eV 0.0154 0.0178 5.16 2.77 6.59 2.77 0.0008 0.0003 þ0.17 0.14 þ1.00 þ0.86 N ¼ 45 (hr ¼ 18.2 , m(Mv ¼ 0) ¼ 0.05 g) w0.3/h c ¼ 3.83  0.25 (s ¼ 2.46  0.07) Component IIa has high end height, Ke > 82: I: Hb ¼ 110.25  1.26 Mv; Hmax ¼ 100.7 þ 0.26 Mv; He ¼ 97.0 þ 0.52 Mv (N ¼ 18) IIa: Hb ¼ 103.5  2.75 Mv; Hmax ¼ 96.7  0.21 Mv; He ¼ 90.9 þ 1.03 Mv (N ¼ 7) I: r w 1.6 g/cm3 (a1 ¼ 0.333 km, a2 ¼ 1.38/s) dlow number IIa: Probably Na poor/free

Meteoroid density: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

March 16e23 (lo ¼ 355 e2 ) lo ( ) R.A. ( ) Decl. ( ) 357.2 319.4 þ4.7 þ0.66 þ0.27 a (AU) q (AU) e 2.20 0.162 0.945 0.024 0.048 0.0004 0.0048 4.17 0.148 0.965 N ¼ 333

Age:

From c and s: w19,000 y

l ( ) 327.5 0.24 i ( ) 62.8 11.3 0.33 68.8

b ( ) þ19.4 þ0.00 u ( ) 42.8 5.7 0.48 42.8

Vg (km/s) 43.3 0.39 U ( ) 357.3 1.5 þ1.00 359.0

P ( ) 39.8 5.7 þ1.48 41.8

e R[S] e R[1]

Brief history: Shower first reported by [1] from SAAMER radar data at R.A. ¼ 320.9 , Decl. ¼ þ5.0 and Vg ¼ 45.6 km/s around lo ¼ 359.0 . Confirmed here in video observations. Shower rich in faint meteors. No known past visual observations. Name and number assigned by [1]. References: [1] Pokorny P., et al. (2017) Icarus 290, 162e182.

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133

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March

135

March 22 (lo ¼ 1 )

853 ZPA d zeta Pavonids

Dynamic type: Shower type: Years of outbursts:

Long-period comet, TJ ¼ 0.21  0.74 Episodic shower, possibly with annual component 2016: lo w 1.15  0.05 , FWHM ¼ 0.26 , N ¼ 5 [1]; 2020:lo ¼ 1.25  0.05 , FWHM ¼ 0.35 , N ¼ 12 [2,3] 2021: lo ¼ 1.41  0.05 , FWHM ¼ 0.46 , N ¼ 17 [2,3] 2023: lo ¼ 1.40  0.06 , FWHM = 0.44 , N = 9 March 21e22 (lo ¼ 1 e2 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 1.4 279.5 71.1 272.9 48.1 56.3 e 2021 þ1.27 þ0.11 þ0.56 0.04 1.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.993 1.000 99.6 353.6 181.4 174.8 eV 0.0012 0.069 1.73 1.11 0.19 1.11 e 2021 0.0017 0.0516 0.57 2.12 þ1.00 1.12 w1/h (N ¼ 17 e 2021, hr ¼ 39.8 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.48  0.13 (s ¼ 1.99  0.05) I: Hb ¼ 113.4 þ 1.53 Mv; Hmax ¼ 104.7 þ 0.71 Mv; He ¼ 99.4 þ 1.46 Mv (N ¼ 45) I: r w 0.23 g/cm3 (a1 ¼ 0.088 km, a2 ¼ 5.05/s) duncertain due to low N From c and s: w33,000 y; high dP/dlo versus i; Earth passing through core of stream (sU < su) e

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Brief history: Shower first reported by [1] from a compact group of 5 triangulated meteors by CAMS New Zealand in 2016, with a radiant at R.A. ¼ 277.8 , Decl. ¼ 71.7 and Vg ¼ 55.1 km/s around lo ¼ 1.1 . Strong activity reported in 2020 and 2021 [2,3]. The shower is of such short duration that meteor outbursts are likely. Some hints of that are listed above. No known past observations. Name and number assigned by [1]. References: [1] Jenniskens P. et al. (2018) PSS 154, 21e29; [2] Jenniskens P. (2021) eMeteorNews 6, 332e333; [3] Jenniskens P. (2021) CBET 4951, Ed.: D.W.E. Green, Cambridge: CBAT (March 28). March 26 (lo ¼ 5 )

828 TPG d 31 Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type comet shower, TJ ¼ þ0.61  0.37 Annual shower March 17eApril 4 (lo ¼ 356 e14 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 5.4 333.9 þ12.9 335.4 þ22.1 42.3 þ0.78 þ0.20 0.16 0.11 þ0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 29.2 0.247 0.991 49.2 59.3 5.4 64.4 eV 0.0138 0.0172 2.41 2.18 4.76 2.18 0.0029 þ0.0002 þ0.28 0.39 þ1.00 þ0.61 March 26 (lo ¼ 4.9 ) w0.2/h (N ¼ 35, hr ¼ 18.0 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.70  0.45 (s ¼ 2.08  0.16) Ib component has high He due to shallow entry angles: Ib: Hb ¼ 106.6  0.80 Mv; Hmax ¼ 99.0 þ 0.72 Mv; He ¼ 94.4 þ 0.92 Mv (N ¼ 22) Ib: r w 2.2 g/cm3 (a1 ¼ 0.055 km, a2 ¼ 2.67/s) duncertain due to low N From c and s: w8500 y; From model: w 27,000 y, precession to lower q e

Meteoroid density: Age: Source:

[see plate on p. 136]

Brief history: Shower first reported by [1] from a compact group of 4 CAMS-triangulated meteors from R.A. ¼ 334.4 , Decl. ¼ þ13.0 and Vg ¼ 42.3 km/s around lo ¼ 5.9 . No known past observations. Name and number assigned by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

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137

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April

139

April 7 (lo ¼ 18 )

752 AAC d April alpha Capricornids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1917-May-25.0 TDB

Long-period comet, TJ ¼ 0.97  0.26 Episodic shower 2014: April 7, 16:59 to 19:33 UTC: lo ¼ 17.60e17.71 April 5e11 (lo ¼ 15 e21 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 17.66 303.9 12.8 285.6 þ7.0 69.0 þ0.73 0.28 0.36 0.43 0.23 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 27.3 0.794 0.971 167.3 125.4 17.66 143.1 eV 0.011 0.059 1.18 1.13 0.032 1.13 e e e e 1.00 e e (N ¼ 15, hr ¼ 71.2 , m(Mv ¼ 0) ¼ 0.02 g) 2014: c w 1.6 (s w 1.54), meteors between þ2 and 3 magnitude I: Hb ¼ 113.0  1.15 Mv; Hmax ¼ 102.8 þ 1.74 Mv; He ¼ 99.8 þ 1.71 Mv (N ¼ 14) euncertain due to low N I: r w 0.81 g/cm3 (a1 ¼ 0.061 km, a2 ¼ 9.81/s) 1-rev. trail: w 250e4,000 y; Earth passing through core of stream (sU < su) C/1917 H1 (Schaumasse) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.764 1.000 158.7 119.1 10.8 129.9

Brief history: This appears to be an encounter with the 1-revolution dust trail of a longperiod comet. Fifteen meteors were triangulated by the SonotaCo network on April 7, 2014, during a 2h 34m period [1,2]. Radiant was at R.A. ¼ 304.5 , Decl. ¼ 12.7 and Vg ¼ 69.1 km/s around lo ¼ 17.65 . Shower was not seen in 2007e2013, nor in the more recent years 2015e2020. CAMS triangulated two possible shower meteors in 2021 during lo ¼ 17.45e51 , one of þ1.3 and one of þ2.0 magnitude. Dust trail modeling by [1] predicts returns on 2025 April 7 at 13 h UTC (Earth-trail miss distance Dr ¼ 0.0019 AU for 2014 assumed Dr ¼ 0.0 AU), April 7, 2032, at 12 h UTC (Dr ¼ þ0.0015 AU), 2039 April 7 at 05 h UTC (Dr ¼ 0.0008 AU), and 2049 April 7 at 17 h UTC (Dr ¼ 0.0010 AU). Possible source identified by R. Piffl [1], but correspondence is not good and the comet orbital period is longer than that of other long-period comets that have meteor showers. Name and number by [2]. References: [1] Kanamori T., Shimoda C., Inoue H., Masuzawa T., Sato M. (2014) JIMO 42, 222e226; [2] Sato M., Jenniskens P. (2014) CBET 3853, Ed.: D. W. E. Green, Cambridge: CBAT, issued April 12. April 12 (lo ¼ 22 ) Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

1055 TVL d 35 Vulpeculids Long-period comet, TJ ¼ þ0.17  0.37 Annual shower April 10e15 (lo ¼ 20 e25 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 22.0 321.8 þ26.5 313.1 þ39.1 50.3 þ0.94 þ0.12 þ0.04 0.23 0.12 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 39.5 0.570 0.986 88.1 97.7 22.0 119.8 eV 0.0213 0.0394 1.12 3.12 1.06 3.12 0.0060 0.0075 þ0.01 0.90 1.00 þ0.10 w0.1/h (N ¼ 20, hr ¼ 25.4 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.54  0.42 (s ¼ 2.01  0.19) I: Hb ¼ 110.3  1.37 Mv; Hmax ¼ 99.5 þ 0.58 Mv; He ¼ 94.9 þ 1.21 Mv (N ¼ 14) I: r w 1.6 g/cm3 (a1 ¼ 0.269 km, a2 ¼ 1.35/s) duncertain due to low N From c and s: w25,000 y; Earth passing through core of stream (sU < su) e

Brief history: First reported here. Possibly related to #1056.

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April

April 12 (lo ¼ 22 )

1056 AZC d April zeta Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.27  0.30 Annual shower April 10e14 (lo ¼ 20 e24 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 21.5 320.6 þ31.7 315.1 þ44.4 47.8 þ0.76 þ0.55 þ0.14 þ0.21 0.35 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 46.7 0.650 0.986 80.3 106.9 21.5 128.1 eV 0.0237 0.0355 0.90 3.15 1.10 3.15 þ0.0012 0.0100 0.59 0.10 1.00 þ0.90 w0.1/h (N ¼ 26, hr ¼ 27.4 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 2.62  0.34 (s ¼ 2.05  0.15) I: Hb ¼ 109.8  1.96 Mv; Hm ¼ 101.1 þ 0.25 Mv; He ¼ 96.8 þ 0.83 Mv (N ¼ 12) I: r w 0.92 g/cm3 (a1 ¼ 0.204 km, a2 ¼ 2.94/s) duncertain due to low N From c and s: w29,000 y; Earth passing through core of stream (sU < su) e

Brief history: First reported here. Possibly related to #1055. April 29 (lo ¼ 39 )

347 BPG d beta Pegasids

Meteoroid density:

Mellish-type shower, toroidal shower, TJ ¼ þ0.98  0.65 Annual shower April 15eMay 8 (lo ¼ 25 e48 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 34.7 352.3 þ28.1 329.4 þ28.8 43.1 þ0.80 þ0.33 0.11 0.02 þ0.12 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.36 0.321 0.955 63.2 67.2 34.7 101.3 0.0399 0.0539 5.56 5.70 6.40 5.70 0.0003 þ0.0013 þ0.33 þ0.00 þ1.00 þ1.00 w0.4/h (N ¼ 95, hr ¼ 22.8 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.86  0.23 (s ¼ 2.14  0.09) Component IIa has high end height, Ke > 82 due to shallow entry angle: IIa: Hb ¼ 104.0  0.09 Mv; Hmax ¼ 96.8 þ 1.18 Mv; He ¼ 91.7 þ 1.97 Mv (N ¼ 67) IIa: r w 0.93 g/cm3 (a1 ¼ 0.206 km, a2 ¼ 2.71/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

April 21eMay 9 (lo ¼ 31 e49 ) R.A. ( ) Decl. ( ) lo ( ) 39.3 351.8 þ30.5 þ1.00 þ0.37 a (AU) q (AU) e 2.74 0.327 0.884 0.0324 0.0569 0.0005 þ0.0006 N ¼ 258

Age: Source:

From c and s: w16,000 y e

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

l ( ) 329.6 þ0.08 i ( ) 61.2 5.80 0.15

b ( ) þ29.8 0.06 u ( ) 63.7 5.78 0.05

Vg (km/s) 46.7 0.02 U ( ) 39.3 4.29 þ1.00

P ( ) 103.0 5.78 þ0.95

eV

e R[M]

Brief history: Toroidal shower, showing smaller particles in shorter orbits. First reported from CMOR radar data by [1] with R.A. ¼ 350.5 , Decl. ¼ þ27.8 and Vg ¼ 41 km/s around lo ¼ 36 . Perhaps earlier recognized from Kharkiv Polytechnic Institute radar data by [2] (#5), with R.A. ¼ 343.5 , Decl. ¼ þ19.9 , Vg ¼ 38.4 km/s during April 15e22, and by [3]. However, because the average declination is 4 below the distribution found here, we will keep the #347. Confirmed from video observations by [4]. Number and name by [5]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81; [2] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [3] Sekanina Z. (1976) Icarus 27, 265e321; [4] Jenniskens P., et al. (2016) Icarus 266, 355e370; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp.

142

Allsky: Video and Radar

143

April

May 11 (lo ¼ 51 )

152 NOC d Northern Daytime omega Cetids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy:

Jupiter-family comet, Machholz Complex, TJ ¼ þ2.50  0.32 Annual shower May 1e23 (lo ¼ 40 e62 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 51.3 16.1 þ18.4 330.7 þ10.7 40.6 þ0.82 þ0.35 0.13 þ0.02 þ0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.44 0.0938 0.963 36.6 31.5 51.3 82.5 eV 1 0.0176 0.0136 6.19 3.23 7.90 3.23 ) 0.0007 þ0.0002 þ0.31 0.18 þ1.00 þ0.82 1 w0.8/h (N ¼ 81, hr ¼ 13.0 , m(Mv ¼ 0) ¼ 0.07 g) ) not including high b tail c ¼ 3.66  0.22 (s ¼ 2.41  0.07) II: Hb ¼ 99.9  0.01 Mv; Hmax ¼ 95.0 þ 0.98 Mv; He ¼ 89.8 þ 1.49 Mv (N ¼ 56) II: r w 3.5 g/cm3 (a1 ¼ 0.171 km, a2 ¼ 2.17/s) Mg0.87 Fe1.70 Na0.145 (N ¼ 1)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

April 9eMay 28 (lo ¼ 20 e67 ) R.A. ( ) Decl. ( ) lo ( ) 42.9 4.1 þ15.9 þ0.97 þ0.33 a (AU) q (AU) e 1.12 0.141 0.878 0.052 0.063 0.0012 þ0.0017 N ¼ 15,158

Age: Source: Orbital elements (J2000.0) Epoch 2003-Aug-22.0 TDB

From c: 13,000 y C/400 F1 a (AU) q (AU) N 0.210

e 1.000

l ( ) 329.2 þ0.00 i ( ) 29.1 7.07 þ0.10

b ( ) þ12.7 0.07 u ( ) 31.9 5.82 0.06

Vg (km/s) 32.3 þ0.12 U ( ) 42.9 12.52 þ1.00

i ( ) 32.0

u ( ) 47.0

U ( ) 38.0

P ( ) 75.1 5.82 þ0.94

e R[S]

duncertain P ( ) 85.0

Brief history: Shower first detected with Adelaide radar by [1] (shower 61.5.3) with R.A. ¼ 37.7 , Decl. ¼ þ20.0 , and Vg ¼ 36 km/s from observations during May 20e28, 1961 (lo ¼ 64 ) at the end of the activity interval. That interval was better understood from the Kharkiv Polytechnical Institute radar data by [2] (Table 3, No. 3), detecting 86 meteors from R.A. ¼ 356.7 , Decl. ¼ þ8 , and Vg ¼ 35.3 km/s during days of observation April 15eMay 26. Confirmed from Harvard meteor radar data by [3] having R.A. ¼ 2.3 , Decl. ¼ þ17.8 , and Vg ¼ 33 km/s. Recent CMOR detection by [4] has R.A. ¼ 9.0 , Decl. ¼ þ17.3 , and Vg ¼ 36.8 km/s centered on lo ¼ 45.5 . Name and number assigned by [5], who also proposed sungrazer C/2003 Q1 as being associated. C/400 F1 proposed here. References: [1] Nilsson C. S. (1964) AuJP 17, 205e256; [2] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [3] Sekanina Z. (1976) Icarus 27, 265e321; [4] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: C.U.P., 790 pp.

144

Allsky: Video and Radar

145

April

May 9 (lo ¼ 49 )

153 OCE d Southern Daytime omega Cetids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, Machholz Complex, TJ ¼ þ2.69  0.52 Annual shower April 18eMay 20 (lo ¼ 29 e60 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 49.4 22.7 5.3 330.4 13.2 38.9 þ0.93 þ0.42 þ0.04 þ0.03 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.04 0.115 0.943 39.3 214.0 229.4 82.8 0.0173 0.0308 4.86 4.01 8.51 4.01 0.0002 þ0.0004 þ0.18 0.01 þ1.00 þ1.01 w1/h (N ¼ 56, hr ¼ 19.3 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 3.93  0.74 (s ¼ 2.49  0.18) IIa: Hb ¼ 99.9  0.22 Mv; Hmax ¼ 90.4 þ 1.90 Mv; He ¼ 87.4 þ 1.84 Mv (N ¼ 56) IIa: r w 1.8 g/cm3 (a1 ¼ 0.131 km, a2 ¼ 2.82/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

March 29eMay 25 (lo ¼ 21 e64 ) R.A. ( ) Decl. ( ) lo ( ) 43.8 17.5 9.5 þ0.88 þ0.39 a (AU) q (AU) e 1.15 0.171 0.859 0.073 0.090 0.0007 þ0.0008 N ¼ 55,692

Age: Source: Orbital elements (J2000.0) Epoch 2005-Jan-03.0 TDB

From c: 17,000 y C/2004 V13 (SWAN) a (AU) q (AU) 33,640 0.181

FIG 5.2 Shower identifications.

e 1.000

l ( ) 330.4 þ0.02 i ( ) 30.1 12.4 þ0.09

b ( ) 15.1 þ0.02 u ( ) 215.5 9.0 0.06

Vg (km/s) 31.7 þ0.05 U ( ) 223.9 11.0 þ1.00

i ( ) 34.8

u ( ) 92.7

U ( ) 207.7

P ( ) 79.3 9.0 þ0.94

eV

e R[S]

duncertain P ( ) 79.6

Brief history: Strong shower first reported from early radar work at the Jodrell Bank Experimental Station (Lower Withington, Cheshire, England) by [1]. On four dates in May 1950, meteors radiated from an average R.A. ¼ 29.6 , Decl. ¼ 3.7 and Vg ¼ 36.7 km/s (lo ¼ 53e62 ) [2,3]. Confirmed by [4] in Harvard Radio Meteor Project (in Havana, Illinois) from 11 meteors with a radiant at R.A. ¼ 22.5 , Decl. ¼ 3.6 , and Vg ¼ 36.6 km/s. Called “omicron Cetids”. First more precise data from radar data by [5] with 970 meteor orbits having a radiant at R.A. ¼ 19.0 , Decl. ¼ 7.0 , Vg ¼ 36.5 km/s. More recent detection by [6]. Confirmed from low-light video observations here (Fig. 5.2). Name and number assigned by [7].

References: [1] Aspinall A., Hawkins G. S. (1951) MNRS 111, 20e21; [2] Almond M. (1951) MNRAS 111, 37e44; [3] Lovell A. C. B. (1954) Meteor Astronomy. Oxford: Clarendon Press, p. 463; [4] Sekanina Z. (1976) Icarus 27, 265e321; [5] Galligan D. P., Baggaley W. J. (2002) In: Dust in the Solar System and Other Planetary Systems. Ed.: S. F. Green, et al., New York: Pergamon, p. 48e60; [6] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [7] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp.

146

Allsky: Video and Radar

147

April

April 22 (lo ¼ 31 )

760 OCD d Octantids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ þ6.64  0.51 Annual shower, part of a ¼ 0.86 AU/i ¼ 60 group April 13eMay 1 (lo ¼ 23 e40 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 31.2 307.3 72.7 256.2 51.6 27.3 þ1.80 þ0.21 0.10 þ0.00 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) 0.79 0.546 0.314 57.9 158.7 211.2 0.0738 0.0588 4.25 9.80 3.29 0.0007 þ0.0008 0.09 0.04 þ1.00 0.97 0.797 0.174 65.1 112.7 206.0 N ¼ 2387 (m(Mv ¼ 0) ¼ 0.23 g) e r w 0.2e1.2 g/cm3 e e

eR

P ( ) 9.7 9.80 þ0.95 318.7

e R[S] e R[1]

Brief history: Because of the low speed and assumed high meteoroid density, the reported semi-major axis is likely close to the actual value. Shower first reported from SAAMER radar data by [1] from 257 meteors centered on lo ¼ 26 , at the beginning of the activity interval. At that time, the shower radiated from R.A. ¼ 294.1 , Decl. ¼ 77.4 with Vg ¼ 31.9 km/s (when l ¼ 252.9 , b ¼ 54.7 ). Part of a complex with #402, 405, 760, 763, 773, 775, 776, and 779 (a ¼ 0.79e0.94 AU, i ¼ 57e62 , smooth change of uei). Name and number assigned by [1]. References: [1] Pokorny P., et al. (2017) Icarus 290, 162e182. May 18 (lo ¼ 56 ) Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2003-Aug-22.0 TDB

1186 PSI d psi1 Piscids

[see plate on p. 144]

Jupiter-family comet, sunskirter, TJ ¼ þ3.28  0.30 Annual shower May 6e28 (lo ¼ 44 e67 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 55.5 16.4 þ21.8 327.4 þ13.2 39.3 þ0.88 þ0.32 0.09 0.03 þ0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.74 0.098 0.943 44.6 30.7 55.5 87.1 0.0124 0.0145 5.88 2.21 6.39 2.21 0.0013 þ0.0012 þ0.52 0.17 þ1.00 þ0.83 w0.5/h (N ¼ 47, hr ¼ 17.8 , m(Mv ¼ 0) ¼ 0.09 g) c ¼ 4.05  0.64 (s ¼ 2.52  0.16) II: Hb ¼ 97.3 þ 0.38 Mv; Hmax ¼ 93.4 þ 0.84 Mv; He ¼ 88.9 þ 1.34 Mv (N ¼ 36) II: low F ¼ 0.46, fragile II: r  2.3 g/cm3 (a1 ¼ 0.162 km, a2 ¼ 3.68/s), lower if fragile From c: 15,000 y 2013 JA36 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.665 0.138 0.948 42.5 31.5 56.3 87.8

Brief history: Shower first separated from #152 here. Source identified here.

eV

148

Allsky: Video and Radar

April

149

April 29 (lo ¼ 39 )

756 RPH d rho Phoenicids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Jupiter family comet, TJ ¼ þ1.98  0.55 Episodic shower 2020, 2022 April 23eMay 2 (lo ¼ 33 e42 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 39.1 15.5 50.0 307.5 50.4 43.0 þ0.81 þ0.57 þ0.19 0.14 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.99 0.766 0.740 76.9 296.5 219.2 155.3 eV 0.0361 0.0810 2.30 5.54 1.78 5.54 0.0003 þ0.0012 þ0.04 0.33 þ1.00 þ0.67 var. (N ¼ 38, hr ¼ 22.5 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 3.11  0.18 (s ¼ 2.23  0.06) II: Hb ¼ 98.1  0.44 Mv; Hmax ¼ 92.5 þ 0.65 Mv; He ¼ 88.3 þ 0.64 Mv (N ¼ 38) dlow N II: r w 2.7 g/cm3 (a1 ¼ 0.060 km, a2 ¼ 4.74/s) e e

Brief history: Unusual highly inclined short-period orbit. Shower first recognized from SAAMER radar data by [1] from R.A. ¼ 14.0 , Decl. ¼ 49.2 and Vg ¼ 43.0 km/s around lo ¼ 38 . Shower was unusually strong in 2020, when it was also detected by video [2]. Low numbers detected by video in 2021, but higher rates in 2022. Number and name assigned by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182; [2] Janches D., et al. (2020) CBET 4764, Ed.: D. W. E. Green, Cambridge: IAU CBAT, issued 22 April, 1pp. May 2 (lo ¼ 42 )

519 BAQ d beta Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.68  0.49 Annual shower April 28eMay 12 (lo ¼ 38 e62 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 41.8 319.6 1.4 280.2 þ13.8 68.3 þ0.79 þ0.22 0.16 0.06 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 12.0 0.919 0.924 156.0 144.9 41.8 186.4 eV 0.0113 0.103 1.24 3.25 5.63 3.25 þ0.0026 0.0004 þ0.12 þ0.54 þ1.00 þ1.54 w0.8/h (N ¼ 339, hr ¼ 36.8 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.42  0.15 (s ¼ 2.33  0.05) I: Hb ¼ 116.1  1.00 Mv; Hmax ¼ 105.2 þ 1.71 Mv; He ¼ 96.2 þ 2.55 Mv (N ¼ 97) III: Hb ¼ 100.4 þ 0.22 Mv; Hmax ¼ 96.0 þ 1.24 Mv; He ¼ 92.0 þ 0.90 Mv (N ¼ 145) I: low F ¼ 0.52, fragile meteoroids I: r  0.52 g/cm3 (a1 ¼ 0.070 km, a2 ¼ 4.49/s), lower if fragile III: r w 4.5 g/cm3 (a1 ¼ 0.039 km, a2 ¼ 9.79/s) dNa free III: Mg1.37 Fe0.56 Na0.005 (N ¼ 1), Na depleted From c and s: w69,000 y; From model: w40,000 y e

Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source:

[see plate on p. 150]

Brief history: Shower first reported from Croatian Meteor Network video observations by [1] based on 20 triangulated meteors over period April 23 to May 20, from R.A. ¼ 323.0 , Decl. ¼ 0.4 and Vg ¼ 68.4 km/s around lo ¼ 46.3 . Confirmed by [2]. Name and number assigned by [1]. References: [1] Andreic Z., et al. (2013) JIMO 41, 103e108; [2] Jenniskens P., et al. (2016) Icarus 266, 355e370.

150

Allsky: Video and Radar

April

151

April 29 (lo ¼ 39 )

343 HVI d h Virginids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Aug-09.0 TDB

Jupiter-family comet, TJ ¼ þ2.74  0.20 Episodic shower 2008e2009, 2014e2015, 2019e2020 April 21eMay 7 (lo ¼ 30 e47 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 38.8 203.0 10.9 166.5 1.2 18.8 þ0.29 0.25 0.65 0.13 0.24 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.00 0.752 0.750 0.70 65.9 218.7 284.5 eV 0.0104 0.0314 0.347 1.37 2.51 1.37 þ0.0076 0.0024 þ0.05 1.05 þ1.00 0.01 var. (N ¼ 697, hr ¼ 45.5 , m(Mv ¼ 0) ¼ 0.43 g) c ¼ 2.31  0.03 (s ¼ 1.91  0.02) Ib: Hb ¼ 96.1  1.05 Mv; Hmax ¼ 86.9 þ 0.61 Mv; He ¼ 82.2 þ 1.19 Mv (N ¼ 470) Ib: r w 1.42  0.21 g/cm3 (a1 ¼ 0.073 km, a2 ¼ 2.90/s) e 2009 HS44 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.57 0.767 0.702 2.44 73.3 209.1 282.4

Brief history: In the 19th century, [7] placed the “a-Virginids” at R.A. ¼ 205.4 , Decl. ¼ 8.7 (his shower #158), said to supply “many large slow-moving meteors in April.” Over the years, the Virginid activity centers remained poorly defined. That changed with the recent video orbit surveys. Shower #343 was first reported from 2007 to 2008 SonotaCo video observations by [1,6] from R.A. ¼ 204.2 , Decl. ¼ 11.6 and Vg ¼ 18.7 km/s around lo ¼ 39 . [2] identified the shower from single-station Video Meteor Network data, but that identification is in doubt because the radiant was off at R.A. ¼ 214.1 , Decl. ¼ 11.4 during  lo ¼ 32e35 . Confirmed from 11 triangulated FIG 5.3 ZHR profile. orbits by [3] obtained during April 27 and May 2, 2012. Radiant at R.A. ¼ 206.4 , Decl. ¼ 12.0 during lo ¼ 40.2 [4], in good agreement with [1]. Here, we find peak ZHR w 1.6/h in outburst years, with weak activity in non-outburst years (Fig. 5.3). The yearly count since 2007: 0, 14, 11, 0, 0, 4, 13, 27, 36, 2, 2, 2, 66, 483, 53, 19 (with gradually increasing number of cameras in the networks). Activity is centered on 2008.77, 2014.63 and 2020.31 suggesting a periodicity of w5.77 y. The meteoroid orbits appear to be in resonance with Jupiter, because of episodic activity and a narrow shower activity profile [8]. Hence, the meteoroids may be in the 2:1 mean-motion resonance, with an orbital period of w5.93 y (a ¼ 3.28 AU). Recently, 2001 SZ269 was identified as a possible parent body by [5], but this object is not as good a match as 2009 HS44 (a ¼ 2.57 AU) identified here. Even this may be an asteroidal interloper. 2009 HS44 is a small object with an absolute magnitude of only H ¼ 26.5 and the parent body is also likely in or near the 2:1 resonance. Name and number assigned by [1]. References: [1] Kanamori T. (2009) JIMO 37, 55e62; [2] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [3] Jenniskens P., et al. (2016) Icarus 266, 355e370; [4] Roggemans P., Johannink C., Sekiguchi T. (2020) eMeteorNews 4, 233e244; [5] Sergienko M. V., et al. (2021) Journal of Physics: Conf. Ser. 2103, id.012037, 7pp; [6] Kanamori T. (2009) CBET 1771. Ed.: D. W. E. Green. Cambridge: CBAT, 1pp; [7] Denning W. F. (1899) Mem. R.A.S. 53, 201e293; [8] Koseki M. (2020) eMeteorNews 5, 245e251.

152

Allsky: Video and Radar

April

153

May 2 (lo ¼ 42 )

658 EDR d epsilon Draconids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.73  0.15 Episodic shower 2008e2009, 2013e2015, 2019e2020, . April 23eMay 15 (lo ¼ 32 e55 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 41.5 323.9 þ73.3 3.3 þ72.4 24.4 þ1.86 þ0.34 þ0.24 0.28 0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.04 0.958 0.691 37.9 151.8 41.5 192.7 eV 0.0117 0.109 3.36 3.48 4.92 3.48 0.0015 þ0.0005 0.30 0.48 þ1.00 þ0.52 w0.3/h (N ¼ 305, hr ¼ 43.4 , m(Mv ¼ 0) ¼ 0.24 g) c ¼ 2.70  0.20 (s ¼ 2.08  0.08) I: Hb ¼ 101.7  2.22 Mv; Hmax ¼ 93.7  1.33 Mv; He ¼ 88.7  0.79 Mv (N ¼ 40) II: Hb ¼ 93.0  1.78 Mv; Hmax ¼ 83.7 þ 0.73 Mv; He ¼ 78.5 þ 1.54 Mv (N ¼ 131) I: r w 2.0 g/cm3 (a1 ¼ 0.106 km, a2 ¼ 3.39/s) II: r w 2.5 g/cm3 (a1 ¼ 0.074 km, a2 ¼ 6.43/s) dpossibly Na poor e e

Meteoroid density: Age: Source:

Brief history: Shower first reported from CAMS video observations by [1]. Name and number assigned by [1]. Possibly related activity or a second shower NE of the main concentration with R.A. ¼ 309.9 , Decl. ¼ þ78.2 , Vg ¼ 23.6 km/s over lo ¼ 36e54 (l ¼ 377.5, b ¼ þ73.8). Sky from HAPLAR data shown in Fig. 5.4. References: [1] Jenniskens P., et al. (2016) Icarus 266, 355e370.

FIG 5.4

HAPLA radar detection of the eta Aquariids (#31).

154

Allsky: Video and Radar

155

May

May 9 (lo ¼ 49 )

763 UPA d upsilon Pavonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median (763): Number observed: Magn. distribution index: Meteoroid density: Source:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ 6.51  0.58 Annual shower, part of a ¼ 0.86 AU, i ¼ 60 group May 2e18 (lo ¼ 42 e58 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 49.8 311.9 67.0 242.9 47.1 29.3 þ1.26 þ0.37 0.13 þ0.17 0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) 0.83 0.494 0.420 60.6 141.5 229.8 0.1010 0.0710 8.20 12.50 3.60 0.0065 þ0.0059 0.28 þ0.60 þ1.00 0.86 0.470 0.452 63.5 135.8 234.0 N ¼ 7620 (m(Mv ¼ 0) ¼ 0.16 g) c ¼ 4.41  0.18 (s ¼ 2.61  0.04) II: r w 1.5 g/cm3 (a1 ¼ 0.061 km, a2 ¼ 5.07/s). e

eR

P ( ) 11.5 12.50 þ1.60 9.8

e R[S] e R[1] eV eV

Brief history: [1] first reported two showers from SAAMER radar data with a very similar radiant: #762 at R.A. ¼ 315.5 and Decl. ¼ 69.9 around lo ¼ 46 and #763 at R.A. ¼ 309.0 , Decl. ¼ 65.3 and Vg ¼ 31.0 km/s peaking on lo ¼ 54 . Both had Vg ¼ 31.0 km/s. I find instead that during this time period (lo ¼ 40 e59 ), there is just one shower, best matched by number 763. There is, however, also a second shower with slightly higher entry speed, partially overlapping the activity region, here assigned the number 762. Tentative identification in CAMS video data (N ¼ 80) here. Part of a group that include #402, 405, 760, 763, 773, 777, and 779 (a ¼ 0.79e0.94 AU, i ¼ 57e62 , smooth change of uei). Names assigned by [1]. References: [1] Pokorny P., et al. (2017) Icarus 290, 162e182. May 9 (lo ¼ 49 )

762 OPA d omicron Pavonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median (762): Number observed: Meteoroid density: Source:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ 3.34  0.71 Annual shower April 30eMay 16 (lo ¼ 40 e56 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 49.1 270.3 69.6 227.6 46.8 40.2 0.01 þ0.02 0.08 0.06 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) 1.82 0.659 0.650 72.3 88.9 229.4 0.0540 0.114 4.89 8.41 4.37 þ0.0015 þ0.0025 0.02 0.20 þ1.00 0.88 0.604 0.312 64.5 133.6 226.0 N ¼ 1702 (m(Mv ¼ 0) ¼ 0.07 g) r w 0.2e1.2 g/cm3 e

eR

P ( ) 314.4 8.41 þ0.80 0.4

e R[S] e R[1]

Brief history: [1] first reported two showers from SAAMER radar data with a very similar radiant: #762 at R.A. ¼ 315.5 and Decl. ¼ 69.9 with Vg ¼ 31.0 km/s around lo ¼ 46 and #763 at R.A. ¼ 309.0 , Decl. ¼ 65.3 and Vg ¼ 31.0 km/s peaking on lo ¼ 54 . Both had Vg ¼ 31.0 km/s. Here it is found instead that during this time period (lo ¼ 40e59 ), there is just one shower, best matched by the original data for number 763. There is, however, also a second shower with slightly higher entry speed, partially overlapping the activity region, here assigned the number 762. Tentative detection in CAMS video data here. Name assigned by [1]. References: [1] Pokorny P., et al. (2017) Icarus 290, 162e182.

156

Allsky: Video and Radar

157

May

May 21 (lo ¼ 60 )

351 DTR d Daytime Triangulids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, TJ ¼ þ2.02  0.37 Annual shower April 19eJune 10 (lo ¼ 29 e80 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 59.9 43.0 þ36.7 352.5 þ19.9 29.8 þ0.98 0.09 0.25 0.35 þ0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 4.39 0.475 0.893 21.7 82.5 59.9 138.8 0.0704 0.0462 3.39 8.76 12.07 8.76 0.0061 þ0.0004 0.12 0.74 þ1.00 þ0.26 w1/h (N ¼ 82, hr ¼ 10.5 , m(Mv ¼ 0) ¼ 0.15 g) c ¼ 3.30  0.18 (s ¼ 2.32  0.06) Ib: Hb ¼ 100.9  0.73 Mv; Hmax ¼ 94.1 þ 0.38 Mv; He ¼ 89.8 þ 1.08 Mv (N ¼ 58) Ib: r w 2.8 g/cm3 (a1 ¼ 0.385 km, a2 ¼ 1.15/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

May 5eJune 2 (lo ¼ 45 e71 ) lo ( ) R.A. ( ) Decl. ( ) 58.7 44.2 þ36.3 þ1.01 þ0.20 a (AU) q (AU) e 3.05 0.470 0.843 0.0374 0.0396 0.0023 þ0.0013 4.24 0.561 0.868 N ¼ 78

l ( ) 353.5 0.12 i ( ) 19.5 2.14 þ0.04 16.2

b ( ) þ18.6 0.05 u ( ) 80.4 5.67 0.24 92.6

Vg (km/s) 28.6 þ0.08 U ( ) 58.7 5.92 þ1.00 46.0

P ( ) 138.7 5.67 þ0.76 138.6

eV

e R[M] e R[1]

Brief history: The point cloud of a video-detected shower overlaps with shower #351 “Daytime Triangulids” reported from CMOR observations by [1] based on 519 triangulated meteors from a radiant at R.A. ¼ 35.9 , Decl. ¼ þ34.1 and Vg ¼ 26.2 km/s centered on lo ¼ 46.0 (lo ¼ 44.0e46.0 ), but also with the nearly identical, but slightly later, shower #354 “Daytime delta Triangulids” from radiant at R.A. ¼ 35.3 , Decl. ¼ þ33.7 and Vg ¼ 28.4 km/s centered on lo ¼ 53.0 (lo ¼ 52.0e54.0 ). In fact, the video-detected shower covers the activity period of both showers and is of much longer duration. The radiant is elongated in ecliptic latitude and the center of the stream moves toward the ecliptic plane with increasing solar longitude (Fig. 5.5). The video-detected shower is weakly detected by the MAARSY radar (reported here) and both are centered on a later solar longitude. Name and number by [1], adopting the lowest number. References: [1] Brown P., et al. (2010) Icarus 207, 66e81.

FIG 5.5

Radiant drift (• ¼ CAMS, x ¼ SAAMER).

158

Allsky: Video and Radar

May

159

May 24 (lo ¼ 63 )

451 CAM d Camelopardalids

Dynamic type: Shower type: Year of outbursts:

Jupiter-family comet, TJ ¼ 2.99  0.21 Episodic shower 2011: [13] 2014: lo ¼ 62.91 , ZHR ¼ 13e26/h, FWHM ¼ 6.0 h [6,8] d1868 to 1919 trails 2019: lo ¼ 62.49e62.66 (N ¼ 3) [15] 2022: lo ¼ 63.71 , ZHR w 14 h, FWHM ¼ 4.5 h e1903/1909 dust trails [14] May 21e28 (lo ¼ 60 e67 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 62.5 121.4 þ78.9 37.3 þ56.6 16.2 þ0.40 0.09 0.80 0.14 0.37 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.61 0.966 0.629 20.6 151.8 62.8 214.6 eV 0.0031 0.0782 1.75 1.32 1.04 1.32 0.0008 0.0324 0.37 0.65 þ1.00 þ0.34 N ¼ 40 (hr ¼ 44.5 , m(Mv ¼ 0) ¼ 0.57 g) c ¼ 2.37  0.17 (s ¼ 1.94  0.08); c ¼ 3.7  0.5 [6]; c ¼ 2.93  0.11 [8] Ib: Hb ¼ 93.0  1.07 Mv; Hmax ¼ 85.8 þ 0.01 Mv; He ¼ 78.4 þ 1.48 Mv (N ¼ 21) III: Hb ¼ 82.8  0.28 Mv; Hmax ¼ 80.8  0.13 Mv; He ¼ 78.9  0.12 Mv (N ¼ 9) Ib: low F ¼ 0.49, fragile meteoroids Ib: r  1.8 g/cm3 (a1 ¼ 0.070 km, a2 ¼ 2.92/s), fragile: low a2 III: r w 4.9 g/cm3 (a1 ¼ 0.026 km, a2 ¼ 7.47/s) dpossibly Na poor/free 0.8e9.0  104 dyn/cm2 [7], Abundant fragmentation of bright meteors [6], CMOR-detected small meteoroids have high tensile strength [12] Slightly depleted in Na and Fe, about Mg1.00 Fe0.68 Na0.46 [7] 2011: 1763, 1768 returns [12] 2014: trails from 1798 to 1979, mostly 1903, 1909 returns [4] 2022: 1903,1909 returns [14] 209P/LINEAR a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.93 0.903 0.692 20.6 152.1 63.6 215.7

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Strength: Spectroscopy: Age:

Source: Orbital elements (J2000.0) Epoch 2012-Jan-21.0 TDB

Brief history: Following discovery of 209P/LINEAR (¼ 2004 CB), a 2014 meteor outburst was predicted by [1]. Shower first detected in a D-criterion survey of video data by [2] from R.A. ¼ 172.6 , Decl. ¼ þ83.7 and Vg ¼ 14.7 km/s around lo ¼ 39.1 . Confirmed by [3]. More detailed outburst prediction by [4]. Comet observations by [5]. Observations of Camelopardalids in airborne observing campaign by [6]. Bright meteors had strong fragment wake. Spectra by [7]. Mass distribution index by [8]. Predicted outburst in 2019 by [9]; Observations of 2019 outburst by [10,11]. Observations of 2022 outburst by [16,17]. Observations of the comet during the 2014 return by [13]. Name and number by [1]. References: [1] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, pp. 129 and 689; [2] Rudawska R., Jenniskens P. (2014) In: Meteoroids 2013. Eds.: T. J. Jopek et al., Poznan: A. M. Univ., p. 217e224; [3] Kornos L. et al. (2014) Meteoroids 2013. Eds.: T. J. Jopek et al., Poznan: A. M. Univ., p. 225e233; [4] Ye Q., Wiegert P. (2014) MNRAS 437, 3283e3287; [5] Ishiguro M., Kuroda D., Hanayama H., et al. (2015) ApJ Lett. 798, L34eL40; [6] Jenniskens P. (2014) JIMO 42, 98e105; [7] Madiedo J. M., Trigo-Rodríguez J. M., Zamorano J., et al. (2014) MNRAS 445, 3309e3314; [8] Campbell-Brown M. D., Blaauw R., Kingery A. (2016) Icarus 277, 141e153; [9] Maslov M. (2017) eMeteorNews 2, 96e96; [10] Vida D., Eschman P. (2019) eMeteorNews 5, 30e32; [11] Martin P. (2019) eMeteorNews 4, 244e245; [12] Ye Q.-Z., et al. (2016) Icarus 264, 48e61; [13] Ishiguro M., et al. (2014) ApJ Lett. 798, L34eL40; [14] Sugimoto H., Ogawa H. (2022) eMeteorNews 4, 242e243; [15] Vida D., Eschman P. (2020) eMeteorNews 5, 30e31; [16] Segon D., Vida D., Roggemans P. (2022) eMeteorNews 7, 236e241; [17] Sugimoto H., Ogawa H. (2022) eMeteorNews 242e243.

160

Allsky: Video and Radar

May

161

162

Allsky: Video and Radar

June

163

June 11 (lo ¼ 81 )

680 JEA d June epsilon Arietids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter family comet, Machholz Complex, TJ ¼ þ2.35  1.11 Annual shower June 2e20 (lo ¼ 72 e90 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 80.8 46.1 þ26.9 330.3 þ9.1 41.6 þ0.68 þ0.23 0.34 þ0.05 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.50 0.071 0.969 36.9 27.5 80.7 109.2 eV 0.0218 0.0170 7.26 3.52 3.67 3.52 0.0034 þ0.0009 þ0.61 0.46 þ1.00 þ0.54 w2/h (N ¼ 127, hr ¼ 13.9 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 3.15  0.14 (s ¼ 2.25  0.05) Component II has high end height, Ke > 82: II: Hb ¼ 99.4 þ 0.00 Mv; Hmax ¼ 95.1 þ 0.86 Mv; He ¼ 90.7 þ 1.08 Mv (N ¼ 107) II: low F ¼ 0.49, fragile II: r  1.7 g/cm3 (a1 ¼ 0.494 km, a2 ¼ 1.76/s) From c: 8000 y 342P/SOHO duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.04 0.053 0.983 13.3 58.7 43.4 102.1

Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2016-Jul-31.0 TDB

Brief history: Radiant is just north of that of the strong #171 ARI (Daytime Arietids). Appears to have been first resolved by CAMS video observations [1] from R.A. ¼ 46.7 , Decl. ¼ þ27.1 and Vg ¼ 39.1 km/s around lo ¼ 85.0 . Likely related to Marsden group of sunskirter comets linked to Daytime Arietids. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409. March 25 (lo ¼ 5 )

690 MEP e March epsilon Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age:

Long-period comet, TJ ¼ -0.01  0.41 Annual shower March 21 e 28 (lo ¼ 1 e 8 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 4.9 324.0 þ6.1 324.3 þ19.7 50.0 þ0.83 þ0.15 0.12 0.14 þ0.20 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.160 1.003 82.0 46.4 4.9 50.9 eV 0.0175 0.0119 1.64 3.10 1.90 3.10 0.0014 þ0.0016 þ0.71 0.15 þ1.00 þ0.85 w0.2 /h (N ¼ 11, hr ¼ 17.1 , m(Mv¼0) ¼ 0.04 g) c ¼ 2.35  0.39 (s ¼ 1.92  0.17) I: Hb ¼ 110.0  1.05 Mv; Hmax ¼ 99.7 þ 1.42 Mv; He ¼ 96.7 þ 1.12 Mv (N ¼ 11) euncertain due to low N I: r w 1.6 g/cm3 (a1 ¼ 0.433 km, a2 ¼ 1.47 /s) From c and s: w6,000 y

Brief history: First reported here. Name and number here.

[see pates on p. 46]

164

Allsky: Video and Radar

June

165

June 21 (lo ¼ 90 )

172 ZPE d Daytime zeta Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter family comet, TJ ¼ þ3.30  0.33 Annual shower June 8eJuly 11 (lo ¼ 77 e109 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 90.3 76.1 þ27.0 345.4 þ4.7 28.1 þ0.88 þ0.12 0.20 0.01 þ0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.91 0.330 0.824 5.5 58.7 90.4 154.4 eV 0.0625 0.0477 1.41 8.31 9.64 8.31 0.0006 0.0016 0.03 þ0.02 þ1.00 þ1.02 N ¼ 53 (hr ¼ 5.8 , m(Mv ¼ 0) ¼ 0.18 g) ZHR w 3/h; 14  2/h [13] c ¼ 3.13  0.14 (s ¼ 2.24  0.05) Component IIa has high end height, Ke > 82 (due to small entry angle?): IIa: Hb ¼ 96.3 þ 0.50 Mv; Hmax ¼ 92.3 þ 0.96 Mv; He ¼ 88.3 þ 1.12 Mv (N ¼ 34) IIa: Low F ¼ 0.50, fragile IIa: r  6 g/cm3 (a1 ¼ 0.237 km, a2 ¼ 0.85/s), lower if fragile e uncertain, low N

Lightcurve shape: Meteoroid density:

Period of activity: May 31eJune 27 (lo ¼ 70 e97 ) Shower radiant/speed lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) Median (geocentric): 78.8 63.0 þ25.5 347.0 þ4.1 25.7 Drift per day (d/dlo): þ1.03 þ0.16 0.05 0.00 þ0.06 Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Median: 1.59 0.358 0.776 5.03 60.3 78.8 140.3 Dispersion (±s): 0.0716 0.0485 1.31 9.76 5.40 9.76 Drift (d/dlo): 0.0022 þ0.0011 þ0.02 0.25 þ1.00 þ0.75 Median: 2.33 0.350 0.850 8.00 61.0 77.0 138.0 Number observed: N ¼ 1009 Magn. distribution index: s ¼ 2.19  0.12 (peak) [5]; s ¼ 1.81  0.05 (ave), s ¼ 1.71  0.05 (peak) [12]

e R[S] e R[2]

4500 y [8]; w2000 y [11]; if from 2P (trapped in 7:2 mean motion resonance for some time): >16,000 y [14] Source: 2P/Encke Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Epoch 2015-Aug-04.0 TDB 2.22 0.336 0.848 11.8 186.5 334.6 161.1 Age:

Brief history: Daytime meteor shower activity from Aries and Perseus (20e40 per hour) was discovered in 1947 with radar equipment at Jodrell Bank, UK [1]. The approximate radiant was at R.A. ¼ 52e62 , Decl. ¼ þ15 . In 1948, showers Daytime Arietids (#171) and Daytime zeta Perseids (#172) were separated [2]. Discovery led to publication of [3]. Confirmation came from Kharkiv Polytechnic Institute radar by [4] with R.A. ¼ 52, Decl. ¼ þ23. Magnitude distribution index from Ondrejov Radar by [5]. CMOR data by [12]. Confirmation from video observations by [6]. Link with comet Encke by [8]. Early models by [9,10]. Model by [11] has #172 resulting from 2P ejecta, with [14] match activity if 2P resided several thousand years in 7:2 mean-motion resonance. Name by [1]. Number by [7]. References: [1] Clegg J. A., Hughes V. A., Lovell A. C. B. (1947) MNRAS 107, 369e378; [2] Aspinall A., Clegg J. A., Lovell A. C. B. (1949) MNRAS 109, 352e358; [3] Lovell A.C. B. (1954) Meteor Astronomy. Oxford: Clarendon Press, 463 pp; [4] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 11, 183e199; [5] Porubcan V., et al. (2007) Contr. Astron. Obs. Skalnaté Pleso 37, 31e48; [6] Jenniskens P., et al. (2016) Icarus 266, 355e370; [7] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [8] Whipple F. L. (1940) Proceedings of the American Phil. Soc. 83, 711e745; [9] Makhmudov N. (1986) Akademiia Nauk Tadzhikskoi SSR, Doklady 29, 84e87; [10] Whipple F. L., Hamid S. E. (1952) Helwan Obs. Bull. No. 41, 1e30; [11] Tomko D., Neslusan L. (2019) AA 623, A13eA37; [12] Dewsnap R. L., Campbell-Brown M. (2021) MNRAS 507, 4521e4529; [13] Egal A. (2022) MNRAS 512, 2318e2336; [14] Egal A., et al. (2021) MNRAS 507, 2568e2591.

166

Allsky: Video and Radar

167

June

July 7 (lo ¼ 105 )

173 BTA d Daytime beta Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter family comet, TJ ¼ þ2.96  0.43 Annual shower June 7eJuly 22 (lo ¼ 76 e120 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 105.4 90.1 þ21.2 342.2 2.2 32.7 þ0.81 þ0.06 0.24 þ0.02 þ0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.31 0.230 0.910 3.34 230.1 285.3 155.2 eV 0.0619 0.0405 1.45 8.37 10.4 8.37 0.0039 þ0.0003 þ0.01 0.55 þ1.00 þ0.45 N ¼ 29 (hr ¼ 5.5 , m(Mv ¼ 0) ¼ 0.13 g) w1/h; 9  2/h [14] c ¼ 2.96  0.73 (s ¼ 2.18  0.23) Ib: Hb ¼ 101.9 þ 0.12 Mv; Hmax ¼ 93.9 þ 1.89 Mv; He ¼ 90.4 þ 2.41 Mv (N ¼ 24) duncertain due to low N Ib: r w 4.1 g/cm3 (a1 ¼ 2.14 km, a2 ¼ 0.33/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index:

June 3eJuly 18 (lo ¼ 73 e116 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) 94.0 76.3 þ19.2 349.5 3.5 þ1.03 þ0.13 0.03 þ0.03 a (AU) q (AU) e i ( ) u ( ) 1.70 0.403 0.768 3.11 245.9 0.082 0.072 1.66 10.1 0.0008 þ0.0008 0.02 þ0.06 2.20 0.340 0.845 6.00 224.0 N ¼ 2480 s ¼ 2.19  0.11 (peak) [5], s ¼ 1.87  0.05 (ave) [12]

Age:

4500 [10]; split from Encke: w5200 [13]; current activity w2000 [11]; If from 2P alone (trapped in 7:2 MMR for some time): 7e14,000 y [13] 2004 TG10 a (AU) q (AU) e i ( ) u ( ) U ( ) 2.23 0.308 0.862 4.0 299.3 223. 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6

Source: Orbital elements (J2000.0) Epoch 2017-Nov-06.0 TDB Source: Epoch 2015-Aug-04.0 TDB

Vg (km/s) 25.7 þ0.05 U ( ) 268.1 6.7 þ1.00 278.1

P ( ) 154.2 11.9 þ0.94 142.1

e R[S] e R[4]

P ( ) 162.5 161.1

Brief history: Predicted as a daytime twin shower of nighttime Taurids by [1]. Radar at Jodrell Bank, UK, detected activity of Taurids from R.A. ¼ 79e85 , Decl. ¼ þ20e30 in 1947 [2]. Link with nighttime Taurids recognized by [3]. Details on the discovery in [4]. In 1950, date of peak activity determined by [5]. First orbit determined by [3]; Magnitude distribution index from Ondrejov Radar by [6]. CMOR by [12]. First model and link with comet Encke by [8,9]. Link with 2004 TG10 by [10]. Model by [13] puts Encke and 2004 TG10 breakup at 3200 BCE. Model by [11] has #173 identified with specific filaments from 2P ejecta, with [13] matching activity if 2P resides several thousand years in 7:2 mean-motion resonance. Name by [1]. Number by [7]. References: [1] Whipple F. L. (1940) Proc. Am. Phil. Soc. 83, 711e745; [2] Clegg J. A., et al. (1947) MNRAS 107, 374e375; [3] Almond M. (1951) MNRAS 111, 37e44; [4] Lovell A. C. B. (1954) Meteor Astronomy. Oxford: Clarendon Press, 463 pp; [5] Aspinall A., Hawkins G. S. (1951) MNRAS 111, 18e25; [6] Porubcan V., et al. (2007) Contr. Astron. Obs. Skalnaté Pleso 37, 31e48; [7] Jenniskens P. (2006) Meteor Showers and their Parent Comets, CUP, 790 pp; [8] Whipple F. L., Hamid S. E. (1952) Helwan Obs. Bull. No. 41, 1; [9] Makhmudov N. (1986) Akademiia Nauk Tadzhikskoi SSR, Doklady 29, 84e87; [10] Ye Q.-Z. (2018) PSS 164, 7e12; [11] Tomko D., Neslusan L. (2019) AA 623, A13eA37; [12] Dewsnap R. L., CampbellBrown M. (2021) MNRAS 507, 4521e4529; [13] Egal A., et al. (2021) MNRAS 507, 2568e2591; [14] Egal A. (2022) MNRAS 512, 2318e2336.

168

Allsky: Video and Radar

June

169

June 15 (lo [ 85 )

69 SSG d Southern mu Sagittariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.28  0.21 Annual shower May 25eJuly 10 (lo ¼ 64 e110 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 85.0 272.5 29.6 187.2 6.2 25.9 þ0.71 0.03 0.38 0.04 0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.14 0.446 0.767 6.21 105.6 265.0 10.8 eV 0.0301 0.0589 1.10 2.59 7.13 2.59 þ0.0065 0.0009 0.04 0.80 þ1.00 þ0.20 N ¼ 2528 (hr ¼ 44.0 , m(Mv ¼ 0) ¼ 0.23 g) w0.5/h; ZHR ¼ 2.4  0.5, B ¼ 0.037  0.005 [11] c ¼ 3.06  0.10 (s ¼ 2.22  0.03); 2.9 [11] Ib component has high He: Ib: Hb ¼ 98.1  0.87 Mv; Hmax ¼ 87.9 þ 0.90 Mv; He ¼ 83.4 þ 1.32 Mv (N ¼ 2248) IIb: Hb ¼ 88.7  0.64 Mv; Hmax ¼ 83.9 þ 0.10 Mv; He ¼ 79.8 þ 0.48 Mv (N ¼ 158) Ib: r w 0.93  0.12 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 4.98/s) IIb: r w 3.0  0.7 g/cm3 (a1 ¼ 0.072 km, a2 ¼ 6.64/s) dpossibly Na poor e 2020 BC6 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.86 0.540 0.710 6.30 98.4 272.5 10.9

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

Brief history: Shower in anthelion source. q strong function of lo. Shower is strong and compact for TJ > 3. At TJ < 3 may be an underlying broader shower (#1132, not shown). Known by visual observers as “gamma Sagittarids” [1]. First identified from Adelaide radar detected meteors. [2] had “Sagittarids” peaking on June 11 at R.A. ¼ 304 , Decl. ¼ 34 . [3] reported (shower 61.6.9) with radiant at R.A. ¼ 268.0 , Decl. ¼ 27.7 and Vg ¼ 23.3 km/s. Confirmed by [4] (shower 6.01) and in Harvard Radio Project meteor data by [5]. The stream has a steep magnitude distribution index, being rich in small particles. Only tentatively identified from two photographed meteors about 11 further East by [6]: HV 7944 (lo ¼ 103.9 , R.A. ¼ 272.1 , FIG 5.6 ZHR profile.  Decl. ¼ 11.0 , Vg ¼ 19.3 km/s) and HV8017 (112.4 , 281.0 , 27.6 , 18.7 km/s). Also identified in [7,8] with slightly lower mean velocity and i ¼ 2.6 . Video confirmation by [9]. Activity curve shown in Fig. 5.6. Possible parent body 2020 BC6 identified here. Number by [6], name by [10]. References: [1] McIntosh R. A. (1935) MNRAS 95, 709e718; [2] Weiss A. A. (1960) AuJPh 13, 522e531; [3] Nilsson C. S. (1964) AuJPI 17, 226e229; [4] Gatrell G., Elford W. G. (1975) AuJPh 28, 591e620; [5] Sekanina Z. (1976) Icarus 27, 265e321; [6] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [7] Porubcan V., Gavajdová M. (1995) PSS 42, 151e153; [8] Gavajdová M. (1995) EMP 68, 289e292; [9] Jenniskens P., et al. (2016) Icarus 266, 355e370; [10] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [11] Jenniskens P. (1994) AA 287, 990e1013.

170

Allsky: Video and Radar

June

171

June 22 (lo ¼ 92 )

681 OAQ d omicron Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.27  0.51 Annual shower June 10eJuly 17 (lo ¼ 80 e107 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 91.9 328.8 4.8 238.1 þ7.1 62.7 þ0.77 þ0.19 0.21 0.10 0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 12.9 0.363 0.980 161.9 287.8 91.9 20.5 eV 0.0420 0.0581 3.22 6.71 6.78 6.71 0.0065 þ0.0004 þ0.12 þ0.75 þ1.00 þ1.75 w0.2/h (N ¼ 275, hr ¼ 45.0 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.88  0.17 (s ¼ 2.47  0.05) Ib: Hb ¼ 111.0  0.91 Mv; Hmax ¼ 100.8 þ 1.07 Mv; He ¼ 95.8 þ 1.45 Mv (N ¼ 158) IIb: Hb ¼ 100.5  0.79 Mv; Hmax ¼ 94.8 þ 0.28 Mv; He ¼ 89.9  0.31 Mv (N ¼ 42) Ib: r w 0.64 g/cm3 (a1 ¼ 0.072 km, a2 ¼ 7.07/s) IIb: r w 3.6 g/cm3 (a1 ¼ 0.0055 km, a2 ¼ 21.11/s) dpossibly Na poor/free From c and s: w42,000 y; From model: w35,000 e

Meteoroid density: Age: Source:

Brief history: First recognized from CAMS video data by [1] from R.A. ¼ 330.7 , Decl. ¼ 4.3 and Vg ¼ 63.2 km/s around lo ¼ 93 . Low i and q cause rapid rotation of nodal line. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409. June 21 (lo ¼ 91 )

410 DPI d delta Piscids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1864-Jul-28.0 TDB

Long-period comet, TJ ¼ 1.06  0.46 Annual shower June 17e28 (lo ¼ 87 e98 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 90.8 10.2 5.5 280.5 þ1.0 70.1 þ0.66 þ0.23 0.30 0.05 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 54.5 0.920 0.983 178.3 143.8 90.8 235.0 0.0143 0.0930 0.86 3.49 2.15 3.49 þ0.0053 0.0004 þ0.08 0.96 þ1.00 þ1.96 w0.9/h (N ¼ 318, hr ¼ 32.3 , m(Mv¼ 0) ¼ 0.13 g) c ¼ 3.12  0.14 (s ¼ 2.23  0.05) I: Hb ¼ 114.2  0.97 Mv; Hmax ¼ 107.0 þ 0.93 Mv; He ¼ 102.3 þ 1.51 Mv (N ¼ 151) I: r w 0.39 g/cm3 (a1 ¼ 0.037 km, a2 ¼ 9.74/s) From s: w40,000 y, while c suggests 77,000 y; From model: w 50,000 y C/1864 N1 (Tempel) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 249.2 0.909 0.996 178.2 151.6 97.7 249.3

eV

Brief history: First recognized from single station video data in IMO Video Meteor Network by [1] from R.A. ¼ 10.9 , Decl. ¼ þ5.5 and Vg ¼ 71.0 km/s around lo ¼ 92 . Confirmed from triangulated observations by [2]. Source C/1864 N1 identified by [3]. Retrograde, low i orbit: rapid nodal line rotation, small i dispersion growth. Name and number by [1]. References: [1] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [2] Jenniskens P., et al. (2016) Icarus 266, 355e370; [3] Jenniskens P., et al. (2021) Icarus 365, id. 114469.

172

Allsky: Video and Radar

173

May

June 5 (lo ¼ 74 )

764 TEL d Telescopiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet or asteroid, TJ ¼ 6.34  0.74 Annual shower May 1eJune 17 (lo ¼ 40 e86 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 74.3 305.4 46.3 222.2 26.4 30.7 þ0.39 0.57 0.52 þ0.50 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.86 0.211 0.757 51.8 147.9 254.3 42.0 0.0688 0.0942 9.22 4.89 9.23 4.89 0.0061 þ0.0074 0.64 þ0.23 þ1.00 þ1.23 w0.2/h (N ¼ 212, hr ¼ 59.6 , m(Mv ¼ 0) ¼ 0.14 g) c ¼ 6.18  1.13 (s ¼ 2.98  0.19) IIb: Hb ¼ 93.2  0.29 Mv; Hmax ¼ 84.9 þ 1.43 Mv; He ¼ 80.1 þ 1.48 Mv (N ¼ 198) IIb: r w 1.49  0.41 g/cm3 (a1 ¼ 0.065 km, a2 ¼ 7.00/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

April 28eMay 31 (lo ¼ 38 e71 ) R.A. ( ) Decl. ( ) lo ( ) 59.4 283.3 50.6 þ1.14 þ0.46 a (AU) q (AU) e 0.87 0.244 0.721 0.0616 0.0873 0.0042 0.0048 0.94 0.273 0.710 N ¼ 19,670

Age: Source:

From c: 33,000 y e

l ( ) 221.9 0.17 i ( ) 46.8 10.61 0.31 55.5

b ( ) 28.1 þ0.40 u ( ) 145.0 6.69 þ0.29 139.5

Vg (km/s) 29.6 þ0.01 U ( ) 239.4 7.99 þ1.00 243.0

P ( ) 24.4 6.69 þ1.29 22.5

eV

e R[S] e R[1]

Brief history: Part of southern June Aquilids Complex. Shower leads up to #165 SZC, the Southern June Aquilids. Shower first reported from SAAMER radar data by [1] from R.A. ¼ 291.0 , Decl. ¼ 53.6 and Vg ¼ 31.6 km/s around lo ¼ 63.0 . Shower is only weakly detected in video data here, consistent with a very high magnitude distribution index. Name and number assigned by [1]. References: [1] Pokorny P., et al. (2017) Icarus 290, 162e182.

174

Allsky: Video and Radar

175

June

May 23 (lo ¼ 62 )

361 TSR d theta Serpentids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ 6.66  0.42 Annual shower, part of a ¼ 0.86 AU, i ¼ 60 group May 18e26 (lo ¼ 57 e65 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 62.1 286.2 þ4.2 225.8 þ26.6 32.0 þ0.64 0.04 0.28 0.04 þ0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.82 0.189 0.768 56.3 330.9 62.1 33.2 eV 0.0199 0.0229 4.25 2.89 1.56 2.89 0.0003 0.0022 1.95 þ0.42 þ1.00 þ1.42 0.93 0.237 0.745 54.3 322.7 65.0 27.7 e R[1] w0.08/h (N ¼ 21, hr ¼ 48.6 , m(Mv ¼ 0) ¼ 0.13 g) c ¼ 3.80  0.26 (s ¼ 2.45  0.07) Low beginning heights: III: Hb ¼ 90.8 þ 0.04 Mv; Hmax ¼ 87.5 þ 0.22 Mv; He ¼ 82.9 þ 0.98 Mv (N ¼ 18) III: r w 1.5 g/cm3 (a1 ¼ 0.018 km, a2 ¼ 12.92/s) dpossibly Na free From c: 27,000 y 489900 (2008 KP) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.10 0.232 0.790 59.8 345.0 62.4 47.4

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

Brief history: Part of Aquilid Complex (with #151, 766, and 356, amongst others), see the finding charts of Fig. 5.7 that plot radiant and speed as a function of solar longitude for meteors detected along the toroidal arc. First reported from CMOR radar observations by [1] from R.A. ¼ 284.0 , Decl. ¼ þ6.0 and Vg ¼ 32.0 km/s around lo ¼ 65.0 . Confirmed from video observations here. 2008 KP proposed as parent body by [1]. Name and number by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81.

FIG 5.7 Along the northern toroidal arc: distribution of radiant and speed as a function of solar longitude.

176

Allsky: Video and Radar

June

177

178

Allsky: Video and Radar

July

July 2 (lo ¼ 101 )

765 ASG d alpha Sagittariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ þ7.14  0.55 Annual shower June 2eJuly 22 (lo ¼ 78 e120 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 100.5 328.4 37.9 225.4 24.6 27.9 þ0.99 þ0.47 0.11 þ0.18 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.76 0.203 0.752 43.7 154.1 280.5 70.3 0.0342 0.1235 10.5 7.44 17.4 7.44 0.0015 þ0.0020 0.19 þ0.05 þ1.00 þ1.05 w0.2/h (N ¼ 323, hr ¼ 63.2 , m(Mv ¼ 0) ¼ 0.18 g) c ¼ 4.75  0.58 (s ¼ 2.69  0.12) Component IIb has low He, Ke < 79, like III: IIb: Hb ¼ 91.7  0.17 Mv; Hmax ¼ 84.0 þ 1.32 Mv; He ¼ 79.2 þ 1.67 Mv (N ¼ 310) IIb: r w 1.5 g/cm3 (a1 ¼ 0.048 km, a2 ¼ 7.52/s) From c: 36,000 y e

Meteoroid density: Age: Source:

179

eV

Brief history: Leads up to #165 SZC, part of the Southern June Aquilids complex. First identified in SAAMER radar observations by [1] from R.A. ¼ 317.9 , Decl. ¼ 30.6 at this solar longitude. Perhaps two showers. The reported showers 762, 763, 764, and 765 form a sequence of increasing longitude and latitude with solar longitude, but are not continuous. Number and name by [1]. References: [1] Pokorny P., et al. (2017) Icarus 290, 162e182. July 7 (lo ¼ 105 )

366 JBP d July beta Pegasids

Dynamic type: Shower type: Years of meteor outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, TJ ¼ þ8.02  0.43 Annual shower, part of a ¼ 0.86 AU, i ¼ 60 group e July 1e13 (lo ¼ 99 e111 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 105.5 333.1 þ21.9 239.0 þ30.4 27.7 þ0.18 þ0.48 0.81 0.22 0.25 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.68 0.200 0.715 55.7 340.3 105.5 85.6 eV 0.0376 0.0441 8.09 6.41 2.60 6.41 0.0009 þ0.0020 1.30 0.19 þ1.00 þ0.81 0.62 0.216 0.651 67.4 357.1 100.0 97.1 e R[1] w1/h (N ¼ 385, hr ¼ 58.3 , m(Mv ¼ 0) ¼ 0.18 g) c ¼ 4.63  0.15 (s ¼ 2.66  0.03) IIb: Hb ¼ 91.4  0.15 Mv; Hmax ¼ 86.9 þ 0.53 Mv; He ¼ 82.9 þ 0.88 Mv (N ¼ 300) IIb: low F ¼ 0.53, fragile IIb: r  1.4 g/cm3 (a1 ¼ 0.057 km, a2 ¼ 7.88/s) dlower if fragile From c: 35,000 y; sU < su: perhaps only part of node range considered e

Brief history: Shower leads up to #164 NZC, the Northern June Aquilids. First identified in CMOR radar observations by [1] from R.A. ¼ 349.1 , Decl. ¼ þ34.4 and Vg ¼ 27.8 km/s around lo ¼ 100 . Part of the June Aquilids Complex, group with #151 and 161, amongst others. Number and name by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81.

180

Allsky: Video and Radar

181

June

June 10 (lo ¼ 80 )

1129 JTT d June theta2 Sagittariids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

Jupiter-family comet or asteroid, sunskirter, TJ ¼ þ5.25  0.48 Episodic shower (1957/58), (1980?), 2015/16, 2020/21 June 7e14 (lo ¼ 77 e84 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 80.4 304.8 33.0 218.6 13.0 36.4 þ0.18 þ0.48 0.74 þ0.43 þ0.17 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.03 0.073 0.929 49.2 158.2 260.4 58.7 eV 0.0121 0.0187 5.52 1.73 2.08 1.73 þ0.0001 þ0.0008 1.87 0.17 þ1.00 þ0.83 w0.7/h (N ¼ 198, hr ¼ 65.8 , m(Mv ¼ 0) ¼ 0.09 g) c ¼ 4.68  0.26 (s ¼ 2.68  0.06) Component Ia has unusually high Kc > 104, but also low N: Ia: Hb ¼ 111.1  2.72 Mv; Hmax ¼ 99.1  0.13 Mv; He ¼ 93.8 þ 0.47 Mv (N ¼ 18) IIb: Hb ¼ 95.5  0.66 Mv; Hmax ¼ 85.8 þ 1.18 Mv; He ¼ 80.5 þ 1.47 Mv (N ¼ 50) IIIb: Hb ¼ 88.0 þ 0.40 Mv; Hmax ¼ 82.7 þ 1.36 Mv; He ¼ 78.6 þ 1.51 Mv (N ¼ 128) Ia: r w 0.73 g/cm3 (a1 ¼ 0.123 km, a2 ¼ 6.01/s) dlow N IIb: w0.70 g/cm3 (a1 ¼ 0.143 km, a2 ¼ 6.24/s) IIIb: w2.7 g/cm3 (a1 ¼ 0.0295 km, a2 ¼ 12.17/s) dpossibly Na free June 3e14 (lo ¼ 73 e84 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 79.4 302.2 34.7 218.0 14.3 33.8 þ0.17 þ0.66 0.74 þ0.62 þ0.42 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.98 0.101 0.899 39.9 155.6 259.4 54.8 e R[S] 0.0401 0.0480 12.49 5.84 2.07 5.84 þ0.0023 þ0.0064 0.96 0.21 þ1.00 þ0.79 N ¼ 10,020

Age: Source: Orbital elements (J2000.0) Epoch 1994-Feb-17.0 TDB

From c: 13,000 y, likely younger C/2009 U10 (SOHO) a (AU) q (AU) e N 0.0544 1.000

Meteoroid density:

i ( ) 32.2

u ( ) 323.5

U ( ) 100.3

duncertain P ( ) 63.8

Brief history: Part of #295 June Aquilids Complex. First added to Working List from a detection in CAMS data during an outbursts in 2021 [1,5]. Shower may have been known before as “Sagittariids.” [2] detected 30/h meteors with University of Adelaide radar in 1957 and 1958, but did not detect the shower in 1952, 1953, 1954, and 1956. Observations in 1968 and 1969 also came up empty [3]. Meteors radiated from R.A. ¼ 307 , Decl. ¼ 35 in 1957 and R.A. ¼ 301 ,  Decl. ¼ 36 in 1958. Despite the steep magnitude distribution index, it is possible the shower was seen visually in 1980, when “alpha Microscopiids” radiated from R.A. ¼ 305 , Decl. ¼ 36 with rate ZHR w 1.5/h on June 11 [4]. ZHR profile from video data in Fig. 5.8. Taken together, the observaFIG 5.8 ZHR profile. tions suggest a periodic return every 5.00  0.23 y, but the orbital period of the detected meteoroids is much smaller. [6] linked the Northern June Aquilids to SOHO comet C/2009 U10. It is possible that this shower is due to a related comet fragment [5]. Number and name by [1]. References: [1] Jenniskens P., et al. (2021) CBET 4980. Ed.: D. W. E. Green, Cambridge: I.A.U. Central Bureau for Astronomical Telegrams, pp. 1e1; [2] Weiss A. A. (1960) MNRAS 120, 397e400; [3] Gatrell G., Elford W. G. (1975) AuJPh 28, 591e620; [4] Kronk G. W. (2014) Meteor Showers, an Annotated Catalog. New York: Springer, p. 126e127; [5] Jenniskens P. (2021) eMeteorNews 6, 381,382; [6] Holman D., Jenniskens P. (2012) JIMO 40, 166e170.

182

Allsky: Video and Radar

164 NZCdNorthern June Aquilids

June

183

July 16 (lo ¼ 115 )

327 BEQ d beta Equuleids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, sunskirter, TJ ¼ þ4.05  0.60 Annual shower July 9e22 (lo ¼ 106 e120 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 115.2 319.8 þ1.9 208.1 þ16.6 34.0 þ0.84 0.00 0.16 0.27 þ0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.03 0.073 0.929 49.2 158.2 260.4 58.7 eV 0.0106 0.0353 4.49 4.25 3.35 4.25 0.0017 þ0.0030 0.35 þ0.02 þ1.00 þ1.02 w0.3/h (N ¼ 204, hr ¼ 50.6 , m(Mv ¼ 0) ¼ 0.11 g) c ¼ 3.90  0.06 (s ¼ 2.48  0.02) IIa: Hb ¼ 99.4 þ 0.20 Mv; Hmax ¼ 91.1 þ 1.16 Mv; He ¼ 85.9 þ 1.14 Mv (N ¼ 28) IIb: Hb ¼ 93.7  0.09 Mv; Hmax ¼ 87.0 þ 1.22 Mv; He ¼ 83.0 þ 1.51 Mv (N ¼ 109) IIa: r w 1.01 g/cm3 (a1 ¼ 0.0495 km, a2 ¼ 5.49/s) IIb: r w 1.8 g/cm3 (a1 ¼ 0.0545 km, a2 ¼ 8.92/s) dpossibly Na poor/free From c: 11,000 y e

Meteoroid density: Age: Source:

Brief history: Shower leads up to #164 NZC, the Northern June Aquilids. First identified in CMOR radar observations by [1] from R.A. ¼ 321.5 , Decl. ¼ þ8.7 and Vg ¼ 31.6 km/s around lo ¼ 106.5 . Part of #295 June Aquilids Complex. Component assigned #327 here peaks later and has lower declination. Number and name by [1]. References: [1] Brown P., et al. (2008) Icarus 195, 317e339. July 11 (lo ¼ 109 )

1189 TZA d 20 Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, sunskirter, TJ ¼ þ3.49  0.28 Annual shower July 9e13 (lo ¼ 107 e111 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 108.7 323.1 1.4 216.2 þ12.4 41.5 þ0.56 þ0.41 0.32 þ0.21 þ0.19 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.55 0.064 0.959 59.8 336.1 108.7 84.8 0.0044 0.0051 3.38 0.73 0.72 0.73 þ0.0027 þ0.0000 0.00 0.74 þ1.00 þ0.26 w0.12/h (N ¼ 30, hr ¼ 50.2 , m(Mv¼ 0) ¼ 0.07 g) c ¼ 2.70  0.14 (s ¼ 2.05  0.06) III: Hb ¼ 92.5  0.13 Mv; Hmax ¼ 86.2 þ 0.96 Mv; He ¼ 82.1 þ 0.77 Mv (N ¼ 27) III: r w 3.2 g/cm3 (a1 ¼ 0.019 km, a2 ¼ 10.73/s) From c: 6000 y e

Brief history: First reported here.

eV

184

Allsky: Video and Radar

July

185

July 16 (lo [ 113 )

326 EPG d epsilon Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, sunskirter, TJ ¼ þ6.93  0.74 Annual shower July 7e23 (lo ¼ 105 e120 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 113.2 330.2 þ10.5 222.3 þ21.6 29.1 þ0.73 þ0.03 0.27 0.24 0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.80 0.148 0.812 44.0 334.4 113.2 87.7 eV 0.0341 0.0455 7.65 5.81 4.01 5.81 0.0006 þ0.0015 0.58 0.10 þ1.00 þ0.90 0.757 0.173 0.771 55.4 334.9 105.2 80.1 e R[1] w0.7/h (N ¼ 489, hr ¼ 52.9 , m(Mv ¼ 0) ¼ 0.16 g) c ¼ 4.26  0.18 (s ¼ 2.57  0.04) IIa: Hb ¼ 96.7  0.37 Mv; Hmax ¼ 87.7 þ 1.35 Mv; He ¼ 83.4 þ 1.53 Mv (N ¼ 75) IIb: Hb ¼ 91.4 þ 0.04 Mv; Hmax ¼ 87.0 þ 0.72 Mv; He ¼ 83.3 þ 0.90 Mv (N ¼ 322) IIa: r w 0.88 g/cm3 (a1 ¼ 0.219 km, a2 ¼ 3.56/s) IIb: r w 1.0  0.7 g/cm3 (a1 ¼ 0.085 km, a2 ¼ 6.68/s) dpossibly Na poor/free From c: 24,000 y e

Meteoroid density: Age: Source:

Brief history: Shower leads up to #164 NZC, the Northern June Aquilids. Part of the June Aquilids Complex. Perhaps first identified in CMOR radar observations by [1]. Activity period June 28eJuly 7 (97 e105 ) from R.A. ¼ 324.3 , Decl. ¼ þ13.2 , Vg ¼ 30.0 km/s [2]. Not sure the shower is correctly named, as the CMOR shower #326 was said to make a complex with #364, 357 and 360 [2], all of which are not confirmed here. Detected in video data by [3]. Number and name by [1]. Fig. 5.9 shows related shower #151. References: [1] Brown P., et al. (2008) Icarus 195, 317e339; [2] Brown P., et al. (2010) Icarus 207, 66e81; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354.

FIG 5.9

The epsilon-Aquilids meteoroid stream (#151).

186

Allsky: Video and Radar

July

July 5 (lo ¼ 103 )

802 ADS d June Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.02  0.65 Annual shower June 21eJuly 18 (lo ¼ 90 e115 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 102.8 344.8 14.4 237.1 7.4 61.4 þ0.77 þ0.30 0.19 0.01 0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.78 0.321 0.960 160.2 113.7 282.8 37.4 0.0408 0.037 1.97 5.91 7.34 5.91 0.0046 þ0.0010 0.15 þ0.53 þ1.00 þ1.54 w0.2/h (N ¼ 195, hr ¼ 45.4 , m(Mv ¼ 0) ¼ 0.02 g) 3.40  0.25 (s ¼ 2.33  0.08) IIa: Hb ¼ 108.8  0.99 Mv; Hmax ¼ 97.9 þ 1.37 Mv; He ¼ 92.6 þ 1.85 Mv (N ¼ 161) III: Hb ¼ 96.6  0.04 Mv; Hmax ¼ 92.2 þ 0.83 Mv; He ¼ 88.0 þ 0.68 Mv (N ¼ 11) IIa: r w 3.3 g/cm3 (a1 ¼ 0.018 km, a2 ¼ 20.55/s) III: Possibly Na poor/free From c and s: w31,000 y e

Meteoroid density: Age: Source:

187

eV

Brief history: Confusing area, not certain that only one shower was extracted here. Low i and q cause rapid rotation of nodal line. Perhaps first glimpsed by visual observers in the 19th century, with [2] giving a radiant at R.A. ¼ 354 , Decl. ¼ 16 in July. Perhaps video detected by [1], who provided a position at R.A. ¼ 333.6, Decl. ¼ 18.5 and Vg ¼ 60.9 km/s centered on lo ¼ 91.7 from 11 meteors detected by the BRAMON, EDMOND and SonotaCo networks. Name and number adopted as given by [1]. References: [1] Amaral L. S., et al. (2020) JIMO 48, 69e88; [2] Heis E., Neumayer G. (1867) On Meteors in the Southern Hemisphere. Mannheim: J. Schneider, 25 pp (p. 15). July 16 (lo ¼ 114 )

868 PSQ d psi3 Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.47  0.60 Annual shower July 8e23 (lo ¼ 106 e121 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 113.8 341.4 13.9 223.7 5.5 54.3 þ0.72 þ0.25 0.26 0.03 0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.21 0.056 0.994 147.3 153.9 293.4 86.9 eV 0.0133 0.0071 5.39 4.00 3.34 4.00 0.0026 þ0.0004 0.87 þ0.48 þ1.00 þ1.48 0.07/h (N ¼ 55, hr ¼ 49.2 , m(Mv ¼ 0) ¼ 0.03 g) 3.65  0.42 (s ¼ 2.41  0.12) III: Hb ¼ 97.4  0.75 Mv; Hmax ¼ 92.1 þ 0.60 Mv; He ¼ 87.3 þ 0.76 Mv (N ¼ 37) III: r w 2.7 g/cm3 (a1 ¼ 0.0315 km, a2 ¼ 10.89/s) dpossibly Na poor/free From c and s: w6000 y e

Brief history: Shower first detected by [1] from R.A. ¼ 347.4 , Decl. ¼ 11.9 and Vg ¼ 53.1 km/s around lo ¼ 120.5 . Low perihelion distance suggests loss of sodium. Only deeply penetrating meteoroids detected. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29.

188

Allsky: Video and Radar

189

July

July 9 (lo ¼ 107 )

768 ZPH d zeta Phoenicids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, toroidal shower, TJ ¼ þ1.36  0.62 Annual shower June 27eJuly 20 (lo ¼ 94 e118 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 106.9 12.6 52.8 233.9 51.4 45.0 þ0.80 þ0.53 þ0.16 þ0.11 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 4.54 0.824 0.822 79.2 54.9 287.0 342.5 eV 0.0297 0.125 3.12 5.48 5.43 5.48 0.0009 0.0031 þ0.17 þ0.18 þ1.00 þ1.18 w0.5/h (N ¼ 258, hr ¼ 57.8 , m(Mv ¼ 0) ¼ 0.06 g) 4.23  0.52 (s ¼ 2.57  0.13) Two components (Ib has low He with Ke < 82): Ib: Hb ¼ 107.5  1.49 Mv; Hmax ¼ 94.9 þ 1.63 Mv; He ¼ 89.3 þ 1.14 Mv (N ¼ 49) III: Hb ¼ 94.6  0.16 Mv; Hmax ¼ 89.8 þ 0.20 Mv; He ¼ 84.2 þ 0.56 Mv (N ¼ 175) Ib: r w 1.4 g/cm3 (a1 ¼ 0.055 km, a2 ¼ 6.64/s) III: r w 2.4 g/cm3 (a1 ¼ 0.0455 km, a2 ¼ 9.23/s) dpossibly Na poor/free

Meteoroid density: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

July 2e20 (lo ¼ 99 e118 ) lo ( ) R.A. ( ) Decl. ( ) 108.2 14.3 51.0 þ0.90 þ0.52 a (AU) q (AU) e 1.63 0.770 0.535 0.077 0.173 0.0038 0.0083 2.14 0.821 0.616 N ¼ 5773

Age:

From c and s: w61,000 y

l ( ) 236.6 0.20 i ( ) 74.7 5.97 0.15 76.9

b ( ) 50.9 þ0.07 u ( ) 71.8 21.04 þ2.18 60.3

Vg (km/s) 39.5 0.20 U ( ) 288.2 4.23 þ1.00 285.0

P ( ) 0.1 21.04 þ2.18 345.3

e R[S] e R[2]

Brief history: First identified instrumentally by [1] from SAAMER radar observations from R.A. ¼ 13.7 , Decl. ¼ 52.8 and Vg ¼ 41.7 km/s around lo ¼ 105 . Confirmed from video data by [2], with video orbits being slightly more elongated. Name and number by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182; [2] Jenniskens P., et al. (2018) PPS 154, 21e29. July 14 (lo ¼ 111 )

176 PHE d July Phoenicids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ þ4.32  0.42 Annual shower July 4e22 (lo ¼ 101 e119 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 110.7 29.1 48.3 249.6 54.4 38.2 þ0.88 þ0.58 þ0.39 þ0.12 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) 1.34 0.897 0.339 74.8 58.9 290.7 0.0464 0.116 3.87 13.53 3.42 þ0.0009 0.0058 þ0.21 þ0.30 þ1.00 1.26 0.890 0.291 74.8 63.3 292.1 N ¼ 7200 (m(Mv ¼ 0) ¼ 0.08 g) e r ¼ 0.2e2.1 g/cm3 e e

eR

P ( ) 349.4 13.53 þ1.30 345.3

e R[S] e R[3]

190

Allsky: Video and Radar

July

191

Brief history: First reported from Adelaide radar observations by [1]. During the 1957 and 1958 observations between July 5 and 19, with a sharp maximum on July 14 at lo ¼ 112.7 , a shower was detected centered on R.A. ¼ 34.1 , Decl. 46.4 , drifting with þ1.05 in R.A. and þ0.54 in Decl. Absent in video observations [2]. Because entry speed is relatively high, the actual semi-major axis could be higher and TJ lower. Name by [1], number by [2]. This is not the visual shower known before [2]. That shower was detected in SAAMER radar observations by [3] and named “sigma Phoenicids” (ZPH). This is now in the list as the “psi Phoenicids” (PPH, #769). References: [1] Weiss A. A. (1960) AuJPh 13, 522e531; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 709 pp.; [3] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182. July 21 (lo ¼ 119 )

182 OCY d omicron Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number detected: Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.08  0.91 Annual shower July 1eAugust 8 (lo ¼ 100 e136 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 118.7 307.1 þ52.6 221.2 þ66.8 35.1 þ0.60 þ0.19 þ0.04 0.07 0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.10 0.936 0.818 57.7 214.9 118.7 332.3 0.0339 0.133 3.64 6.01 9.09 6.01 0.0031 0.0007 þ0.00 þ0.19 þ1.00 þ0.79 N ¼ 598 (hr ¼ 68.2 , m(Mv¼0) ¼ 0.10 g) 2.5  0.8, B ¼ 0.13  0.03 [4] 2.52  0.17 (s ¼ 2.00  0.07); 2.7 [4] Component IIb has low He, Ke < 79, like III: Ib: Hb ¼ 102.4  1.14 Mv; Hmax ¼ 92.1 þ 0.86 Mv; He ¼ 87.3 þ 1.17 Mv (N ¼ 309) IIb: Hb ¼ 92.5  0.88 Mv; Hmax ¼ 86.1 þ 0.26 Mv; He ¼ 81.9 þ 0.52 Mv (N ¼ 61) Ib: r w 0.71 g/cm3 (a1 ¼ 0.067 km, a2 ¼ 5.14/s) IIb: Possibly Na poor/free From c: w26,000 y; from s (tail): w63,000 y; Radiant drift: dU > du e

Meteoroid density: Age: Source:

eV

Brief history: Shower at R.A. ¼ 304.5 , Decl. ¼ þ49.7 and Vg ¼ 39.4 km/s, was first detected among photographed orbits by [1]. Independently, a visual shower of “j-Cygnids” was detected on July 20/21 and 21/22, 1991, by [2] with a radiant at R.A. ¼ 300 , Decl. ¼ þ52 , with a ZHR ¼ 2.5  0.8. Video data show a diffuse shower of long duration. Name by [1], number by [3]. References: [1] Babadzhanov P. B., Kramer E. N. (1965) SCoA 11, 67e79; [2] Jenniskens P., Wiertz M., de Lignie M. (1991) Radiant, Journal of the DMS 13, 20e25; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [4] Jenniskens P. (1994) AA 287, 990e1013.

192

Allsky: Video and Radar

July

193

July 27 (lo ¼ 125 )

184 GDR d July gamma Draconids

Dynamic type: Shower type: Years of outbursts:

Mellish-type shower, TJ ¼ þ1.11  0.39 Annual shower, episodic outbursts of bright meteors 2011: lo ¼ 124.66  0.37 , c ¼ 1.8  0.3, N ¼ 25 [5] 2016: lo ¼ 125.128  0.018 , N ¼ 100; 125.132 [12]; CMOR: 125.17 [9]; lo ¼ 125.129 , ZHR w 100/h, W ¼ 0.02 , c ¼ 2.0 [8]; 2020: lo ¼ 125.118  0.027 , N ¼ 27 July 19eAugust 2 (lo ¼ 117 e131 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 125.1 279.9 þ50.5 167.0 þ73.2 27.4 þ0.01 þ0.07 0.92 þ0.07 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 28.4 0.978 0.972 40.2 202.4 125.1 327.6 eV 0.0045 0.0740 1.26 1.45 1.79 1.45 þ0.0007 þ0.0039 0.16 0.25 þ1.00 þ0.75 N ¼ 944 (hr ¼ 67.7 , m(Mv ¼ 0) ¼ 0.19 g) Annual: w0.8/h; 1.8  0.2 [6]; 0.35  0.05/h [11] Annual: 2.89  0.09 (s ¼ 2.15  0.03); 3.0 [7] Ib: Hb ¼ 99.5  1.19 Mv; Hmax ¼ 88.9 þ 1.15 Mv; He ¼ 84.1 þ 1.59 Mv (N ¼ 430) Ib: r w 1.3  0.3 g/cm3 (a1 ¼ 0.087 km, a2 ¼ 3.28/s) Mg0.59 Fe0.76 Na0.042 (N ¼ 2), weak O emission From c: w43,000 y; from s: w15,000 y C/2013 K1 (Christensen) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 79.8 0.948 0.988 42.3 171.3 125.9 297.2 C/1919 Q2 (Metcalf) duncertain 5036.8 1.115 0.9998 46.4 185.8 122.1 307.9

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number detected: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1913-May-31.0 TDB Source: Epoch 1919-Sep-18.0 TDB

Brief history: Shower was first detected by [1] from 3 meteors with anomalous radiant and speed among 185 photographed meteors during 1957 June and 1959 December. The meteors were photographed on July 26/27 and radiated from R.A. ¼ 278.7 , Decl. ¼ þ49.6 , with Vg ¼ 26.4 km/s. [2] identified 3 Harvard Meteor Project photographed meteors in 1952e1954 from R.A. ¼ 271 , Decl. ¼ þ59 . Shower named “o Draconids” and proposed source long-period comet C/1919 Q2. Detected in SonotaCo network video observations by [4]. Called group “A,” separate from #12 KCG by [13]. Confirmed from single-station VMN data by [14] and triangulated data by [5]. CAMS BeNeLux detected an outburst in the night of FIG 5.10 ZHR profile. July 27/28, 2016, when rates peaked at ZHR w 30e100/h, corresponding to w0.034 km2/h [8]. That outburst was also detected by CMOR [9] and forward meteor scatter networks [10]. During analysis for this work, we noticed the outburst in 2020. Annual activity curve in Fig. 5.10. Name and number by [3]. References: [1] Babadzhanov P. (1963) SCoA 7, 287e291; [2] Cook A. F., et al. (1973) SCoA 15, 1e5; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [4] Kanamori T. (2009) JIMO 37, 55e62; [5] Holman D., Jenniskens P. (2012) JIMO 40, 36e40; [6] Molau S. (2013) JIMO 41, 169e172; [7] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [8] Molau S., et al. (2016) JIMO 44, 205e210; [9] Roggemans P. (2016) eMeteorNews 1, 80e81; [10] Steyaert C., Brower J. (2017) Proceedings IMC 2017, Petnica: IMO, p. 128e131; [11] Molau S., et al. (2019) JIMO 47, 116e120; [12] Molau S., et al. (2016) JIIMO 44, 205e210; [13] Koseki M. (2014) JIMO 42, 181e197; [14] Molau S., Rendtel J. (2009) JIMO 37, 98e121.

194

Allsky: Video and Radar

August

195

Aug. 5 (lo ¼ 133 )

798 ACD d August Caelids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, toroidal shower, TJ ¼ þ0.58  0.47 Annual shower July 3eSeptember 7 (lo ¼ 101 e165 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 132.8 68.4 36.7 283.1 57.6 47.8 þ0.57 þ0.39 þ0.03 þ0.26 þ0.18 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 13.0 0.994 0.922 83.6 343.6 312.8 297.3 eV 0.0248 0.173 7.01 10.79 11.47 10.79 0.0005 þ0.0018 þ0.39 0.14 þ1.00 þ0.86 w3/h (N ¼ 2826, hr ¼ 49.1 , m(Mv ¼ 0) ¼ 0.05 g) 3.33  0.14 (s ¼ 2.31  0.05) I: Hb ¼ 108.7  1.30 Mv; Hmax ¼ 96.2 þ 1.62 Mv; He ¼ 90.9 þ 2.10 Mv (N ¼ 2331) IIb: Hb ¼ 98.5  0.41 Mv; Hmax ¼ 89.2 þ 1.22 Mv; He ¼ 84.3 þ 1.45 Mv (N ¼ 167) IIIb: Hb ¼ 92.5 þ 0.25 Mv; Hmax ¼ 86.9 þ 1.42 Mv; He ¼ 82.4 þ 1.60 Mv (N ¼ 208) I: r w 0.62  0.17 g/cm3 (a1 ¼ 0.075 km, a2 ¼ 5.12/s) IIb: r w 2.0  0.6 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 7.58/s) dpossibly Na poor IIIb: r w 3.0  0.8 g/cm3 (a1 ¼ 0.031 km, a2 ¼ 10.46/s) dpossibly Na free From c: w97,000 y; from s: (tail): w193,000 y; From model: w200,000 y e

Meteoroid density:

Age: Source:

Brief history: Strong shower was incorrectly identified by [1] as shower #176. Name and number from 10 video-detected meteors by [2] from R.A. ¼ 68.6 , Decl. ¼ 38.2 and Vg ¼ 44.9 km/s around lo ¼ 131.3 . Confirmed here. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] de Sousa Trindade L., Zurita M., Dal’ava A., Gonçalves Silva G., Bella Di Pietro C. A. (2019) JIMO 47, 184e187. Aug. 12 (lo ¼ 138 )

822 NUT d nu Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1797-Jul-09.6 TDB

Long-period comet, TJ ¼ 0.26  0.36 Annual shower July 22eSeptember 3 (lo ¼ 120 e160 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 138.1 76.9 þ2.3 298.0 20.2 62.2 þ0.89 þ0.01 0.06 0.06 þ0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 12.7 0.562 0.957 135.9 275.2 318.1 232.1 eV 0.0385 0.0558 1.93 5.21 10.77 5.21 þ0.0017 0.0009 0.07 þ0.19 þ1.00 þ1.19 w0.3/h (N ¼ 214, hr ¼ 29.5 , m(Mv¼ 0) ¼ 0.02 g) 3.48  0.27 (s ¼ 2.35  0.09) Ib: Hb ¼ 110.9  0.50 Mv; Hmax ¼ 103.5 þ 0.87 Mv; He ¼ 98.7 þ 1.20 Mv (N ¼ 165) Ib: r w 0.72 g/cm3 (a1 ¼ 0.0495 km, a2 ¼ 6.34/s) From c and s: w58,000 y; From model: w60,000 y C/1797 P1 (Bouvard-Herschel) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.525 (1.000) 129.4 332.1 279.7 251.8

Brief history: Active over long 40 interval of solar longitude. Shower first detected by [1] from R.A. ¼ 64.3 , Decl. ¼ þ1.6 and Vg ¼ 6.18 km/s around lo ¼ 123.3 . Parent body identified by [2]. Possible twin-shower of #506 FEVdFebruary epsilon Virginids (part of 20 COMdComae Berenicids). Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29; [2] Jenniskens P., et al. (2021) Icarus 365, id. 114469.

196

Allsky: Video and Radar

12 KCGdkappa Cygnids

August

Aug. 13 (lo ¼ 141 )

197

12 KCG d kappa Cygnids

Jupiter-family comet, TJ ¼ þ2.54  0.20 Episodic outbursts (1871) 1879, 1893, 1901, 1950, 1957, 1978, 1985, 1993, 1999, 2007, 2013/2014, 2020/2021 July 10eSeptember 11 (lo ¼ 108 e168 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 140.8 285.6 þ51.4 163.9 þ72.9 22.7 þ0.60 þ0.79 þ1.15y þ0.60y þ0.19 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.34 0.976 0.710 34.7 204.0 140.8 345.3 eV 0.0093 0.0538 3.04 4.38 11.50 4.38 þ0.0012y 0.0006 þ0.46 0.43 þ1.00 þ0.57 N ¼ 2754 (hr ¼ 66.5 , m(Mv ¼ 0) ¼ 0.29 g) In outburst years: 2.3  0.4, B ¼ 0.069  0.005 [19]; 2014: 3.3  0.2/h [21] c ¼ 1.74  0.02 (s ¼ 1.60  0.01) c ¼ 1.9  0.4 from 30 photographed fireballs [2]; 2.2 [19] Lightcurve: Ib: Hb ¼ 97.1  1.35 Mv; Hmax ¼ 87.1 þ 1.35 Mv; He ¼ 83.2 þ 1.25 Mv (N ¼ 1130) III: Hb ¼ 84.8  0.24 Mv; Hmax ¼ 81.0 þ 0.61 Mv; He ¼ 77.4 þ 0.56 Mv (N ¼ 83) Meteoroid density: r ¼ 2.2  1.7 g/cm3, porosity 12% [25] Ib: r w 1.08  0.18 g/cm3 (a1 ¼ 0.086 km, a2 ¼ 3.86/s) III: r  2.3  0.9 g/cm3 (a1 ¼ 0.0885 km, a2 ¼ 5.19/s) dpossibly Na free Spectroscopy: Ib: Mg0.96 Fe0.85 Na0.063 (N ¼ 14); AMOS: Mg1.00 Fe0.89 Na0.044 (N ¼ 5) [26]; Mg1.00 Fe0.90 Na0.060, Ca/Fe ¼ 0.04  0.02, chondritic [2]. Tensile strength: 60% of photographed meteors show end flare, from which S ¼ 4e18 kPa [2]. Age: Likely 1700 or 3800 years [2,3] Source: 2021 HK12 duncertain Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Epoch 2021-Jul-01.0 TDB 3.284 1.036 0.684 47.0 168.8 187.1 355.9 Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number detected: Peak ZHR: Magn. distribution index:

Brief history: Rich in fireballs with multiple flares (e.g., Fig. 5.11). Shower is episodic with a 7-year period, first confirmed by [1], after [2] noticed. We find here 7.078  0.019 year (within 0.79 to þ0.54 years from the mean, or dust spread over w19% of orbit), which corresponds to a ¼ 3.687  0.019 AU and equal to the 5:3 mean-motion resonance with Jupiter (a ¼ 3.700 AU). First seen as slow-moving, short and bright meteors at 10e12 per hour on August 21e25, 1879 by [4,5] from R.A. ¼ 291 , Decl. ¼ þ60 , called “o-Draconids,” and again in 1893 called “qCygnids” [6]. Less certain accounts from Tupman in 1871 and Corder in 1877. In 1893, reports of fireballs. High rates in 1901 [7,8]. In 1922, radiant active between August 15 and 26 [9]. 1929 return produced “exploding fireFIG 5.11 k-Cygnid [27]. balls” [11]. First photographed orbit by [12,13] in 1950 and by [14] in 1957. 1978 outburst recorded visually by C. Johannink. The 1985 and 1993 outbursts were captured by the DMS small camera program [15,23], and observed by the author [16]. 2007 outburst recorded by the Spanish Fireball Network, amongst others [2]. 2020 and 2021 returns were recorded visually [10], by low-light video cameras and radar, with a peak on August 13, so maximum shifting by about 0.35 /year. From photographed orbits up to 1994, [14] distinguished in addition to the kappa Cygnids also the “Alpha Lyrids” (southern part of #12), “Zeta Draconids” (¼ #197) and “August Lyrids” (southern part of #197). [23] grouped radiants into 7 showers. Consolidation to #12 and #197 by [17]. Further discussion by [20]. Model by [2,18] found nodal line rotated once in 2100 years. Model by [18] proposed 2002 MG1 or 2004 LA12. Model by [3]

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199

September

proposed 2008 ED69, but semimajor axis too low. Model by [28] again pointed to 2002 MG1 (not 2002 LV), but no match with radiant or 7:1 period. 2021 HK12 identified here, H ¼ þ17.6 magnitude object, in line with trend in orbital elements of the encountered steam. Name and number by [13], said to follow [12,22], therefore name may go back to [6]. References: [1] Koseki M. (2014) JIMO 42, 89e89/181e197; [2] Trigo-Rodriguez J., et al. (2008) MNRAS 392, 367e375; [3] Jenniskens P., Vaubaillon J. (2008) AJ 136, 725e730; [4] Denning W. F. (1879) Nature 20, 457e459; [5] Denning W. F. (1881) The Astron. Register 19, 208e208; [6] Denning W. F. (1893) The Observatory 16, 317e319; [7] Besley W. E. (1903) Rep. Meteor Section B.A.A. 11, 196e205; [8] Davidson M. (1914) J. BAA 25, 125e130; [9] Cook A. G. (1923) Memoirs of the B.A.A. 24, 293e326; [10] 26] Miskotte K., et al. (2022) eMeteornews 7, 19e28; [11] King A. (1929) The Observatory 52, 310e314; [12] Jacchia L. G. (1952) Harvard Techn. Rep. No. 10, Cambridge, MA: Harvard Obs., 6 pp; [13] Whipple F. L. (1954) AJ 59, 201e217; [14] Lindblad B. A. (1995) EMP 68, 397e404; [15] Betlem H., et al. (1998) AA Supp. Ser. 128, 179e185; [16] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [17] Jenniskens P., et al. (2016) Icarus 266, 331e354; [18] Jones D. C., et al. (2006) MNRAS 371, 684e694; [19] Jenniskens P. (1994) AA 287, 990e1013; [20] Shiba Y. (2017) JIMO 45, 127e143; [21] Molau S., et al. (2015) JIMO 43, 188e191; [22] Norton A. P. (1943) A Star Atlas. London: Gall and Inglis; [23] Langbroek M. (1993) Radiant, J. of the DMS 15, 96e106; [25] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [26] Matlovic P., et al. (2019) AA 629, A71eA90; [27] Miskotte K. (2020) eMeteorNews 5, 161e177; [28] Moorhead A. V., et al. (2015) AJ 150, 122e135.

Sep. 10 (lo ¼ 167 )

1146 DHO d delta Horologiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density:

Mellish-type shower, toroidal shower, TJ ¼ þ0.71  0.40 Annual shower September 17e27 (lo ¼ 163 e173 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 168.5 60.8 40.0 235.8 59.1 43.6 0.11 þ0.77 0.31 þ0.68 þ0.21 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 13.6 0.907 0.935 74.1 37.4 348.5 25.2 0.0191 0.0900 2.44 3.99 1.98 3.99 0.0080 0.0033 þ0.50 þ1.43 þ1.00 þ2.43 w0.1/h (N ¼ 66, hr ¼ 59.7 , m(Mv ¼ 0) ¼ 0.06 g) 2.52  0.21 (s ¼ 2.00  0.08) I: Hb ¼ 108.0  0.67 Mv; Hmax ¼ 100.3 þ 0.38 Mv; He ¼ 92.0 þ 1.00 Mv (N ¼ 64) I: low F ¼ 0.48, fragile meteoroids I: r  0.71 g/cm3 (a1 ¼ 0.076 km, a2 ¼ 4.06/s), lower if fragile

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

September 16e26 (lo ¼ 162 e172 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 167.2 60.0 40.8 234.5 0.57 þ0.37 þ0.03 a (AU) q (AU) e i ( ) 2.17 0.876 0.600 66.6 0.043 0.154 4.2 0.0017 þ0.0047 þ0.31 N ¼ 856

Age: Source:

From c and s: w26,000 y e

b ( ) 59.2 þ0.18 u ( ) 48.9 10.5 þ0.17

Vg (km/s) 37.5 þ0.19 U ( ) 346.8 2.3 þ1.00

P ( ) 35.8 20.8 þ1.17

Brief history: First reported here from SAAMER radar data and CAMS video data.

eV

e R[S]

200

Allsky: Video and Radar

September

201

Sep. 21 (lo ¼ 179 )

1045 SUT d September upsilon Taurids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2005-Oct-24.0 UT

Long-period comet, TJ ¼ 0.88  0.47 Annual shower with episodic outbursts 2014, 2020 September 20e23 (lo ¼ 178.2 e180.2 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 179.12 66.24 þ24.11 249.21 þ2.42 67.8 þ0.78 þ0.04 0.29 þ0.08 0.19 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 30.5 0.6573 0.9899 175.20 252.42 179.3 71.91 eV 0.0173 0.0562 0.62 3.09 0.39 3.09 0.0101 0.0067 þ0.12 þ1.30 þ1.00 þ2.30 w0.9/h (N ¼ 72, hr ¼ 56.2 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.66  0.24 (s ¼ 2.06  0.11) Ia: Hb ¼ 117.4  0.90 Mv; Hmax ¼ 107.2 þ 0.94 Mv; He ¼ 99.3 þ 1.54 Mv (N ¼ 38) Ia: low F ¼ 0.56, fragile Ia: r  0.43 g/cm3 (a1 ¼ 0.0685 km, a2 ¼ 4.25/s), lower if fragile From c and s: w30,000 y; Earth passes through core of stream (sU < su) C/2005 T4 (SWAN) euncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.32 0.649 0.930 160.0 41.4 25.4 66.8

Brief history: Very compact and welldefined shower on top of strong sporadic apex source activity. Low i and moderate q cause rapid rotation of nodal line. First recognized from CAMS and GMN video observations during a modest outburst in 2020 [1] from R.A. ¼ 66.2 , Decl. ¼ þ24.1 and Vg ¼ 67.8 km/s centered on lo ¼ 179.15 . The compact radiant suggests the crossing of a 1-revolution dust trail of a long-period comet, but some meteors are detected from this shower annually. Yearly tally of orbits measured (with increasing number of cameras) starting in 2007: 2, 0, 1, 1, 5, 4, 0, 11, 6, 8, 10, 5, 17, 45, 19. Activity curve shown in Fig. 5.12. Visual observations of “September Taurids” that are mostly from FIG 5.12 ZHR profile. an earlier lo ¼ 168e176 period during 1991e2004 are summarized in [3]. Possible other earlier visual observations of this shower are discussed by [2]. Name and number by [1]. References: [1] Jenniskens P., Cooper T. (2020) CBET 4862. Ed.: D.W.E. Green, Cambridge: CBAT, issued September 28, p. 1e1; [2] Cooper T. (2021) eMeteorNews 6, 255e261; [3] Jenniskens P. (1992) Radiant, Journal of the Dutch Meteor Society 14, 18e130.

202

Allsky: Video and Radar

October

203

Oct. 9 (lo ¼ 197 )

924 SAN d 62 Andromedids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, TJ ¼ þ6.99  0.11 Annual shower October 4e14 (lo ¼ 190 e200 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 196.5 37.9 þ46.3 214.6 þ29.6 16.9 þ1.18 þ0.28 0.01 0.04 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.82 0.395 0.518 20.9 320.7 196.5 157.6 eV 0.0143 0.0196 1.86 1.60 1.69 1.60 0.0008 þ0.0009 þ0.01 þ0.01 þ1.00 þ1.01 w0.1/h (N ¼ 79, hr ¼ 66.3 , m(Mv ¼ 0) ¼ 0.53 g) c ¼ 2.92  0.30 (s ¼ 2.17  0.12) Components have low He, Ke < 79, like III: IIa: Hb ¼ 91.4  0.72 Mv; Hmax ¼ 81.6 þ 0.45 Mv; He ¼ 69.9 þ 3.21 Mv (N ¼ 11) IIb: Hb ¼ 86.9  0.71 Mv; Hmax ¼ 78.6 þ 0.71 Mv; He ¼ 71.3 þ 1.94 Mv (N ¼ 44) F ¼ 0.46: fragile IIa: r  4.4 g/cm3 (a1 ¼ 0.112 km, a2 ¼ 1.82/s), fragile: low a2 IIb: r  5.0 g/cm3 (a1 ¼ 0.036 km, a2 ¼ 3.37/s) dpossibly Na poor/free e 363027 (1998 ST27) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.82 0.385 0.530 21.1 322.5 197.5 160.0

Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2017-Nov-06.0 TDB

Brief history: First reported by [1] with R.A. ¼ 37.9 , Decl. ¼ 46.1 , and Vg ¼ 16.8 km/s around lo ¼ 196.7. Compact shower among short-period orbits. Parent body likely a primitive asteroid. Source 1998 ST27 identified here, has absolute magnitude H ¼ 19.64 magn, w3 h rotation period, diameter of 0.58  0.23 km, and low geometric albedo of 0.059  0.066 (data from NeoWise) [2]. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29; [2] https://ssd.jpl.nasa.gov/ tools/sbdb_lookup.html#/?des¼363027, last accessed 2022 May 25.

204

Allsky: Video and Radar

October

205

206

Allsky: Video and Radar

November

207

Nov. 10 (lo ¼ 228 )

338 OER d omicron Eridanids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.13  0.29 Annual shower September 29eJanuary 31 (lo ¼ 186 e311 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 228.1 56.1 2.2 185.7 20.8 27.8 þ0.60y 0.11y 0.34y 0.28y 0.13y (186e260 ) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.91 0.513 0.865 20.2 92.7 48.1 141.8 eV 0.0482 0.0824 3.31 5.21 26.2 5.21 þ0.0065y 0.0007 þ0.04y 0.83y þ1.00 þ0.17 w0.4/h (N ¼ 5946, hr ¼ 47.4 , m(Mv ¼ 0) ¼ 0.18 g) c ¼ 2.52  0.17 (s ¼ 2.00  0.07) Component Ia has unusually high Kc > 104 and low Ke < 84: Ia: Hb ¼ 108.3  1.73 Mv; Hmax ¼ 90.4 þ 1.63 Mv; He ¼ 83.6 þ 2.25 Mv (N ¼ 119) Ib: Hb ¼ 101.1  1.33 Mv; Hmax ¼ 87.3 þ 1.43 Mv; He ¼ 82.1 þ 1.89 Mv (N ¼ 2936) IIb: Hb ¼ 91.5  0.71 Mv; Hmax ¼ 84.6 þ 0.66 Mv; He ¼ 80.0 þ 1.08 Mv (N ¼ 811) Ia: r w 0.84 g/cm3 (a1 ¼ 0.065 km, a2 ¼ 3.85/s), possibly Na enhanced Ib: r w 1.32  0.14 g/cm3 (a1 ¼ 0.081 km, a2 ¼ 3.20/s) dFe, Na poor IIb: r w 2.5  0.3 g/cm3 (a1 ¼ 0.118 km, a2 ¼ 3.94/s) IIb: Mg1.69 Fe0.78 Na0.070 (N ¼ 2) e 2015 KK duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.56 0.547 0.786 16.4 85.4 56.6 142.1

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2015-May-19.0 TDB

FIG 5.13 ZHR profile.

Brief history: This is a long duration shower with a large change in the radiant position during its activity period. As a result, it was known under several names. Nineteenth century visual observers plotted a radiant at R.A. ¼ 50 , Decl. ¼ 1 in October [5]. First instrumentally detected from SonotaCo low-light video observations in 2007e2008 by [1] with 26 meteors from a radiant at R.A. ¼ 60.7 , Decl ¼ 1.5 , and Vg ¼ 26.9 km/s during lo ¼ 227.9e245.0 . Confirmed from single-station video observations in the IMO Video Network by [2], and from CAMS video observations by [3,4]. Peak ZHR is only an upper limit, with ZHR curve of Fig. 5.13 shifting downward if peak rate is less. Association with 2015 KK suggested here. Name and number by [1].

References: [1] Kanamori T. (2009) JIMO 37, 55e62; [2] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [3] Jenniskens P., et al. (2011) Icarus 216, 40e61; [4] Jenniskens P., et al. (2016) Icarus 266, 331e354. [5] Heis E., Neumayer G. (1867) On Meteors in the Southern Hemisphere. Mannheim: J. Schneider, 25pp (p. 15).

208

Allsky: Video and Radar

209

November

Nov. 5 (lo ¼ 222 )

779 OLV d October lambda Velids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ þ6.32  0.58 Annual shower, part of a ¼ 0.86 AU, i ¼ 60 group November 1e9 (lo ¼ 218 e226 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 221.8 134.6 37.9 291.4 51.6 30.0 þ0.28 0.17 0.43 þ0.06 0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) 0.88 0.621 0.290 61.1 225.4 41.8 0.0871 0.0802 4.26 15.04 2.13 0.0035 0.0004 þ0.03 1.28 þ1.00 0.99 0.762 0.231 68.0 256.3 41.0 N ¼ 2104 (m(Mv ¼ 0) ¼ 0.15 g) c ¼ 4.64  0.47 (s ¼ 2.67  0.11) IIa: r ¼ 1.4 g/cm3 (a1 ¼ 0.085 m, a2 ¼ 5.05/s) e e

eR

P ( ) 267.6 15.04 0.28 297.3

e R[S] e R[1] eV eV

Brief history: Part of Puppids-Pyxidids Complex (with #773 and 777). Also part of a group that includes #402, 405, 760, 763, 773, 777, and 779 (a ¼ 0.79e0.94 AU, i ¼ 57e62 , smooth change of uei). Shower First described from SAAMER radar observations by [1] with 163 meteors radiating from R.A. ¼ 132.8 , Decl. ¼ 38.1 , Vg ¼ 33.9 km/s around lo ¼ 221.0 . Tentative detection from CAMS video data here (N ¼ 150, but only N ¼ 10 at q w 0.69 AU). Name and number by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182. Nov. 5 (lo ¼ 222 )

780 NPU d November Puppids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number measured: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or Mellish type shower, toroidal, TJ ¼ þ3.68  0.63 Annual shower November 1e9 (lo ¼ 218 e226 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 222.4 119.8 41.5 274.7 59.8 37.9 þ0.41 0.15 0.30 0.02 0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.55 0.979 0.375 70.9 352.1 42.4 34.2 0.0251 0.167 2.84 22.67 2.15 22.67 þ0.0004 0.0007 0.27 þ0.38 þ1.00 þ1.38 1.17 0.961 0.176 69.2 322.6 44.0 6.6 N ¼ 2554 (m(Mv ¼ 0) ¼ 0.09 g) e IIa: r ¼ 0.8e3.9 g/cm3 e e

eR

e R[S] e R[1]

Brief history: First described from SAAMER radar observations by [1] with 451 meteors radiating from R.A. ¼ 125.1 , Decl. ¼ 40.5 , Vg ¼ 35.4 km/s around lo ¼ 224.0 . Perhaps related to #781. Name and number by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182.

210

Allsky: Video and Radar

211

November

Dec. 15 (lo ¼ 264 )

610 SGM d 68 Geminids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Asteroid, Phaethon Complex, TJ ¼ þ3.29  0.50 Annual shower November 28eDecember 31 (lo ¼ 246 e279 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 263.6 112.8 þ13.1 208.8 8.5 38.2 þ0.93 0.15 0.06 þ0.03 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.72 0.101 0.943 25.0 148.3 84.0 231.2 eV 0.0339 0.022 6.03 5.59 8.36 5.59 þ0.0033 þ0.0001 0.10 0.08 þ1.00 þ0.92 w0.3/h (N ¼ 1236, hr ¼ 51.5 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.10  0.02 (s ¼ 1.81  0.01) Component II has low He, Ke < 79, like III: IIa: Hb ¼ 99.7  1.23 Mv; Hmax ¼ 90.8 þ 0.60 Mv; He ¼ 85.0 þ 1.38 Mv (N ¼ 337) IIb: Hb ¼ 93.7  1.02 Mv; Hmax ¼ 88.2 þ 0.53 Mv; He ¼ 83.9 þ 1.04 Mv (N ¼ 307) IIa: r w 1.6 g/cm3 (a1 ¼ 0.050 km, a2 ¼ 6.69/s) dpossibly Na poor IIb: r w 2.9 g/cm3 (a1 ¼ 0.028 km, a2 ¼ 9.12/s) dpossibly Na free From c: 11,000 y e

Meteoroid density: Age: Source:

Brief history: First identified by [1] from 28 meteors spread over 14 days detected by the Croatian Meteor Network and the SonotaCo network from R.A. ¼ 112.5 , Decl. ¼ þ13.6 and Vg ¼ 40.7 km/s around lo ¼ 263.0 Same shower detected by [2,3], but called #253 (see p. 647). Name and number by [1]. References: [1] Segon D., et al. (2014) JIMO 42, 227e233; [2] Jenniskens P., et al. (2016) Icarus 266, 331e354; [3] Jenniskens P., et al. (2018) PSS 154, 21e29. Nov. 14 (lo ¼ 232 )

781 NLV e November lambda Velids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, toroidal, TJ ¼ +2.91  0.30 Annual shower November 9 e 18 (lo ¼ 227 e 236 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 232.4 119.4 44.1 268.7 61.2 38.0 þ0.95 0.23 þ0.54 þ0.07 0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.99 0.980 0.515 69.9 4.9 52.3 56.1 0.0145 0.108 5.32 16.74 2.38 16.74 þ0.0007 0.0071 0.08 1.09 þ1.00 0.09 N ¼ 118 (hr ¼ 58.0 , m(Mv¼0) ¼ 0.08 g) c ¼ 4.24  0.28 (s ¼ 2.57  0.07) II: Hb ¼ 97.3 þ 0.10 Mv; Hmax ¼ 90.4 þ 1.33 Mv; He ¼ 86.4 þ 1.15 Mv (N ¼ 118) II: r w 2.3 g/cm3 (a1 ¼ 0.0305 km, a2 ¼ 6.78 /s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

November 9 e 25 (lo ¼ 227 e 243 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 236.5 124.2 44.6 270.5 þ0.68 0.19 0.09 a (AU) q (AU) e i ( ) 1.76 0.982 0.446 70.6 0.0118 0.179 4.77 0.0004 0.0015 þ0.11 1.28 0.941 0.265 69.9 N ¼ 8,206

Age: Source:

-.-.-

b ( ) 61.3 þ0.06 u ( ) 0.8 15.72 0.18 320.2

Vg (km/s) 38.6 þ0.07 U ( ) 56.5 3.84 þ1.00 52.0

P ( ) 56.9 15.72 þ0.82 12.2

eV

e R[S] e R[1]

212

Allsky: Video and Radar

213

December

Brief history: First described from SAAMER radar observations by [1] with 256 meteors radiating from R.A. ¼ 132.9 , Decl. ¼ 43.8 , Vg ¼ 36.5 km/s around lo ¼ 232.0 . Perhaps related to #780. Name and number by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182. Dec. 5 (lo ¼ 253 )

908 XXL d xi2 Librids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2015-May-19.0 TDB Source: Epoch 2015-May-19.0 TDB

Mellish-type shower, sunskirter, TJ ¼ þ0.77  0.74 Annual shower November 29eDecember 14 (lo ¼ 247 e262 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 253.3 221.7 10.8 329.6 þ5.1 þ0.61 0.23 0.36 0.04 a (AU) q (AU) e i ( ) u ( ) 6.41 0.033 0.996 30.8 20.6 0.0098 0.0053 7.47 3.02 0.0021 0.0002 þ0.87 0.74 ZHR w 0.6/h (N ¼ 18, hr ¼ 4.4 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ w 2.12 (s w 1.81) IIb: Hb ¼ 97.8 þ 0.87 Mv; He ¼ 90.3 þ 2.38 Mv (N ¼ 3) r w 0.4e3.9 g/cm3 From c: w1000 y C/2003 H6 (SOHO) a (AU) q (AU) E i ( ) u ( ) N 0.026 (1.000) 27.1 80.7 C/2003 H7 (SOHO) N 0.027 (1.000) 27.9 82.6

Vg (km/s) 47.0 þ0.05 U ( ) 253.6 3.71 þ1.00

P ( ) 274.4 3.02 þ0.26

eV

duncertain due to low N duncertain U ( ) P ( ) 243.5 324.2 duncertain 242.7 325.3

Brief history: Shower with very low perihelion distance, observed with high zenithdistance of the radiant. Mainly detected by the SonotaCo network (N ¼ 8) and EDMOND/ CMN (N ¼ 7), with CAMS only adding 3 meteors, and no additional meteors detected in 2020 and 2021. Identified as a shower by [1] with R.A. ¼ 223.0 , Decl. ¼ 10.6 and Vg ¼ 42.3 km/s around lo ¼ 254.4 . Shower #1147 is in the same direction, but this shower has a lower entry speed. Name and number by [1]. Fig. 5.14 shows the December sky in HAPLAR data. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

FIG 5.14

Geminids in MU Radar observations.

214

Allsky: Video and Radar

December

215

Dec. 30 (lo ¼ 278 )

1147 NLI d Northern Librids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, possible part of Phaethon Complex, TJ ¼ þ2.91  0.36 Annual shower December 17eJanuary 12 (lo ¼ 265 e291 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 277.8 247.0 16.1 329.0 þ5.4 41.2 þ0.95 0.22 0.06 0.07 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.95 0.054 0.971 23.9 23.4 277.8 304.3 eV 0.0140 0.0061 7.09 3.33 7.48 3.33 0.0006 þ0.0002 0.23 0.14 þ1.00 þ0.86 w0.08/h (N ¼ 22, hr ¼ 15.3 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.48  0.12 (s ¼ 1.99  0.05) Component II has high end height, Ke > 82, perhaps due to entry angle: II: Hb ¼ 100.3 þ 0.05 Mv; Hmax ¼ 94.5 þ 1.97 Mv; He ¼ 90.7 þ 2.97 Mv (N ¼ 10) II: F ¼ 0.60 II: r  1.4 g/cm3 (a1 ¼ 0.095 km, a2 ¼ 5.17/s) duncertain due to low N From c: 5000 y e

Lightcurve shape: Meteoroid density: Age: Source:

Brief history: Shower with same radiant as #908, but lower entry speed and concentrated in later period of activity. Large range in inclination. Helion counterpart to anthelion shower #644. First described here. Dec. 30 (lo ¼ 277 )

1148 SLI d Southern Librids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Jupiter-family comet, possible part of Phaethon Complex, TJ ¼ þ2.82  0.65 Annual shower November 22eJanuary 22 (lo ¼ 240 e299 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 276.5 235.2 26.3 328.8 6.1 41.4 þ1.02 0.23 0.04 0.02 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.02 0.057 0.971 25.9 204.1 90.9 295.0 eV 0.0169 0.0126 7.12 3.86 20.53 3.86 0.0002 þ0.0001 þ0.16 0.04 þ1.00 þ0.96 e (N ¼ 46, hr ¼ 14.6 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 3.55  0.14 (s ¼ 2.38  0.04) IIa: Hb ¼ 102.5  1.60 Mv; Hmax ¼ 96.7  0.51 Mv; He ¼ 92.8  0.13 Mv (N ¼ 23) IIa: F ¼ 0.60 IIa: r w 3.0 g/cm3 (a1 ¼ 0.076 km, a2 ¼ 3.04/s) duncertain due to low N From c: 8000 y e

Brief history: First described here. Helion counterpart to anthelion shower # 610.

216

Allsky: Video and Radar

217

January

Dec. 29 (lo ¼ 277 )

785 TCD d theta Carinids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, TJ ¼ þ1.96  0.59 Annual shower December 23eJan. 1 (lo ¼ 272 e281 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 277.3 159.3 56.1 278.6 56.9 45.4 þ0.82 0.26 0.04 þ0.12 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.92 0.972 0.668 80.9 346.1 97.3 83.1 eV 0.0056 0.107 1.91 3.60 2.28 3.60 0.0001 0.0043 þ0.13 0.08 þ1.00 þ0.92 w0.1/h (N ¼ 43, hr ¼ 54.5  , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 2.41  0.24 (s ¼ 1.96  0.11) II: Hb ¼ 100.6  0.98 Mv; Hmax ¼ 93.0 þ 0.50 Mv; He ¼ 88.1 þ 1.08 Mv (N ¼ 41) II: r w 1.9 g/cm3 (a1 ¼ 0.031 km, a2 ¼ 10.95/s) duncertain due to low N

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

December 24eJanuary 1 (lo ¼ 273 e281 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 277.2 159.8 59.1 283.4 þ0.63 0.18 0.27 a (AU) q (AU) e i ( ) 2.08 0.960 0.543 75.3 0.0163 0.169 4.21 þ0.0004 0.0002 þ0.20 2.38 0.966 0.595 74.5 N ¼ 1948

b ( ) 59.1 þ0.11 u ( ) 338.5 7.63 þ0.32 342.2

Vg (km/s) 41.7 þ0.09 U ( ) 97.2 1.80 þ1.00 96.0

P ( ) 75.8 7.63 þ1.28 78.2

e R[S] e R[3]

Brief history: First identified by [1] from SAAMER radar observations (Fig. 5.15) from R.A. ¼ 156.8 , Decl. ¼ 59.2 and Vg ¼ 41.7 km/s around lo ¼ 276 . Video data now show that this shower overlays shower #314, but has lower Vg. Name and number by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182.

FIG 5.15

SAAMER radar map.

218

Allsky: Video and Radar

219

January

Jan. 6 (lo ¼ 286 )

1183 JMH d January mu Hydrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, evolved stream, TJ ¼ þ2.93  0.45 Annual shower December 22eJan. 20 (lo ¼ 270 e310 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 285.8 157.7 19.5 241.4 27.1 53.1 þ0.99 0.82 þ0.32 0.36 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.58 0.444 0.705 114.5 109.9 105.8 216.2 eV 0.0756 0.059 3.19 9.52 10.38 9.52 þ0.0107 0.0066 0.29 1.17 þ1.00 0.17 w0.3/h (N ¼ 320, hr ¼ 39.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 4.21  0.31 (s ¼ 2.56  0.08) Ib: Hb ¼ 108.1  0.80 Mv; Hmax ¼ 98.9 þ 0.93 Mv; He ¼ 94.1 þ 1.33 Mv (N ¼ 267) III: Hb ¼ 97.4  0.69 Mv; Hmax ¼ 92.8  0.17 Mv; He ¼ 91.1  0.17 Mv (N ¼ 6) Ib: r w 1.06  0.09 g/cm3 (a1 ¼ 0.024 km, a2 ¼ 8.51/s) III: r w 2.2 g/cm3 (a1 ¼ 0.041 km, a2 ¼ 6.66/s) dlikely Na poor/free e

Meteoroid density: Age:

Brief history: First reported here. Lower velocity shower than nearby #569. Very unusual short semi-major axis for highly inclined retrograde orbit. Detected by CAMS, SonotaCo, EDMOND, and GMN networks. There appears to be a bridge linking this shower to #569 (see Fig. 5.16), so this could be considered a shower component. Name and number here. Brief history: First reported here. At position of shower #789. Larger entry speed.

FIG 5.16

#1183 in relation to #569.

Jan. 18 (lo ¼ 298 )

1184 RHC d rho Centaurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.52  0.72 Annual shower January 6e20 (lo ¼ 286 e310 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 297.8 179.0 53.6 269.0 48.4 54.2 þ1.10 0.51 þ0.25 0.02 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.30 0.983 0.865 98.0 1.6 117.8 120.6 eV 0.0022 0.130 3.14 4.55 3.56 4.55 þ0.0003 þ0.0037 þ0.02 0.50 þ1.00 þ0.50 w0.3/h (N ¼ 104, hr ¼ 53.8 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.21  0.25 (s ¼ 2.27  0.09) I: Hb ¼ 112.9  2.18 Mv; Hmax ¼ 103.3  0.01 Mv; He ¼ 97.0 þ 0.88 Mv (N ¼ 72) II: Hb ¼ 101.8  1.69 Mv; Hmax ¼ 93.0 þ 0.80 Mv; He ¼ 88.9 þ 0.55 Mv (N ¼ 30) I: r w 0.53 g/cm3 (a1 ¼ 0.0725 km, a2 ¼ 8.01/s) II: r w 2.7 g/cm3 (a1 ¼ 0.082 km, a2 ¼ 3.27/s) dpossibly Na poor/free From c and s: w80,000 y

Meteoroid density: Age:

220

Allsky: Video and Radar

221

January

Jan. 8 (lo ¼ 288 )

789 JMV d January mu Velids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Meteoroid density: Source:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ þ6.45  0.41 Annual shower January 1e17 (lo ¼ 280 e297 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 288.4 167.4 51.4 269.2 50.2 33.4 þ0.85 0.29 0.05 þ0.09 þ0.23 a (AU) q (AU) e i ( ) u ( ) U ( ) 0.83 0.681 0.184 70.7 175.0 108.4 0.0992 0.0714 4.38 10.6 3.40 þ0.0055 0.0038 þ0.48 0.43 þ1.00 0.88 0.779 0.117 73.1 172.4 107.0 N ¼ 1114 (m(Mv ¼ 0) ¼ 0.11 g) r w 0.8e3.9 g/cm3 e

eR

P ( ) 282.8 10.6 þ0.57 279.4

e R[S] e R[1]

Brief history: First identified by [1] from SAAMER radar observations from R.A. ¼ 166.0 , Decl. ¼ 51.1 and Vg ¼ 34.9 km/s around lo ¼ 287 . Actual semi-major axis may be higher than measured. Name and number by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182. Jan. 10 (lo ¼ 290 )

790 PVL e psi Velids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Lightcurve:

Jupiter-family comet, toroidal shower, TJ ¼ þ2.83  0.42 Annual shower December 29 e Jan. 18 (lo ¼ 278 e 298 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 289.5 143.6 45.1 241.1 54.2 41.6 þ0.70 0.31 þ0.00 þ0.02 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.02 0.840 0.583 75.0 52.2 109.5 159.4 eV 0.0258 0.0609 2.96 5.73 5.26 5.73 0.0003 0.0024 0.04 þ0.19 þ1.00 þ1.19 N ¼ 41 (hr ¼ 62.3 , m(Mv¼0) ¼ 0.07 g) c ¼ 3.35  0.42 (s ¼ 2.31  0.15) Ib: Hb ¼ 104.9  1.07 Mv; Hmax ¼ 92.2 þ 1.39 Mv; He ¼ 89.5 þ 1.41 Mv (N ¼ 12) IIIb: Hb ¼ 92.3 þ 0.41 Mv; Hmax ¼ 89.2 þ 0.51 Mv; He ¼ 84.1 þ 1.04 Mv (N ¼ 27) Ib: r w 0.76 g/cm3 (a1 ¼ 0.037 km, a2 ¼ 9.78 /s) euncertain due to low N IIIb: r w 2.5 g/cm3 (a1 ¼ 0.0255 km, a2 ¼ 15.29 /s)

Meteoroid density: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

January 1 e 17 (lo ¼ 281 e 297 ) lo ( ) R.A. ( ) Decl. ( ) 289.9 146.5 44.4 þ0.88 0.37 a (AU) q (AU) e 1.74 0.822 0.527 0.0306 0.112 þ0.0019 þ0.0012 2.00 0.813 0.594 N ¼ 1,544

l ( ) 242.1 þ0.24 i ( ) 75.8 3.83 0.24 75.0

b ( ) 53.1 þ0.03 u ( ) 58.2 8.92 0.42 57.6

Vg (km/s) 41.3 þ0.12 U ( ) 109.8 4.08 þ1.00 108.0

P ( ) 167.8 8.92 þ0.58 165.6

e R[S] e R[1]

Brief history: First identified by [1] from SAAMER radar observations from R.A. ¼ 142.6 , Decl. ¼ 42.6 and Vg ¼ 41.7 km/s around lo ¼ 288 . Video detection here. Name and number by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182.

222

Allsky: Video and Radar

223

January

Dec. 24 (lo ¼ 272 )

1190 JZL d January zeta Leonids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

Jupiter-family comet or asteroid, sunskirter, TJ ¼ þ4.75  0.58 Episodic shower 2014 December 7eJanuary 1 (lo ¼ 280.8 e281.4 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 281.2 155.8 þ24.6 227.5 þ13.1 46.0 e e e e e a (AU) q (AU) e i ( ) u ( ) U ( ) 1.07 0.065 0.942 104.0 337.4 281.17 0.007 0.006 4.1 2.1 0.16 e e e e e N ¼ 14 (m(Mv ¼ 0) ¼ 0.05 g)

eR

P ( ) 258.5 2.2 e

e R[MU]

Brief history: First identified here from MU Radar observations [1] made in 2014. Unusual short-semi major axis orbit for a retrograde moving stream. Related to shower #319, with a continuum in entry speed, perihelion distance and eccentricity versus Sun-centered ecliptic longitude (Fig. 5.17). q is close to the lower limit where meteoroids can survive the heat of the Sun. Name and number here. References: [1] Nakamura T., Yamamoto M., Tanaka Y., Kero J., Szasz C., Watanabe J.-I., Abe S., Kastinen D. (2012) 40th COSPAR Scientific Assembly. Held 2e10 August 2014, Moscow, Russia. Abstract id. C0.3-7-14.

FIG 5.17

Comparing #319 and #1190.

Feb. 10 (lo ¼ 321 )

1191 EIV d 80 Virginids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.64  0.52 Annual shower February 6e14 (lo ¼ 317 e325 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 321.4 206.0 3.7 243.9 þ6.7 67.0 þ0.83 0.34 0.10 0.02 0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 43.9 0.522 0.988 165.4 267.5 321.4 228.5 0.0261 0.0813 0.77 4.73 1.52 4.73 0.0045 0.0052 þ0.00 þ0.67 þ1.00 þ1.67 w0.12/h (N ¼ 45, hr ¼ 40.0 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.84  0.28 (s ¼ 2.13  0.10) Ib: Hb ¼ 112.3  1.36 Mv; Hmax ¼ 101.8 þ 1.41 Mv; He ¼ 97.7 þ 1.52 Mv (N ¼ 29) Ib: r w 0.94 g/cm3 (a1 ¼ 0.012 km, a2 ¼ 18.75/s) From c and s: w32,000 y; From model: rapid rotation of nodal line e

Brief history: First reported here. Nodal line rotates rapidly.

[see plate on p. 406]

eV

224

Allsky: Video and Radar

January

225

226

Allsky: Video and Radar

6 LYRdApril Lyrids

C H A P T E R

6

Northern apex

Atlas of Earth's Meteor Showers https://doi.org/10.1016/B978-0-323-88447-1.00014-4

227

© 2024 Elsevier Inc. All rights reserved.

228

Northern apex

March

March 8 (lo ¼ 347 )

859 MTB d March 12 Bootids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.64  0.24 Annual shower February 22eMarch 17 (lo ¼ 334 e356 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 346.8 214.6 þ25.6 214.9 þ36.8 46.0 þ0.69 0.36 0.11 0.07 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 14.6 0.477 0.968 72.2 273.5 346.8 260.5 0.0338 0.0323 1.65 4.20 5.06 4.20 0.0015 0.0008 0.17 þ0.22 þ1.00 þ1.22 w0.04/h (N ¼ 177, hr ¼ 58.1 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 2.31  0.18 (s ¼ 1.91  0.08) Ib: Hb ¼ 105.7  0.91 Mv; Hmax ¼ 94.0 þ 1.75 Mv; He ¼ 88.2 þ 2.26 Mv (N ¼ 66) II: Hb ¼ 101.0  1.04 Mv; He ¼ 93.6 þ 0.01 Mv; Hmax ¼ 88.3 þ 0.58 Mv (N ¼ 7) III: Hb ¼ 96.0 þ 0.50 Mv; He ¼ 90.5 þ 1.02 Mv; Hmax ¼ 85.9 þ 1.21 Mv (N ¼ 10) Ib: r w 2.4 g/cm3 (a1 ¼ 0.025 km, a2 ¼ 6.30/s) From c and s: w14,000 y e

Meteoroid density: Age: Source:

229

eV

Brief history: Shower discovered by [1] from R.A. ¼ 212.6 , Decl. ¼ þ26.6 with Vg ¼ 46.5 km/s around lo ¼ 344.1 . Number and name assigned by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

March 4 (lo ¼ 343 )

1105 UPV d upsilon Virginids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long period comet; TJ ¼ 0.25  0.45 Annual shower 2011? (N ¼ 3, lo ¼ 343.44e343.49 ) March 1e5 (lo ¼ 340 e345 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 343.4 213.5 3.6 229.2 þ9.2 59.6 þ0.66 0.26 0.28 þ0.00 þ0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 32.0 0.170 0.995 147.3 311.6 343.4 294.6 0.0135 0.0137 1.23 2.93 0.99 2.93 0.0040 þ0.0012 0.31 þ0.53 þ1.00 þ1.54 w0.06/h (N ¼ 20, hr ¼ 37.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.28  0.21 (s ¼ 1.90  0.10) Ib: Hb ¼ 110.7  2.03 Mv; Hmax ¼ 100.4 þ 0.32 Mv; He ¼ 94.5 þ 0.88 Mv (N ¼ 16) Ib: r w 0.83 g/cm3 (a1 ¼ 0.139 km, a2 ¼ 3.60/s) From c and s: w5700 y; Earth passing through core of stream (sU < su) e

eV

Brief history: Minor shower based on 16 CAMS triangulated meteors, three from the SonotaCo network and one from EDMOND. Number and name assigned here.

230

Northern apex

March

231

March 6 (lo ¼ 345 )

345 FHE d f Herculids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, toroidal shower, TJ ¼ þ1.15  0.60 Annual shower February 14eMarch 22 (lo ¼ 325 e361 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 344.6 267.1 þ37.7 281.8 þ60.6 44.6 þ0.73 0.00 þ0.19 þ0.02 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.93 0.978 0.836 76.9 165.6 344.7 149.8 eV 0.0274 0.171 6.46 12.1 9.72 12.1 0.0002 þ0.0001 0.04 0.24 þ1.00 þ0.78 w0.7/h; 1.9/h [1] (N ¼ 1816, hr ¼ 50.7 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.69  0.04 (s ¼ 2.08  0.02) Ib: Hb ¼ 106.5  1.25 Mv; Hmax ¼ 98.1 þ 0.37 Mv; He ¼ 93.1 þ 0.76 Mv (N ¼ 709) IIb: Hb ¼ 96.2  0.80 Mv; Hmax ¼ 90.9 þ 0.05 Mv; He ¼ 86.1 þ 0.26 Mv (N ¼ 317) Ib: r w 0.88  0.52 g/cm3 (a1 ¼ 0.060 km, a2 ¼ 5.38/s) IIb: r w 1.7  0.7 g/cm3 (a1 ¼ 0.064 km, a2 ¼ 6.94/s) dpossibly Na free From c and s: w65,000 y e

Meteoroid density: Age: Source:

Brief history: Shower orbital elements first reported from single station IMO video meteor network data by [1] with R.A. ¼ 268 , Decl. ¼ 41 and Vg ¼ 44 km/s around lo ¼ 346 . Shower confirmed from triangulated meteors by [2]. Core of shower just outside Earth orbit forms a complex with #40 and 409. Set extracted here may represent two showers, for lo < 341 and lo > 341 . Name and number by [1]. References: [1] Molau S., Kac J. (2009) JIMO 37, 92e93; [2] Jenniskens P., et al. (2016) Icarus 266, 384e409. February 26 (lo ¼ 338 )

712 FDC d February delta Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter family comet; TJ ¼ þ2.16  0.28 Annual shower February 17eMarch 14 (lo ¼ 327 e353 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 338.3 291.4 þ48.4 332.6 þ68.1 31.0 þ1.23 þ0.04 1.04 0.30 0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.69 0.909 0.754 49.0 144.1 338.2 124.6 0.0224 0.0869 4.47 5.60 5.94 5.60 0.0025 þ0.0023 0.35 0.62 þ1.00 þ0.38 w0.5/h (N ¼ 341, hr ¼ 40.7 , m(Mv ¼ 0) ¼ 0.14 g) c ¼ 2.85  0.04 (s ¼ 2.14  0.02) Ib: Hb ¼ 101.8  0.92 Mv; Hmax ¼ 91.5 þ 0.90 Mv; He ¼ 86.1 þ 1.53 Mv (N ¼ 162) III: Hb ¼ 90.5 þ 0.02 Mv; Hmax ¼ 84.9 þ 1.66 Mv; He ¼ 79.4 þ 2.42 Mv (N ¼ 24) Ib: r w 1.4  0.5 g/cm3 (a1 ¼ 0.089 km, a2 ¼ 2.94/s) III: Possibly Na poor/free e e

Meteoroid density: Age: Source:

eV

Brief history: Shower orbital elements first reported by [1] from R.A. ¼ 288.8 , Decl. ¼ þ46.8 and Vg ¼ 32.0 km/s around lo ¼ 339.0 . Shower #734 [1] forms part of same structure in P-i diagram and is included here. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

232

Northern apex

233

March

March 20 (lo ¼ 359 )

1052 CAQ d chi Aquilids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2004-Oct-08.0 TDB

Long period comet; TJ ¼ 0.07  0.51 Annual shower March 15e25 (lo ¼ 354 e4 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 359.0 292.8 þ13.1 298.1 þ34.8 57.5 þ1.02 0.13 þ0.00 þ0.00 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 18.1 0.693 0.964 109.8 112.2 359.0 111.1 eV 0.0293 0.0634 1.97 4.72 2.31 4.72 0.0042 0.0046 0.14 0.64 þ1.00 þ0.29 w0.2/h (N ¼ 79, hr ¼ 36.2 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.57  0.08 (s ¼ 2.02  0.04) Ib: Hb ¼ 110.0  1.09 Mv; Hmax ¼ 101.5 þ 0.50 Mv; He ¼ 96.8 þ 0.99 Mv (N ¼ 39) Ib: r w 0.46  0.30 g/cm3 (a1 ¼ 0.153 km, a2 ¼ 6.19/s) From c and s: w39,000 y C/2004 S1 (Van Ness) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 132,300 0.682 1.000 114.7 92.8 19.2 112.0

Brief history: Early morning shower. Number and name assigned here. March 19 (lo ¼ 358 )

893 EOP d eta Ophiuchids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 1.01  0.74 Annual shower March 12eApril 5 (lo ¼ 351 e16 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 358.0 260.4 16.3 262.8 þ6.8 70.9 þ0.80 0.02 0.22 þ0.01 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 25.0 0.942 0.970 168.2 205.4 357.6 201.9 0.0129 0.133 1.56 4.35 6.47 4.35 0.0027 þ0.0003 0.03 þ0.76 þ1.00 þ1.76 w0.3/h (N ¼ 238, 36.7 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.24  0.08 (s ¼ 2.28  0.03) I: Hb ¼ 115.1  1.72 Mv; Hmax ¼ 106.2 þ 0.35 Mv; He ¼ 101.5 þ 1.04 Mv (N ¼ 152) I: r w 0.89  0.66 g/cm3 (a1 ¼ 0.026 km, a2 ¼ 9.04/s) From c and s: w70,000 y e

e 2021 eV

Brief history: Shower first reported by [1] from a group of 15 triangulated meteors in apex source at R.A. ¼ 260.3 , Decl. ¼ 16.4 with Vg ¼ 71.6 km/s around lo ¼ 358.0 . Maximum activity appears to be skewed toward beginning of activity interval (Fig. 6.1). No known past observations. Source is unknown. Name and number assigned by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

FIG 6.1 ZHR profile (ZHR scale uncertain).

234

Northern apex

235

April

April 8 (lo ¼ 18 )

450 AED d April epsilon Delphinids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.41  0.32 Annual shower April 4e20 (lo ¼ 14 e30 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 18.4 308.1 þ12.3 293.6 þ0.90 þ0.46 þ0.12 a (AU) q (AU) e i ( ) 22.3 0.727 0.967 121.2 0.0304 0.0755 1.84 þ0.0028 þ0.0006 0.40 w0.3/h (N ¼ 245, hr ¼ 33.2 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.44  0.17 (s ¼ 1.97  0.08) Ib: Hb ¼ 110.9  0.81 Mv; Hmax ¼ 100.9 þ 1.23 Mv; Ib: r w 0.76 g/cm3 (a1 ¼ 0.122 km, a2 ¼ 3.55/s) From c and s: w38,000 y e

b ( ) þ29.9 þ0.18 u ( ) 116.1 4.71 þ0.02

Vg (km/s) 60.8 0.11 U ( ) 20.4 3.57 þ1.00

P ( ) 136.6 4.71 þ0.94

eV

He ¼ 96.3 þ 1.66 Mv (N ¼ 106)

Brief history: First reported by [1] from a D-criterion search from R.A. ¼ 307.2 , Decl. ¼ þ11.8 with Vg ¼ 61.5 km/s around lo ¼ 20.2 . Confirmed by [2] from a density enhancement in the apex source background. Name and number by [1]. References: [1] Rudawska R., Jenniskens P. (2014) In: Meteoroids 2013. T. J. Jopek, F. J. M. Rietmeijer, J. Watanabe, I. P. Williams (eds.), A.M. University, Poznán, p. 217e224; [2] Jenniskens P., Nénon Q. (2016) Icarus 266, 371e383. April 8 (lo ¼ 18 )

1054 TDE d 13 Delphinids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1743-Sep-21.1 TDB

Long-period comet, TJ ¼ 0.59  0.38 Annual shower April 5e14 (lo ¼ 15 e24 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 18.4 310.1 þ5.3 295.6 þ22.7 62.9 þ0.96 þ0.31 þ0.09 þ0.04 0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 66.2 0.623 0.991 132.9 103.9 18.4 123.9 eV 0.0234 0.0990 1.07 4.54 2.70 4.54 0.0019 0.0017 0.15 0.29 þ1.00 þ0.71 w0.1/h (N ¼ 39, hr ¼ 30.1 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.39  0.09 (s ¼ 1.95  0.04) I: Hb ¼ 113.8  1.91 Mv; Hmax ¼ 101.5 þ 1.31 Mv; He ¼ 95.9 þ 2.44 Mv (N ¼ 28) I: r w 0.46 g/cm3 (a1 ¼ 0.110 km, a2 ¼ 3.51/s). duncertain due to low N From c and s: w29,000 y; Radiant drift: sU < su C/1743 Q1 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.523 1.000 134.4 119.1 9.6 128.7

Brief history: First reported here.

236

Northern apex

April

237

April 3 (lo ¼ 13 )

27 KSE e kappa Serpentids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type comet, TJ ¼ þ0.88  0.43 Annual shower March 27 e April 10 (lo ¼ 6 e 20 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 13.2 230.7 þ20.4 208.3 þ37.4 42.2 þ0.66 0.28 0.14 0.07 0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.6 0.496 0.957 61.4 271.9 13.2 285.7 eV 0.0459 0.0829 6.13 6.18 3.87 6.18 0.0008 0.0015 0.25 þ0.16 þ1.00 þ1.16 w0.4 /h (N ¼ 374, hr ¼ 56.0 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.97  0.09 (s ¼ 2.18  0.03) Ib: Hb ¼ 105.5  1.03 Mv; Hmax ¼ 95.3 þ 0.74 Mv; He ¼ 90.1 þ 1.08 Mv (N ¼ 142) II: Hb ¼ 98.1  0.55 Mv; Hmax ¼ 88.6 þ 1.24 Mv; He ¼ 82.8 þ 0.66 Mv (N ¼ 50) III: Hb ¼ 91.9 þ 0.15 Mv; Hmax ¼ 88.3 þ 0.00 Mv; He ¼ 84.2 þ 0.36 Mv (N ¼ 65) Ib: r w 0.72 g/cm3 (a1 ¼ 0.160 km, a2 ¼ 4.73 /s) II: r w 2.0 g/cm3 (a1 ¼ 0.140 km, a2 ¼ 3.53 /s) epossibly Na poor epossibly Na free III: r w 1.8 g/cm3 (a1 ¼ 0.115 km, a2 ¼ 7.71 /s) From c and s: w 46,000 y

Meteoroid density:

Age:

Brief history: Name by [1] based on 4 photographed orbits from R.A. ¼ 226e232 , Decl. ¼ þ16e20 (B1950.0) with a spread of 3.3 and speed Vg ¼ 42.0e46.7 km/s during lo ¼ 12e18 . Number assigned by [2]. Listed in [3] as having R.A. ¼ 230.6 , Decl. ¼ þ17.8 . Video data show a diffuse shower with Vg ¼ 38e46 km/s at that time in that direction (see map p. 236). When this source fades, it appears to evolve into a shower with higher entry speed assigned here #699 (see map p. 238). [4] assigned #27 incorrectly to compact #839 at R.A. ¼ 242.1 , Decl. ¼ þ13.9 . References: [1] McCrosky R. E., Posen A. (1959) AJ 64, 25e27; [2] McCrosky R. E., Posen A. (1961) SCoA 4, 15e84; [3] Cook A. F. (1973) NASA SP-319, 183e191; [4] Jenniskens P., et al. (2018) PSS 154, 21e29. April 16 (lo ¼ 26 )

699 OHE e omega Herculids

Dynamic type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.44  0.30 April 8 e 21 (lo ¼ 18 e 30 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 26.3 248.4 þ17.2 216.7 þ38.4 46.5 þ0.73 0.25 0.05 0.09 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 20.0 0.521 0.973 74.8 269.0 26.3 295.3 0.0357 0.0522 2.09 4.81 3.57 4.81 0.0018 0.0003 0.03 þ0.24 þ1.00 þ1.24 < 1 /h (N ¼ 235, hr ¼ 54.8 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 2.46  0.14 (s ¼ 1.98  0.06) Ib: Hb ¼ 107.3  1.38 Mv; Hmax ¼ 96.3 þ 1.26 Mv; He ¼ 90.9 þ 1.72 Mv (N ¼ 93) III: Hb ¼ 94.8  0.67 Mv; Hmax ¼ 89.0 þ 0.91 Mv; He ¼ 85.3 þ 0.63 Mv (N ¼ 21) Ib: r < 1.1 g/cm3 (a1 ¼ 0.058 km, a2 ¼ 2.64 /s), fragmentation: low a2 III: r w 2.9 g/cm3 (a1 ¼ 0.053 km, a2 ¼ 9.90 /s) Na0.078 (N ¼ 1), chondritic From c and s: w 21,000 y

Meteoroid density: Spectroscopy: Age:

Brief history: First isolated from KSE here.

eV

238

Northern apex

April

239

April 9 (lo ¼ 20 )

836 ABH d April beta Herculids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1914-Nov-16.0 TDB Source:

Long-period comet, TJ ¼ þ0.51  0.28 Annual shower April 5e13 (lo ¼ 15 e23 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 19.6 249.5 þ23.1 223.1 þ44.6 47.2 þ0.78 0.49 þ0.14 0.40 þ0.36 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.0 0.662 0.961 78.4 251.7 19.6 271.5 eV 0.0170 0.0538 1.44 2.48 1.62 2.48 0.0041 þ0.0024 þ0.50 þ0.48 þ1.00 þ1.48 w0.01/h (N ¼ 68, hr ¼ 61.7 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 2.10  0.10 (s ¼ 1.81  0.05) Ia: Hb ¼ 107.9  1.35 Mv; Hmax ¼ 96.8 þ 1.56 Mv; He ¼ 91.4 þ 2.29 Mv (N ¼ 35) Ia: r w 0.62 g/cm3 (a1 ¼ 0.052 km, a2 ¼ 5.47/s) duncertain due to low N From c and s: w18,000 y C/1914 S1 (Campbell) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.05 0.678 0.904 76.9 265.3 2.4 267.7 e

Brief history: First reported by [1] from R.A. ¼ 249.7 , Decl. ¼ þ23.0 with Vg ¼ 47.5 km/s around lo ¼ 20.3 . Possible source identified here. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29. April 10 (lo ¼ 20 )

841 DHE d delta Herculids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.38  0.46 Annual shower April 6e14 (lo ¼ 16 e24 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 20.4 256.5 þ23.7 231.7 þ46.3 49.6 þ0.79 0.37 þ0.11 0.27 þ0.26 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 16.2 0.747 0.955 85.6 241.3 20.3 261.3 0.0222 0.0710 1.86 3.68 1.73 3.68 0.0023 þ0.0082 þ0.48 þ0.24 þ1.00 þ1.24 w0.1/h (N ¼ 112, hr ¼ 56.7 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.16  0.16 (s ¼ 1.84  0.08) Fragile, component I has high He: I: Hb ¼ 109.5  0.75 Mv; Hmax ¼ 101.7 þ 0.85 Mv; He ¼ 96.3 þ 1.67 Mv (N ¼ 73) I: low F ¼ 0.59: fragile meteoroids I: r  0.48 g/cm3 (a1 ¼ 0.021 km, a2 ¼ 9.87/s), lower if fragile From c: w15,000; from s (tail): w39,000 y; Earth through core sU < su e

Lightcurve shape: Meteoroid density: Age: Source:

eV

Brief history: First reported by [1] from R.A. ¼ 256.2 , Decl. ¼ þ23.7 with Vg ¼ 49.5 km/s around lo ¼ 19.5 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

240

Northern apex

April

241

April 22 (lo ¼ 32 )

409 NCY d nu Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.69  0.70 Annual shower April 16eMay 1 (lo ¼ 26 e40 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 31.5 308.3 þ41.6 298.2 þ57.1 42.8 þ0.86 þ0.47 þ0.61 0.10 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.66 0.907 0.752 75.6 140.5 31.5 171.0 eV 0.0428 0.120 5.14 8.77 2.75 8.77 þ0.0026 0.0034 0.47 0.71 þ1.00 þ0.29 w2/h (N ¼ 1065, hr ¼ 47.1 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 3.32  0.11 (s ¼ 2.30  0.03) I: Hb ¼ 109.7  1.02 Mv; Hmax ¼ 99.9 þ 0.63 Mv; He ¼ 94.3 þ 1.13 Mv (N ¼ 97) Ib: Hb ¼ 104.8  0.86 Mv; Hmax ¼ 97.0 þ 0.52 Mv; He ¼ 91.4 þ 1.14 Mv (N ¼ 517) II: Hb ¼ 100.8  1.20 Mv; Hmax ¼ 94.4 þ 0.06 Mv; He ¼ 89.6 þ 0.44 Mv (N ¼ 80) III: Hb ¼ 93.6  0.09 Mv; Hmax ¼ 89.6 þ 0.72 Mv; He ¼ 85.8 þ 0.76 Mv (N ¼ 34) I: r w 0.52 g/cm3 (a1 ¼ 0.123 km, a2 ¼ 2.66/s) Ib: r w 0.71 g/cm3 (a1 ¼ 0.040 km, a2 ¼ 5.93/s) dpossibly Na poor II: r w 0.85 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 6.34/s) From c and s: w56,000 y; 50,000 y [3]

Meteoroid density:

Age:

Brief history: First reported by [1] from IMO Video Meteor Network single-station radiant at R.A. ¼ 305.2 , Decl. ¼ þ39.4 with Vg ¼ 42 km/s around lo ¼ 30 . Confirmed by [2] and called “Thatcher’s Ghost”, with nearby shower #348 ARC emerging after lo ¼ 37 . Shower stands out from #40 ZCY in e versus lo diagram (see inset in Map). Model by [3] shows that after 50,000 years of evolution, debris from C/1917 F1 will form a meteor shower at R.A. ¼ 331.4  6.6 , Decl. ¼ þ48.0  3.1 and Vg ¼ 41.3  1.3 km/s around lo ¼ 37.8 . Values lo and Decl. decrease in time, but R.A. increases over 20,000e50,000 year period and does not make a good fit past 50,000 y. References: [1] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [2] Jenniskens P., Haberman B. (2013) JIMO 41, 75e76; [3] Neslusan L., Hajduková M. (2014) AA 566, A33eA41. April 5 (lo ¼ 15 )

40 ZCY d zeta Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.16  0.50 Annual shower March 21eMay 1 (lo ¼ 0 e41 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 15.1 297.1 þ40.3 297.0 þ59.3 43.7 þ0.11 þ0.02 0.20 0.14 þ0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 6.37 0.924 0.856 75.1 146.6 15.2 163.6 eV 0.0347 0.122 5.78 8.72 9.49 8.72 0.0014 þ0.0012 þ0.13 0.40 þ1.00 þ0.60 w2/h (N ¼ 2473, hr ¼ 47.4 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 3.37  0.20 (s ¼ 2.32  0.07) Ib: Hb ¼ 105.0  0.83 Mv; Hmax ¼ 96.7 þ 0.65 Mv; He ¼ 91.1 þ 1.35 Mv (N ¼ 1203) II: Hb ¼ 99.4  0.95 Mv; Hmax ¼ 92.2 þ 0.62 Mv; He ¼ 87.0 þ 0.97 Mv (N ¼ 143) III: Hb ¼ 93.9  0.25 Mv; Hmax ¼ 89.6 þ 0.50 Mv; He ¼ 84.9 þ 0.88 Mv (N ¼ 215) Ib: low F ¼ 0.60, fragile meteoroids Ib: r w 0.68  0.32 g/cm3 (a1 ¼ 0.101 km, a2 ¼ 5.08/s) dNa chondritic II: r w 1.3 g/cm3 (a1 ¼ 0.122 km, a2 ¼ 4.87/s) dperhaps Na poor dperhaps Na free III: r w 2.6  0.7 g/cm3 (a1 ¼ 0.051 km, a2 ¼ 9.02/s) Mg1.09 Fe1.07 Na0.061 (N ¼ 1), chondritic From c and s: w67,000 y

Lightcurve shape: Meteoroid density:

Spectroscopy: Age:

242

Northern apex

243

May

Brief history: Forms a complex with #348 ARC, #409 NCY, and #350 MAL. The long initial activity centered on lo ¼ 15 is called the zeta Cygnids. [1] identified shower #40 from 3 Harvard photographic orbits during lo ¼ 358.4e20.0 with R.A. ¼ 308e319 , Decl. ¼ þ23e32 and Vg ¼ 47e48 km/s. Shower detected in Harvard Meteor Project radar data by [2] from R.A. ¼ 303.8 , Decl. ¼ þ44.8 and Vg ¼ 39.0 km/s around lo ¼ 20 , and called “April Cygnids”. [3] combined these in a Working List candidate shower, but none of the early photographed orbits are a good match to the video-detected shower here [4]. [5] detected #40 from single-station video observations during lo ¼ 7e23 with R.A. ¼ 299.9 , Decl. ¼ þ40.2 and Vg ¼ 43.5 km/s centered on lo ¼ 16 . The new shower #409 was centered on lo ¼ 30 with R.A. ¼ 305.2 , Decl. ¼ þ39.4 and Vg ¼ 42 km/s. Number by [1], name by [3]. References: [1] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [2] Sekanina Z. (1976) Icarus 27, 265e321; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [4] Roggemans P. Cambell-Burns P. (2018) eMeteorNews 3, 175e184; [5] Molau S., Rendtel J. (2009) JIMO 37, 98e121. May 2 (lo ¼ 42 )

350 MAL d May Lacertids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.03  0.38 Annual shower April 27eMay 8 (lo ¼ 37 e48 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 41.7 340.4 þ44.0 322.5 þ47.2 41.7 þ0.84 þ0.50 þ0.15 þ0.09 0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 6.63 0.664 0.902 67.8 106.0 41.7 148.1 eV 0.0547 0.0823 5.49 8.04 3.08 8.04 þ0.0014 þ0.0027 0.10 þ0.22 þ1.00 þ1.22 w0.4/h (N ¼ 114, hr ¼ 32.3 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 3.45  0.09 (s ¼ 2.34  0.03) Ib: Hb ¼ 103.8  1.07 Mv; Hmax ¼ 95.1 þ 0.71 Mv; He ¼ 90.2 þ 1.06 Mv (N ¼ 54) III: Hb ¼ 93.9  0.56 Mv; Hmax ¼ 90.6  0.16 Mv; He ¼ 86.5 þ 0.08 Mv (N ¼ 19) Ib: r w 1.9 g/cm3 (a1 ¼ 0.041 km, a2 ¼ 4.19/s) III: r w 1.9 g/cm3 (a1 ¼ 0.041 km, a2 ¼ 1.94/s) dpossibly Na free

Meteoroid density: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

April 28eMay 8 (lo ¼ 38 e48 ) lo ( ) R.A. ( ) Decl. ( ) 42.3 348.5 þ45.0 þ1.13 þ0.32 a (AU) q (AU) e 6.44 0.676 0.888 0.0795 0.0694 0.0031 þ0.0013 11.1 0.725 0.935 N ¼ 150

Age:

From c and s: w42,000 y

l ( ) 322.2 þ0.25 i ( ) 69.3 2.86 0.08 70.6

b ( ) þ47.6 0.18 u ( ) 107.8 9.41 0.42 114.8

Vg (km/s) 42.1 0.00 U ( ) 42.3 2.61 þ1.00 42.0

P ( ) 151.3 9.41 þ0.58 156.8

e R[M] e R[1]

Brief history: Distinct from #348 ARC: higher Vg and shifted radiant, but forms a complex with #348, #409 and #40. First reported from CMOR radar data by [1] from R.A. ¼ 335.6 , Decl. ¼ þ45.3 and Vg ¼ 43 km/s around lo ¼ 42.0 . Weak detection here from MAARSY data and confirmation from video. Name and number by [1]. References: [1] Brown P., Wong D. K., Weryk R J., Wiegert P. (2010) Icarus 207, 66e81.

244

Northern apex

April

245

April 24 (lo ¼ 34 )

518 AHE d April 102 Herculids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.59  0.43 Annual shower Perhaps 2013 and 2020, both years have higher N over 3 days April 21e26 (lo ¼ 31 e36 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 33.7 271.6 þ19.5 238.5 þ42.9 53.3 þ1.04 þ0.00 þ0.34 þ0.00 þ0.56 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 24.5 0.767 0.967 96.0 238.9 33.7 272.2 eV 0.0172 0.0830 1.57 2.95 1.16 2.95 þ0.0097 þ0.0313 þ0.57 1.79 þ1.00 0.79 w0.05/h (N ¼ 63, hr ¼ 52.6 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 1.92  0.27 (s ¼ 1.71  0.16) Ib: Hb ¼ 109.7  1.06 Mv; Hmax ¼ 100.2 þ 0.88 Mv; He ¼ 95.0 þ 1.63 Mv (N ¼ 26) duncertain due to low N Ib: r w 0.79 g/cm3 (a1 ¼ 0.049 km, a2 ¼ 7.41/s) From c: 3500 y, from s: w32,000 y; Earth through core (sU < su) e

Brief history: Found by [1] from 9 Croatian Meteor Network meteors from R.A. ¼ 273.3 , Decl. ¼ þ18.5 and Vg ¼ 53.6 km/s around lo ¼ 33.8 . Meteors all bright, between 0 and 5 magn. Low magnitude distribution index confirmed here. Number and name assigned by [1]. References: [1] Andreic Z., et al. (2013) JIMO 41, 103e108. April 18 (lo ¼ 28 )

827 NPE d nu Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age:

Long-period comet, TJ ¼ 0.47  0.32 Annual shower April 4eMay 4 (lo ¼ 12 e43 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 27.9 328.5 þ2.5 303.4 þ14.4 61.6 þ0.80 þ0.29 0.12 0.01 þ0.06 a (AU) q (AU) E i ( ) u ( ) U ( ) P ( ) 52.6 0.363 0.993 143.1 74.5 27.9 101.8 0.0309 0.0430 1.66 4.84 6.53 4.84 þ0.0030 0.0003 þ0.14 þ0.33 þ1.00 þ1.38 w0.3/h (N ¼ 243, hr ¼ 25.2 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.45  0.11 (s ¼ 1.97  0.05) I: Hb ¼ 113.0  1.14 Mv; Hmax ¼ 103.1 þ 1.11 Mv; He ¼ 98.3 þ 1.68 Mv (N ¼ 144) I: r w 0.99 g/cm3 (a1 ¼ 0.098 km, a2 ¼ 3.10/s) From c and s: w21,000 y

eV

Brief history: First reported by [1] from R.A. ¼ 329.2 , Decl. ¼ þ2.9 with Vg ¼ 61.8 km/s around lo ¼ 28.9 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

246

Northern apex

247

April

April 29 (lo ¼ 39 )

1058 TPS d 2 Pegasids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1914-Nov-16.0 TDB

Long-period comet, TJ ¼ 0.21  0.67 Annual shower, possibly episodic 2016/2017, 2020 April 28eMay 2 (lo ¼ 38 e42 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 39.3 323.2 þ21.4 294.3 þ33.9 58.7 þ0.76 þ0.43 þ0.34 þ0.00 0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 22.2 0.762 0.967 114.7 119.6 39.3 158.5 eV 0.0198 0.0909 1.51 3.84 1.22 3.84 0.0024 0.0112 0.46 0.78 þ1.00 þ0.22 w0.1/h (N ¼ 31, hr ¼ 30.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.48  0.22 (s ¼ 1.99  0.10) I: Hb ¼ 112.1  1.20 Mv; Hmax ¼ 105.5 þ 0.09 Mv; He ¼ 99.6 þ 1.43 Mv (N ¼ 21) I: low F ¼ 0.56, fragile meteoroids (I component has high He) I: r w 0.32 g/cm3 (a1 ¼ 0.091 km, a2 ¼ 4.80/s) e uncertain due to low N From c and s: w35,000 y; Earth passes through core of stream (sU < su) C/1911 S2 (Quenisset) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 242.4 0.787 0.997 108.1 122.1 36.4 158.5

Source:

e

Brief history: First recognized here.

April 25 (lo ¼ 35 )

1057 SPG d sigma Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.02  0.33 Annual shower, possibly episodic April 17e29 (lo ¼ 27 e39 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 34.9 344.1 þ9.7 314.9 þ0.74 þ0.20 0.22 a (AU) q (AU) e i ( ) 22.7 0.156 0.995 118.3 0.0244 0.0102 3.89 þ0.0014 0.0002 þ0.86 w0.2/h (N ¼ 32, hr ¼ 22.5 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.95  0.23 (s ¼ 2.18  0.08) Ib: Hb ¼ 110.6  0.52 Mv; Hmax ¼ 100.5 þ 1.67 Mv; Ib: r w 0.44 g/cm3 (a1 ¼ 0.362 km, a2 ¼ 3.81/s) From c and s: w11,000 y; high dP/dlo versus i e

Brief history: First recognized here.

b ( ) þ15.1 0.10 u ( ) 46.5 3.98 þ0.19

Vg (km/s) 55.3 þ0.12 U ( ) 34.9 2.98 þ1.00

P ( ) 80.4 3.98 þ1.19

eV

He ¼ 96.7 þ 2.04 Mv (N ¼ 21) duncertain due to low N

248

Northern apex

May

249

May 1 (lo ¼ 40 )

348 ARC d April rho Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.14  0.65 Annual shower April 10eMay 8 (lo ¼ 20 e47 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 40.0 321.6 þ47.3 315.0 þ57.5 40.8 þ0.07 þ0.02 0.07 0.15 þ0.03 a (AU) q (AU) E i ( ) u ( ) U ( ) P ( ) 7.33 0.841 0.886 67.8 130.3 34.7 164.5 eV 0.0278 0.0950 3.31 4.90 7.53 4.90 0.0014 0.0028 þ0.12 0.31 þ1.00 þ0.70 w0.4/h (N ¼ 662, hr ¼ 43.0 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.75  0.06 (s ¼ 2.10  0.02) IIa: Hb ¼ 103.0  0.54 Mv; Hmax ¼ 95.1 þ 0.88 Mv; He ¼ 90.0 þ 1.37 Mv (N ¼ 369) III: Hb ¼ 92.2  0.15 Mv; Hmax ¼ 88.8 þ 0.36 Mv; He ¼ 84.6 þ 0.72 Mv (N ¼ 51) IIa: r w 1.1  0.4 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 4.85/s) III: r w 3.6  1.4 g/cm3 (a1 ¼ 0.051 km, a2 ¼ 4.41/s) dlow a2, possibly Na free 20,000e30,000 y [5]; 30,000e50,000 y [6]; from c and s: w39,000 y C/1917 F1 (Mellish) a (AU) q (AU) E i ( ) u ( ) U ( ) P ( ) 27.4 0.190 0.993 32.7 121.3 88.7 210.0

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

Brief history: First reported from 2002 to 2008 CMOR radar data by [1] from R.A. ¼ 324.5 , Decl. ¼ þ45.9 and Vg ¼ 41.8 km/s around lo ¼ 37.0 . Confirmed as a shower in video data by [2]. Recognized as separate from #409 NCY, by emerging at a different location after April 27 (lo ¼ 37 ) by [7]. Forms a complex with #40 ZCY, #409 NCY, and #350 MAL. Forms a broad activity with shower #40 over much of the activity period, but is isolated in final lo ¼ 40e47 , when it is recognized as a weak visual shower. Discussion on relationship to shower #40 in [3,4]. Model by [5] shows that after 20,000 years of evolution, debris from C/1917 F1 will form a meteor shower from R.A. ¼ 328.8  3.7 , Decl. ¼ þ50.0  2.2 and Vg ¼ 40.9  0.8 km/s around lo ¼ 39.7 . Over time, R.A. increases and Decl. decreases, with best-matched age most likely around 20,000 y. Model by [6] finds best agreement of radiant dispersion for age around 30,000e50,000 y. Name and number by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81; [2] Phillips M., Jenniskens P., Grigsby B. (2011) JIMO 39, 131e136; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Roggemans P., Cambell-Burns P. (2018) eMeteorNews 3, 175e184; [5] Neslusan L., Hajduková M. (2014) AA 566, A33eA41; [6] Neslusan L., Vaubaillon J., Hajduková M. (2016) AA 589, A100eA109; [7] Jenniskens P., Haberman B. (2013) JIMO 41, 75e76.

250

Northern apex

May

May 9 (lo ¼ 49 )

531 GAQ d gamma Aquilids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1853-may-27.0 TDB

Long-period comet, TJ ¼ 0.35  0.43 Annual shower May 2e15 (lo ¼ 42 e55 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 48.7 304.6 þ14.5 262.6 þ33.1 62.4 þ0.91 þ0.24 þ0.10 0.00 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 16.7 0.985 0.941 123.2 198.1 48.7 246.7 0.0183 0.110 1.98 2.40 2.89 2.40 þ0.0010 þ0.0015 þ0.02 0.27 þ1.00 þ0.72 w0.3/h (N ¼ 197, hr ¼ 42.0 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.03  0.19 (s ¼ 2.21  0.07) I: Hb ¼ 112.2  1.02 Mv; Hmax ¼ 104.0 þ 0.93 Mv; He ¼ 97.1 þ 1.49 Mv (N ¼ 113) I: low F ¼ 0.54, fragile meteoroids I: r  0.75 g/cm3 (a1 ¼ 0.103 km, a2 ¼ 4.28/s), lower if fragile Mg1.01 Fe0.99 Na0.061 (N ¼ 1), chondritic From c and s: w59,000 y C/1853 G1 (Schweizer) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 84.8 0.909 0.989 122.2 199.2 43.0 242.2

251

eV

Brief history: First reported by [1] in a parent body search of Croatian Meteor Network video data for meteors associated with comet C/1853 G1, but from a broad distribution of radiants centered on R.A. ¼ 301.8  3.0 , Decl. ¼ þ13.8  2.0 and Vg ¼ 62.7  1.1 km/s around lo ¼ 45 . Shower “questionably identified” by [2]. Confirmed from a more narrow distribution of radiants by [3]. Link with C/1853 G1 by [1]. Model by [4] showed no meteoroids hitting Earth ejected between 3000 BCE and 1500 AD. Model by [5] established link. Name and number by [1]. References: [1] Segon D. (2014) JIMO 42, 57e64; [2] Kornos et al. (2014) In: Meteoroids 2013, T. J. Jopek et al. (eds), A. M. University, Poznan, Poland, p. 225e233; [3] Jenniskens P. (2021) Icarus 365, i.d. 114469; [4] Segon D., et al. (2017) AA 598, A15eA27; [5] Neslusan L., Hajduková M. (2020) MNRAS 498, 1013e1022.

252

Northern apex

May

253

May 17 (lo ¼ 57 )

520 MBC d May beta Capricornids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.63  0.42 Annual shower May 6e31 (lo ¼ 45 e71 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 56.5 303.3 15.3 245.5 þ4.5 66.5 þ0.64 þ0.07 0.24 0.03 0.12 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 23.2 0.574 0.976 170.3 263.0 56.5 319.6 eV 0.082 0.091 1.48 5.68 5.03 5.68 þ0.0074 þ0.0008 þ0.02y þ0.90 þ1.00 þ1.90 w0.4/h (N ¼ 3799, hr ¼ 44.0 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.35  0.05 (s ¼ 2.31  0.02) I: Hb ¼ 115.0  2.08 Mv; Hmax ¼ 103.5 þ 0.84 Mv; He ¼ 98.2 þ 1.34 Mv (N ¼ 224) Ib: Hb ¼ 110.2  1.88 Mv; Hmax ¼ 103.1 þ 0.23 Mv; He ¼ 97.3 þ 0.88 Mv (N ¼ 48) IIb: Hb ¼ 103.4  1.75 Mv; Hmax ¼ 98.7  1.69 Mv; He ¼ 95.5  1.93 Mv (N ¼ 12) I: F ¼ 0.68; Ib: F ¼ 0.55 I: r w 0.37  0.18 g/cm3 (a1 ¼ 0.072 km, a2 ¼ 5.91/s) Ib: r w 0.38 g/cm3 (a1 ¼ 0.519 km, a2 ¼ 9.64/s) dpossibly Na poor dpossibly Na free (low N) IIb: r w 0.8 g/cm3 (a1 ¼ 0.135 km, a2 ¼ 7.10/s) From c and s: w50,000 y

Lightcurve shape: Meteoroid density:

Age:

Brief history: First detected by [1] from 13 orbits measured by the Croatian Meteor Network and the SonotaCo network from R.A. ¼ 303.0 , Decl. ¼ 15.6 and Vg ¼ 65.7 km/ s around lo ¼ 56.8 . Confirmed by [2]. Low inclination causes fast rotation of nodal line. [1] noted similarity to #335 XVI, but covering different activity period. Name and number by [1]. References: [1] Andreic Z., et al. (2013) JIMO 41, 103e108; [2] Jenniskens P., et al. (2016) Icarus 266, 355e370.

254

Northern apex

255

May

May 12 (lo ¼ 52 )

854 PCY d psi Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.85  0.28 Annual shower April 28eMay 20 (lo ¼ 38 e60 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 51.7 297.8 þ53.4 278.9 þ70.9 39.5 þ0.11 þ0.02 0.79 0.02 þ0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 14.7 1.007 0.942 65.9 173.2 51.7 224.5 eV 0.0040 0.0876 2.08 3.24 5.03 3.24 þ0.0008 þ0.0029 þ0.17 þ0.52 þ1.00 þ1.50 w0.2/h (N ¼ 486, 54.8 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.44  0.10 (s ¼ 1.97  0.05) Ib: Hb ¼ 104.4  0.78 Mv; Hmax ¼ 95.9 þ 0.97 Mv; He ¼ 91.3 þ 1.62 Mv (N ¼ 208) III: Hb ¼ 92.5  0.32 Mv; Hmax ¼ 87.7 þ 0.08 Mv; He ¼ 81.1 þ 1.14 Mv (N ¼ 14) Ib: r w 1.4  0.8 g/cm3, I: (a1 ¼ 0.023 km, a2 ¼ 6.99/s) III: r w 2.1 g/cm3, I: (a1 ¼ 0.269 km, a2 ¼ 4.82/s) dNa poor/free Mg0.44 Fe1.01 Na0.040 (N ¼ 1); AMOS: Mg1.00 Fe0.76 Na0.040 (N ¼ 1) [2] From c: w25,000 y, from s (tail) w37,000 y; radiant drift: sU > su e

Meteoroid density: Spectroscopy: Age: Source:

Brief history: Core of shower just outside of Earth’s orbit at lo > 53 . Distinct from #653. First reported from [1] from R.A. ¼ 297.5 , Decl. ¼ þ54.3 and Vg ¼ 39.3 km/s around lo ¼ 53.8 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29; [2] Matlovic P., et al. (2019) AA 629, A71eA90. May 12 (lo ¼ 52 )

661 OTH d 110 Herculids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long period comet, TJ ¼ þ0.20  0.29 Annual shower May 5e16 (lo ¼ 45 e56 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 51.7 280.9 þ21.8 232.8 þ44.8 50.3 þ0.77 0.07 0.00 0.15 þ0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 27.0 0.740 0.971 88.1 242.9 51.7 294.6 eV 0.0235 0.0542 1.66 3.55 2.60 3.55 0.0016 þ0.0040 þ0.24 þ0.15 þ1.00 þ1.15 w0.06/h (N ¼ 67, hr ¼ 59.8 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.59  0.06 (s ¼ 2.03  0.03) Component Ib has low He with Ke < 82: Ib: Hb ¼ 108.0  1.24 Mv; Hmax ¼ 95.4 þ 1.09 Mv; He ¼ 90.4 þ 1.56 Mv (N ¼ 49) duncertain due to low N Ib: r w 0.89 g/cm3 (a1 ¼ 0.028 km, a2 ¼ 7.89/s) From c and s: w38,000 y; high dP/dlo versus i e

Meteoroid density: Age: Source:

[on plate with #520]

Brief history: First identified by [1] from R.A. ¼ 279.0 , Decl. ¼ þ19.7 and Vg ¼ 51.1 km/s around lo ¼ 50.3 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) Plan. Space Sci 154, 21e29.

256

Northern apex

May

257

May 30 (lo ¼ 69 )

668 JMP d June mu Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.35  0.52 Annual shower May 22eJune 6 (lo ¼ 60 e76 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 68.8 342.0 þ23.7 284.7 þ28.7 63.0 þ0.97 þ0.46 þ0.14 þ0.03 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.9 0.887 0.951 128.5 138.3 68.8 207.2 eV 0.0177 0.1371 1.91 4.17 3.51 4.17 0.0017 0.0001 0.09 0.31 þ1.00 þ0.69 w0.1/h (N ¼ 173, hr ¼ 36.5 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.85  0.16 (s ¼ 2.14  0.06) I: Hb ¼ 112.3  1.07 Mv; Hmax ¼ 104.8 þ 0.34 Mv; He ¼ 100.2 þ 0.71 Mv (N ¼ 116) II: Hb ¼ 103.3  0.79 Mv; Hmax ¼ 94.5 þ 0.37 Mv; He ¼ 90.4 þ 0.69 Mv (N ¼ 6) I: r w 0.58  0.38 g/cm3 (a1 ¼ 0.057 km, a2 ¼ 5.47/s) II: r w 1.1 g/cm3 (a1 ¼ 0.034 km, a2 ¼ 9.01/s) dpossibly Na poor From c and s: w56,000 y e

Meteoroid density: Age: Source:

Brief history: First identified from low-light video data by [1] from R.A. ¼ 345.1 , Decl. ¼ þ24.1 and Vg ¼ 62.5 km/s around lo ¼ 71.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409. May 25 (lo ¼ 65 )

669 CHP d chi Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.13  0.70 Annual shower May 20e29 (lo ¼ 60 e70 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 64.8 355.5 þ21.2 300.0 þ20.9 60.6 þ1.06 þ0.37 þ0.12 0.09 0.12 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 10.9 0.503 0.955 132.1 88.8 64.8 153.6 eV 0.0339 0.0588 2.35 5.74 2.87 5.74 0.0051 0.0031 0.02 0.70 þ1.00 þ0.30 w0.1/h (N ¼ 35, hr ¼ 31.5 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.91  0.25 (s ¼ 2.16  0.09) Component IIa has high end height, Ke > 82: IIa: Hb ¼ 108.7  0.27 Mv; Hmax ¼ 98.4 þ 1.60 Mv; He ¼ 95.5 þ 1.24 Mv (N ¼ 18) IIa: r w 5.2 g/cm3 (a1 ¼ 0.028 km, a2 ¼ 8.54/s) duncertain, low N From c and s: w37,000 y; Earth passes through core: sU < su e

Meteoroid density: Age: Source:

Brief history: First identified from low-light video data by [1] from R.A. ¼ 3.3 , Decl. ¼ þ21.9 and Vg ¼ 61.9 km/s around lo ¼ 71.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

258

Northern apex

June

259

June 1 (lo ¼ 71 )

456 MPS d May psi Scorpiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Years of outbursts: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.77  0.21 Episodic shower, weak annual shower April 28eJuly 8 (lo ¼ 37 e106 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 70.6 248.3 9.0 177.6 þ12.5 23.0 þ0.56 þ0.18 0.45 þ0.26 0.21 a (AU) q (AU) E i ( ) u ( ) U ( ) P ( ) 2.78 0.613 0.784 9.7 264.0 70.7 335.5 eV 0.0323 0.0723 1.22 3.74 14.34 3.74 1 þ0.0071y 0.0023 þ0.07y 0.91 þ1.00 þ0.09 ) 1 ) lo > 62 w0.5/h (N ¼ 2052, hr ¼ 43.4 , m(Mv ¼ 0) ¼ 0.28 g) 2020 c ¼ 2.60  0.08 (s ¼ 2.04  0.04) Component Ib has low He with Ke < 82: Ib: Hb ¼ 97.7  1.30 Mv; Hmax ¼ 85.7 þ 1.11 Mv; He ¼ 81.2 þ 1.54 Mv (N ¼ 1999) IIb: Hb ¼ 88.0  0.77 Mv; Hmax ¼ 81.8 þ 0.39 Mv; He ¼ 78.0 þ 0.79 Mv (N ¼ 257) Ib: r w 1.5  0.2 g/cm3 (a1 ¼ 0.084 km, a2 ¼ 3.00/s) dchondritic Na IIb: r w 2.4  0.6 g/cm3 (a1 ¼ 0.124 km, a2 ¼ 3.79/s) dpossibly Na poor/free Mg1.01 Fe0.99 Na0.060 (N ¼ 1), chondritic e 2007 WY3 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.78 0.634 0.772 11.9 51.2 285.8 337.1

Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2020-Jan-21.0 TDB

Brief history: Radiant moves out of anthelion source. Shower was detected from early CAMS and SonotaCo data in a D-criterion search by [1] from R.A. ¼ 244.5 ,  Decl. ¼ 10.6 and Vg ¼ 25.4 km/s around lo ¼ 61.5 . Confirmed by [2]. Activity curve shown in Fig. 6.2. Shower may be variable in strength, with strong showing in 2019 [3] and 2020 [4]. Source identified here, an H ¼ 18.3 object with same P, but further along rotation of nodal line. Name and number by [1]. References: [1] Rudawksa R., Jenniskens P. (2014) In: Meteoroids 2013, p. 217e224; [2] Kornos L., et al. (2014) In: Meteoroids 2013, T. J. Jopek, F. J. M. Rietmeijer, J. WataFIG 6.2 ZHR profile (ZHR scale uncertain). nabe, I. P. Williams (eds.), A.M. University Press, p. 225e233; [3] Jenniskens P., Baggaley W. J., Cooper T., et al. (2019) CBET 4642, D.W.E. Green (ed.), CBAT, p. 1e1; [4] Matlovic P., Kornos L., Kavácová M., Tóth J., Licandro J. (2020) AA 636, A122eA132.

260

Northern apex

261

June

June 1 (lo ¼ 71 )

362 JMC d June mu Cassiopeiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, toroidal, TJ ¼ þ0.94  0.35 Annual shower May 10eJune 15 (lo ¼ 50 e85 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 70.5 8.3 þ52.3 323.0 þ43.8 43.0 þ1.05 þ0.57 þ0.17 þ0.14 0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.91 0.606 0.923 69.0 98.9 68.1 166.1 eV 0.0726 0.0834 4.37 9.05 8.35 9.05 þ0.0026 þ0.0005 0.24 þ0.32 þ1.00 þ1.32 w0.6/h (N ¼ 726, hr ¼ 32.8 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.99  0.26 (s ¼ 2.19  0.10) Ib: Hb ¼ 105.4  1.05 Mv; Hmax ¼ 96.5 þ 0.61 Mv; He ¼ 91.8 þ 0.97 Mv (N ¼ 287) II: Hb ¼ 98.6  1.49 Mv; Hmax ¼ 91.9  0.14 Mv; He ¼ 87.1 þ 0.19 Mv (N ¼ 90) III: Hb ¼ 92.9  0.85 Mv; Hmax ¼ 89.6  0.43 Mv; He ¼ 86.1  0.38 Mv (N ¼ 52) Ib: r w 1.2  0.6 g/cm3 (a1 ¼ 0.075 km, a2 ¼ 4.15/s) II: r w 3.1 g/cm3 (a1 ¼ 0.073 km, a2 ¼ 5.11/s) dpossibly Na poor III: r w 2.5 g/cm3 (a1 ¼ 0.056 km, a2 ¼ 9.40/s) dpossibly Na free From c and s: w37,000 y C/1962 H1 (Honda) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.653 (1.000) 72.9 72.1 79.8 151.9

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 1962-May-12.0 TDB

Brief history: First identified in CMOR radar observations by [1] from R.A. ¼ 17.5 , Decl. ¼ þ53.9 and Vg ¼ 43.6 km/s around lo ¼ 74.0 . Confirmed from single-station video data in IMO Video Network between May 31 and June 5 with 150 meteors by [2], after a tentative identification by [3] a year earlier. Maximum on June 2. Confirmed from video triangulations by [4]. Source identified here, with C/1962 H1 having R.A. ¼ þ5.7 , Decl. ¼ þ54.1 and Vg ¼ 43.7 km/s centered on lo ¼ 68.3 for method “Hþ” of [5]. Number and name by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81; [2] Molau S., et al. (2013) JIMO 41, 133e138; [3] [5] Molau S., et al. (2012) JIMO 40, 176e180; [4] Jenniskens P., et al. (2016) Icarus 266, 355e370; [5] Neslusan L., Svoren J., Porubcan V. (1998) AA 331, 411e413. June 6 (lo ¼ 75 )

850 MBA e May beta Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age:

Long-period comet, TJ ¼ 1.04  0.61 Annual shower June 1 e 10 (lo ¼ 70 e 79 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 75.4 324.6 2.9 250.4 þ10.6 67.7 þ0.86 þ0.29 0.08 0.01 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 79.3 0.729 0.991 159.6 244.3 75.4 319.7 0.0135 0.0618 0.60 2.68 2.17 2.68 0.0006 þ0.0060 þ0.00 0.33 þ1.00 þ0.97 w0.01 /h (N ¼ 40, hr ¼ 47.9 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.86  0.22 (s ¼ 2.14  0.08) I: Hb ¼ 113.4  2.16 Mv; Hmax ¼ 104.0 þ 0.36 Mv; He ¼ 97.8 þ 1.13 Mv (N ¼ 36) I: r w 0.53 g/cm3 (a1 ¼ 0.022 km, a2 ¼ 7.45 /s) From c: w 49,000 y; From s: w25,000 y

Brief history: First reported by [1] at R.A. ¼ 323.3 , Decl. ¼ 3.1 around lo ¼ 74.3 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.



eV

with Vg ¼ 68.3 km/s

262

Northern apex

263

June

June 8 (lo ¼ 78 )

65 GDE d gamma Delphinids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source:

Long-period comet, TJ ¼ 0.57  0.30 Annual shower and episodic (1930) 2014e2015, 2020 June 5e12 (lo ¼ 75 e82 ) R.A. ( ) Decl. ( ) l ( ) lo ( ) 78.4 338.0 þ20.5 269.6 þ0.98 þ0.31 þ0.09 a (AU) q (AU) e i ( ) 14.0 1.015 0.959 133.4 0.0002 0.112 0.88 þ0.0001 0.0022 þ0.15 w0.2/h (N ¼ 93, hr ¼ 37.9 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.34  0.29 (s ¼ 1.92  0.13) Ia: Hb ¼ 116.3  1.85 Mv; Hmax ¼ 107.3 þ 0.44 Mv; Ia: low F ¼ 0.53, fragile meteoroids Ia: r  0.55 g/cm3 (a1 ¼ 0.067 km, a2 ¼ 3.92/s) Mg0.55 Fe0.91 Na0.021 (N ¼ 1) From c and s: 25,000 y e

b ( ) þ27.5 0.10 u ( ) 180.4 1.02 0.24

Vg (km/s) 65.0 þ0.01 U ( ) 78.4 1.29 þ1.00

P ( ) 258.8 1.02 þ0.76

eV

He ¼ 99.3 þ 1.58 Mv (N ¼ 56)

Brief history: Name from an outburst of 51 meteors seen by two observers with radiant at R.A. ¼ 312.6 , Decl. ¼ þ17.2 at lo ¼ 80.42 on June 11, 1930 [1,2]. Activity detected here is episodic, although some meteors seen every year: yearly number of meteors from 2007 to 2020: 1, 0, 0, 2, 3, 2, 9, 17, 14, 9, 5, 7, 5, 19. Strong change of q versus lo, high q. [2] chose to give number from [3] based on two probably unrelated photographed meteors with radiant R.A. ¼ 310.6 , Decl. ¼ þ3.9 and R.A. ¼ 322.8 , Decl. ¼ þ11.2 , respectively. Radar detections in [2] are also unrelated. Name from [1], number by [2]. References: [1] Simmons K. (1980) Meteor News 51, 2e3; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 194; [3] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129. June 2 (lo ¼ 72 )

860 PAN d psi Andromedids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.14  0.42 Annual shower May 21eJune 2 (lo ¼ 70 e74 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 72.1 355.7 þ46.7 307.5 þ43.5 50.4 þ0.77 þ0.46 þ0.13 þ0.41 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 38.9 0.707 0.981 89.6 113.0 72.1 184.6 0.0237 0.0753 1.58 4.10 0.71 4.10 þ0.0074 þ0.0051 0.54 þ0.76 þ1.00 þ1.76 w0.2/h (N ¼ 55, hr ¼ 38.4 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.22  0.21 (s ¼ 1.87  0.11) I: Hb ¼ 110.1  1.33 Mv; Hmax ¼ 101.1 þ 1.07 Mv; He ¼ 93.0 þ 1.44 Mv (N ¼ 20) I: low F ¼ 0.53, fragile meteoroids I: r  0.51 g/cm3 (a1 ¼ 0.131 km, a2 ¼ 4.11/s), lower if fragile From c: w17,000 y, from s: ~38,000 y; high dP/dlo versus i; through core (sU < su) e

eV

Brief history: Shower activity mostly during lo ¼ 70.2e73.3 . First identified in [1] from R.A. ¼ 355.9 , Decl. ¼ þ46.5 and Vg ¼ 49.9 km/s around lo ¼ 71.6 . Number and name by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

264

Northern apex

June

June 24 (lo ¼ 94 )

431 JIP d June iota Pegasids

Dynamic type: Shower type: Time of groupings:

Long period comet, TJ ¼ 0.29  0.68 Annual shower, compact with variations in activity and peak time 2009: lo ¼ 94.15e94.21 , N ¼ 6; 2011: lo ¼ 93.83e93.99 , N ¼ 15 2012: lo ¼ 94.03e94.15 , N ¼ 7; 2013: lo ¼ 94.39e94.48 , N ¼ 4 2019: lo ¼ 93.79e93.85 , N ¼ 5 2020: lo ¼ 93.88e94.92 , N ¼ 8; 2022: lo ¼ 94.00e94.10 , N ¼ 7 June 2e10 (lo ¼ 93 e96 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 94.0 331.8 þ29.2 252.5 þ37.7 58.8 þ1.04 þ0.31 þ0.20 0.11 þ0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 21.2 0.899 0.973 112.6 220.2 94.0 314.2 0.0130 0.1001 1.26 3.36 0.61 3.36 þ0.0016 þ0.0044 þ0.29 0.30 þ1.00 þ0.70 w0.4/h (N ¼ 190, hr ¼ 53.2 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.16  0.09 (s ¼ 1.84  0.05) Ib: Hb ¼ 111.2  1.53 Mv; Hmax ¼ 102.3 þ 1.35 Mv; He ¼ 97.0 þ 1.71 Mv (N ¼ 127) Ib: r w 0.67 g/cm3 (a1 ¼ 0.027 km, a2 ¼ 8.95/s) Mg0.47 Fe0.76 Na0.079 (N ¼ 1) From c and s: ~29,000 y; Earth passing through core of stream (sU < su) e

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy: Age: Source:

265

eV

Brief history: First recognized from 9 meteors in SonotaCo video data by [1] from R.A. ¼ 332.6 , Decl. ¼ þ29.2 and Vg ¼ 59.0 km/s around lo ¼ 94.5 . Confirmed in singlestation video data by [2] and from CAMS multi-station data by [3]. Name and number by [1]. References: [1] Greaves J. (2012) JIMO 40, 16e23; [2] Molau S., et al. (2012) 40, 101e105; [3] Jenniskens P., et al. (2016) Icarus 266, 355e370. June 24 (lo ¼ 108 )

411 CAN d c Andromedids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.13  0.41 Annual shower June 21eAugust 8 (lo ¼ 90 e136 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 108.2 29.9 þ47.6 298.1 þ32.8 57.2 þ1.21 þ0.36 þ0.04 þ0.02 0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.5 0.688 0.921 112.6 109.0 108.1 216.3 eV 0.0482 0.0938 3.59 7.66 8.62 7.66 0.0010 0.0010 0.25 0.01 þ1.00 þ0.99 w2/h (N ¼ 2927, hr ¼ 38.7 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.65  0.04 (s ¼ 2.40  0.02) Ib: Hb ¼ 108.8  0.86 Mv; Hmax ¼ 98.8 þ 1.17 Mv; He ¼ 93.6 þ 1.64 Mv (N ¼ 1670) III: Hb ¼ 98.0  0.61 Mv; Hmax ¼ 93.2 þ 0.11 Mv; He ¼ 88.5 þ 0.49 Mv (N ¼ 57) Ib: r w 1.2  0.3 g/cm3 (a1 ¼ 0.060 km, a2 ¼ 5.05/s) III: r w 2.4 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 9.43/s) dpossibly Na free From c and s: w83,000 y; high dP/dlo versus i e

Meteoroid density: Age: Source:

Brief history: First recognized in single-station IMO Video Meteor Network data by [1] from R.A. ¼ 32.4 , Decl. ¼ þ48.4 and Vg ¼ 58 km/s around lo ¼ 110 . Confirmed from triangulated video data by [2,3]. Name and number by [1]. References: [1] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [2] Greaves J. (2012) JIMO 40, 16e23; [2] Jenniskens P., et al. (2016) Icarus 266, 331e354.

266

Northern apex

267

June

June 26 (lo ¼ 96 )

685 JPS d June beta Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy: Age: Source:

Long-period comet, TJ ¼ 0.48  0.56 Annual shower June 12eAugust 26 (lo ¼ 94 e100 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 96.0 349.1 þ28.6 266.3 þ0.71 þ0.51 0.09 a (AU) q (AU) e i ( ) 8.49 1.009 0.945 128.7 0.0026 0.110 0.96 0.0002 þ0.0048 0.22 w0.1/h (N ¼ 67, hr ¼ 37.6 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.26  0.25 (s ¼ 1.89  0.12) I: Hb ¼ 114.0  1.96 Mv; Hmax ¼ 103.1 þ 2.37 Mv; I: r w 0.75 g/cm3 (a1 ¼ 0.021 km, a2 ¼ 6.73/s) AMOS: Mg1.00 Fe0.81 Na0.071 (N ¼ 1) [2] From c and s: w28,000 y e

b ( ) þ30.3 þ0.18 u ( ) 189.6 1.95 þ0.14

Vg (km/s) 63.6 þ0.09 U ( ) 96.0 1.38 þ1.00

P ( ) 285.9 1.95 þ1.14

eV

He ¼ 98.4 þ 2.55 Mv (N ¼ 40) duncertain due to low N

Brief history: First recognized from 13 CAMS meteors by [1] from R.A. ¼ 349.6 , Decl. ¼ þ28.4 and Vg ¼ 63.5 km/s around lo ¼ 96.0 . Number and name by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29; [2] Matlovic P., et al. (2019) AA 629, A71eA90. June 26 (lo ¼ 96 )

867 FPE d 52 Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Year of outbursts: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1822-Jul-16.3 TDB Source:

Long-period comet, TJ ¼ 0.91  0.34 Annual shower June 25e28 (lo ¼ 95 e98 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 95.9 345.1 þ11.4 254.8 þ16.3 67.3 þ0.85 þ0.27 0.09 0.09 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 64.5 0.850 0.987 150.2 227.9 95.9 323.9 eV 0.0131 0.103 0.58 3.16 0.45 3.16 0.0025 0.0014 þ0.12 þ0.51 þ1.00 þ1.50 w0.5/h (N ¼ 50, hr ¼ 39.2 , m(Mv ¼ 0) ¼ 0.02 g) 2020 (N ¼ 17, lo ¼ 95.68e95.84 : June 27, 3:35e7:31 UTC) c ¼ 2.90  0.38 (s ¼ 2.15  0.13) I: Hb ¼ 113.9  1.86 Mv; Hmax ¼ 104.6 þ 1.08 Mv; He ¼ 98.7 þ 2.40 Mv (N ¼ 37) I: r w 0.86 g/cm3 (a1 ¼ 0.044 km, a2 ¼ 10.10/s) duncertain due to low N From c and s: w46,000 y; Earth passing through core of stream (sU < su) C/1822 K1 (Pons) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.847 (1.000) 143.7 237.8 100.2 338.0 e

Brief history: First recognized from combined video data by [1] from R.A. ¼ 345.5 , Decl. ¼ þ11.6 and Vg ¼ 66.8 km/s around lo ¼ 96.7 . Not same parent body as shower #175, but parent bodies may be related. C/1822 K1 identified here has R.A. ¼ 342.7, Decl. ¼ þ13.2 and Vg ¼ 66.2 km/s around lo ¼ 97.0 according to method “P” of [2]. Number and name by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29; [2] Neslusan L., Svoren J., Porubcan V. (1998) AA 331, 411e413.

268

Northern apex

269

June

June 26 (lo ¼ 95 )

830 SCY d 63 Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1850-Jul-22.0 TDB

Long-period comet, TJ ¼ þ0.63  0.27 Annual shower June 21eJuly 1 (lo ¼ 90 e100 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 95.0 319.6 þ50.0 255.6 þ60.3 46.0 þ0.96 þ0.20 þ0.00 0.00 þ0.17 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 12.9 0.997 0.922 79.7 196.2 95.0 291.5 eV 0.0079 0.101 2.11 3.42 1.60 3.42 þ0.0002 þ0.0010 þ0.37 0.11 þ1.00 þ0.89 w0.2/h (N ¼ 199, hr ¼ 58.7 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 2.56  0.08 (s ¼ 2.02  0.03) I: Hb ¼ 108.5  1.03 Mv; Hmax ¼ 99.9 þ 0.66 Mv; He ¼ 93.1 þ 1.60 Mv (N ¼ 129) I: low F ¼ 0.56, fragile meteoroids I: r  0.49 g/cm3 (a1 ¼ 0.079 km, a2 ¼ 4.20/s), lower if fragile From c and s: w49,000 y C/1850 J1 (Petersen) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 772 1.081 0.999 68.2 180.6 95.0 275.6

Brief history: First reported by [1] from R.A. ¼ 317.1 , Decl. ¼ þ50.9 and Vg ¼ 44.4 km/s around lo ¼ 94.4 . Theoretical radiant for C/1850 J1 is R.A. ¼ 315.3 , Decl. ¼ þ60.2 and Vg ¼ 40.2 km/s around lo ¼ 95.0 according to method “P” of [2], which is 10 higher in declination. Number and name by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29; [2] Neslusan L., Svoren J., Porubcan V. (1998) AA 331, 411e413. June 28 (lo ¼ 96 )

1065 NAT d nu Arietids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1850-Jul-22.0 TDB

Long-period comet, TJ ¼ 0.40  0.67 Annual shower June 21eJuly 7 (lo ¼ 90 e105 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 95.7 37.2 þ24.1 307.3 þ0.92 þ0.31 þ0.00 a (AU) q (AU) e i ( ) 35.5 0.224 0.992 152.9 0.0369 0.0311 3.88 þ0.0003 0.0033 0.07 w0.1/h (N ¼ 28, hr ¼ 21.8 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.38  0.09 (s ¼ 2.32  0.03) Ia: Hb ¼ 111.4  0.77 Mv; Hmax ¼ 101.5 þ 1.38 Mv; Ia: r w 1.1 g/cm3 (a1 ¼ 0.163 km, a2 ¼ 3.21/s) From c and s: w21,000 y C/1533 M1 a (AU) q (AU) e i ( ) N 0.255 (1.000) 149.6

b ( ) þ9.0 0.00 u ( ) 59.0 5.90 0.07

Vg (km/s) 60.4 0.10 U ( ) 95.7 4.04 þ1.00

P ( ) 154.7 5.90 þ1.07

eV

He ¼ 95.3 þ 2.82 Mv (N ¼ 19) duncertain due to low N u ( ) 21.4

U ( ) 125.4

duncertain P ( ) 146.8

Brief history: Shower first identified here. Possible source identified here passed far from Earth orbit, using [1]. References: [1] Neslusan L., Svoren J., Porubcan V. (1998) AA 331, 411e413.

270

Northern apex

July

July 10 (lo ¼ 107 )

444 ZCS d zeta Cassiopeiids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1995-Oct-10.0 TDB

Long-period comet shower, TJ ¼ 0.09  0.48 Annual shower, possibly variable in activity 2005? June 30eJuly 24 (lo ¼ 98 e120 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 107.0 6.1 þ50.5 277.6 þ43.1 57.2 þ1.41 þ0.29 þ0.28 0.26 þ0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 22.5 0.999 0.956 107.3 164.6 112.9 277.1 0.0055 0.113 2.20 3.48 3.50 3.48 0.0013 þ0.0011 þ0.40 0.63 þ1.00 þ0.37 July 15 (lo ¼ 113.4 ) N ¼ 1740 (hr ¼ 51.0 , m(Mv ¼ 0) ¼ 0.03 g) ZHR w 1.5/h; 2005: 10e15 [1] c ¼ 3.11  0.11 (s ¼ 2.23  0.04) Ib: Hb ¼ 110.6  1.12 Mv; Hmax ¼ 101.0 þ 1.39 Mv; He ¼ 95.8 þ 1.86 Mv (N ¼ 1076) Ib: F ¼ 0.65; F ¼ 0.68  0.09 [2] Ib: r w 0.64  0.18 g/cm3 (a1 ¼ 0.0455 km, a2 ¼ 6.42/s) Mg1.00 Fe0.95 Na0.032 (N ¼ 3) From c and s: w64,000 y 109P/SwifteTuttle a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 26.1 0.960 0.963 113.5 153.0 139.4 292.4

271

eV

Brief history: Early Perseids (Fig. 6.3), but with radiant slightly offset and with distinct argument of perihelion and perihelion distance. First identified from a possible outburst of bright meteors observed during the Comets and Meteors Workshop (CMW) summer camp on July 14/15, 2005. Lightcurves showed a rapid brightness increase in the middle part [1]. Not detected during prior CMW visual observations. The Polish Fireball Network determined a radiant from four meteors at R.A. ¼ 4.7  2.5 , Decl. ¼ þ50.1  3.0 with Vg ¼ 56.3  1.5 km/s around lo ¼ 112.537  0.004 , with meteors being detected at a rate corresponding to peak ZHR ¼ 10e15 [1]. Analysis of the singlestation IMO Video Meteor Database and FIG 6.3 ZHR profiles of #444 and #7 (Perseids). double-station SonotaCo data provided a radiant at R.A. ¼ 6 , Decl. ¼ þ51 with Vg ¼ 57.4 km/s around lo ¼ 113.1 [1]. Independently discovered from an analysis of the 2008e2011 Croatian Meteor Network video data by [2] with 55 meteors from R.A. ¼ 6.9 , Decl. ¼ þ50.7 and Vg ¼ 57.3 km/s around lo ¼ 113.2 . Activity peak over early Perseid rates during lo ¼ 110e115 (Fig. 6.3). Shower possibly active in the 19th century. In 1877, for example, [3] observed 11 meteors during July 6e17 that radiated from R.A. ¼ 6 , Decl. ¼ þ53 around lo ¼ 111e116 . Possible radar detection by [4] (shower 31), with 23 meteors from R.A. ¼ 13 , Decl. ¼ þ56 during lo ¼ 112e125 . Model by [5], identifying 109P as parent. Number and name by [2]. References: [1] Zoladek P., Wisniewski, M. (2012) JIMO 40, 189e194; [2] Segon D., et al. (2012) JIMO 40, 195e200; [3] Denning W. F. (1878) MNRAS 38, 303e314; [4] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [5] Neslusan L., Hajduková M. (2022) Icarus 382, id.115015.

272

Northern apex

273

July

July 9 (lo ¼ 107 )

328 ALA d alpha Lacertids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Mass of magnitude 0 meteor: Magnitude distribution index: Age: Source:

Evolved asteroidal or JFC toroidal stream, TJ ¼ þ4.90  0.36 Annual shower July 2e18 (lo ¼ 100 e115 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 107.0 343.0 þ53.8 269.4 þ53.4 37.5 1.13 þ0.33 þ0.36 0.26 þ0.21 a (AU) q (AU) e i ( ) u ( ) U ( ) 0.945 0.844 0.105 74.7 20.5 107.4 0.0815 0.0479 5.71 37.2 4.18 0.0016 þ0.0008 þ0.20 þ1.60 þ1.00 1.098 1.009 0.101 76.7 187.0 106.9 0.0187 0.0635 5.79 35.0 4.13 þ0.0010 þ0.0003 þ0.52 1.35 þ1.00 1.089 1.002 0.080 77.7 217.1 105.3 N ¼ 186 (u w 0 ) and 77 (u w 180 ) m(Mv ¼ 0) ¼ 0.09 g e e e

FIG 6.4 Argument of perihelion (u) versus solar longitude for video-detected meteors with a < 1.5 AU and e < 0.5.

eR

P ( ) 127.4 37.2 þ2.60 297.6 35.0 0.35 322.4

e R[M] e R[M] e R[1]

Brief history: The meteoroids move in nearly circular (e w 0.1) orbits, with u clustering near 0 and 180 , more typical of the evolved toroidal source background. Meteoroid stream first reported from CMOR radar observations by [1,2], with radiant at R.A. ¼ 343 , Decl. ¼ þ49.6 and Vg ¼ 38.9 km/s around lo ¼ 105.5 . Confirmed from MAARSY data here (see map). Because a w 1 AU, we detected orbits both with u w 180 as in the original detection, and with u w 0 . Not seen in video data. Video data in general do not detect this u w 0/180 component (dashed line in Fig. 6.4). Vertical stripes in Fig. 6.4 are due to regular showers (e.g., Perseids) with badly measured velocities. Name and number by [1]. References: [1] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [2] Brown P., et al. (2010) Icarus 207, 66e81.

274

Northern apex

275

July

July 12 (lo ¼ 110 )

549 FAN d 49 Andromedids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.03  0.37 Annual shower June 9eAugust 2 (lo ¼ 78 e130 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 109.9 17.8 þ45.0 285.9 þ33.9 59.8 þ0.87 þ0.35 0.13 þ0.03 þ0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.53 0.895 0.895 118.7 138.4 109.9 248.8 eV 0.0288 0.120 3.61 6.08 11.72 6.08 þ0.0021 0.0013 þ0.01 þ0.33 þ1.00 þ1.33 w0.8/h (N ¼ 2232, hr ¼ 43.5 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.28  0.07 (s ¼ 2.29  0.03) Ib: Hb ¼ 111.0  1.16 Mv; Hmax ¼ 103.2 þ 0.55 Mv; He ¼ 96.9 þ 1.24 Mv (1237) III: Hb ¼ 98.6  0.53 Mv; Hmax ¼ 93.3 þ 0.71 Mv; He ¼ 89.3 þ 1.06 Mv (49) Ib: low F ¼ 0.55, fragile meteoroids Ib: r  0.64  0.23 g/cm3 (a1 ¼ 0.060 km, a2 ¼ 5.93/s), lower if fragile dchondr. Na III: r w 1.7 g/cm3 (a1 ¼ 0.049 km, a2 ¼ 9.80/s) dpossibly Na poor/free Na0.087 (N ¼ 1) w20,000 [4]; from c and s: w96,000 y; high dP/dlo versus i 507 UANdupsilon Andromedids C/2001 W2 (BATTERS) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.9 1.051 0.941 115.9 142.1 113.4 255.5

Lightcurve shape: Meteoroid density: Spectroscopy: Age: Alternative name: Source: Orbital elements (J2000.0) Epoch 2001-Dec-05.0 TDB

Brief history: Shower first identified from CAMS data by [1] from 13 meteors radiating from R.A. ¼ 19.8 , Decl. ¼ þ42.5 and Vg ¼ 58.8 km/s around lo ¼ 98.0 (range 93.3e101.9 ). Listed as shower #507 UANdupsilon Andromedids. Confirmed from Croatian Meteor Network and SonotaCo database by [2], and given name #549 FANd49 Andromedids. Also detected by [3]. #549 was first of these detections to be moved to the list of established showers. [2] proposed parent body C/2001 W2, model by [4], showing stream is older than a few centuries. Linked to 109P by [5], instead. Name and number by [2]. References: [1] Holman D., Jenniskens P. (2013) JIMO 41, 43e47; [2] Andreic Z. (2014) JIMO 42, 90e97; [3] Jenniskens P., et al. (2016) Icarus 266, 384e409; [4] Segon D., et al. (2017) AA 598, A15eA28; [5] Neslusan L., Hajduková M. (2022) Icarus 382, id.115015. July 11 (lo ¼ 109 )

829 JSP d July 77 Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age:

Long-period comet, TJ ¼ 0.72  0.44 Annual shower July 6e17 (lo ¼ 104 e115 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 108.8 353.9 þ9.1 249.3 þ10.7 66.5 þ0.81 þ0.26 0.14 0.08 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 21.1 0.687 0.967 158.7 249.6 108.8 359.1 0.0245 0.0688 1.01 4.01 2.48 4.01 0.0039 þ0.0005 þ0.13 þ0.47 þ1.00 þ1.47 w0.1/h (N ¼ 119, hr ¼ 47.7 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.93  0.40 (s ¼ 2.17  0.15) Ib: Hb ¼ 111.6  1.27 Mv; Hmax ¼ 103.2 þ 0.86 Mv; He ¼ 96.7 þ 1.99 Mv (N ¼ 67) Ib: low F ¼ 0.56, fragile meteoroids Ib: r  0.48 g/cm3 (a1 ¼ 0.106 km, a2 ¼ 4.35/s), lower if fragile From c and s: w42,000 y

[see plate on p. 280]

eV

276

Northern apex

277

July

Brief history: Shower first detected by [1] from R.A. ¼ 355.1 , Decl. ¼ þ9.4 and Vg ¼ 66.3 km/s around lo ¼ 110.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29. July 18 (lo ¼ 115 )

187 PCA d psi Cassiopeiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, toroidal, TJ ¼ 2.25  0.55 Annual shower July 13e21 (lo ¼ 110 e118 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 115.3 26.0 þ70.0 304.5 þ53.7 42.2 þ1.02 þ0.37 0.12 þ0.06 0.17 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.80 0.846 0.696 76.2 126.4 115.3 241.6 eV 0.0474 0.129 2.75 8.33 1.99 8.33 þ0.0004 0.0096 0.17 0.23 þ1.00 þ0.77 w0.7/h (N ¼ 176, hr ¼ 44.6 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 3.09  0.52 (s ¼ 2.22  0.17) IIa: Hb ¼ 103.5  1.97 Mv; Hmax ¼ 97.3  1.44 Mv; He ¼ 92.1  1.27 Mv (27) III: Hb ¼ 92.8  0.04 Mv; Hmax ¼ 89.1 þ 0.48 Mv; He ¼ 84.1 þ 0.70 Mv (112) IIa: Low F ¼ 0.54, fragile IIa: r  1.3 g/cm3 (a1 ¼ 0.052 km, a2 ¼ 6.50/s), lower if fragile III: r w 3.1 g/cm3 (a1 ¼ 0.026 km, a2 ¼ 9.63/s) dpossibly Na poor/free

Lightcurve shape: Meteoroid density: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

July 13e19 (lo ¼ 110 e116 ) lo (  ) R.A. ( ) Decl. ( ) 114.4 19.0 þ67.2 þ0.98 þ0.59 a (AU) q (AU) e 1.93 0.855 0.558 0.0489 0.170 0.0040 0.0289 2.481 0.821 0.669 N ¼ 28

Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

e 5496 (1973 NA) a (AU) q (AU) 2.44 0.888

e 0.635

l ( ) 297.1 þ0.14 i ( ) 77.1 4.50 0.94 72.1

b ( ) þ52.8 þ0.21 u ( ) 123.4 7.52 1.91 121.2

Vg (km/s) 42.7 0.74 U ( ) 114.4 1.42 þ1.00 114.4

i ( ) 68.0

u ( ) 118.0

U ( ) 101.0

P ( ) 237.1 7.52 0.91 235.6

e R[H] e R[1]

duncertain P ( ) 219.0

Brief history: Shower first detected from Kharkiv radar data by [1] from 23 meteors radiating from R.A. ¼ 21.0 , Decl. ¼ þ75.3 and Vg ¼ 40.3 km/s around lo ¼ 114.4 (shower 25). Confirmed by [2]. Strong shower in CMOR data. Here, we find a weak video-detected shower separated from the background mainly in Vg. [3] proposed 1973 NA as the parent body. Name by [2], number by [3]. Possibly related to shower #1133. References: [1] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [2] Sekanina Z. (1976) Icarus 27, 265e321; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 718.

278

Northern apex

July

279

July 7 (lo ¼ 105 )

1133 TCS d 32 Cassiopeiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ0.83  0.47 Annual shower July 3e11 (lo ¼ 101 e109 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 105.1 14.5 þ65.8 304.0 þ52.8 46.3 þ1.16 þ0.45 þ0.08 þ0.04 0.22 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.24 0.857 0.897 80.4 131.9 105.1 236.8 eV 0.0229 0.121 2.49 4.92 1.82 4.92 þ0.0003 0.0077 0.24 0.08 þ1.00 þ0.92 w0.4/h (N ¼ 180, hr ¼ 44.9 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 2.69  0.33 (s ¼ 2.07  0.15) III: Hb ¼ 93.8  0.30 Mv; Hmax ¼ 89.2 þ 0.46 Mv; He ¼ 85.6 þ 0.46 Mv (N ¼ 106) III: r w 2.0  0.5 g/cm3 (a1 ¼ 0.098 km, a2 ¼ 8.31/s) dpossibly Na free or iron From c and s: w30,000 y e

Brief history: First reported here. Only component III (low beginning height) lightcurves. More compact shower and earlier in lo than the diffuse radar shower #187. Possibly related. July 15 (lo ¼ 113 )

1068 TPE d July theta Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 770-Jun-05.8 TDB Source:

Long-period comet, TJ ¼ 0.04  0.29 Annual shower July 7e29 (lo ¼ 105 e127 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 112.6 46.8 þ48.2 305.9 þ29.6 56.1 þ1.80 0.01 þ0.32 0.35 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 19.1 0.543 0.972 110.3 92.7 112.6 204.6 eV 0.0456 0.0701 2.62 6.75 6.03 6.75 0.0097 þ0.0026 þ0.21 1.10 þ1.00 0.10 July 11 (lo ¼ 109 ) w0.08/h (N ¼ 127, hr ¼ 35.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.63  0.09 (s ¼ 2.05  0.04) Ib: Hb ¼ 110.0  1.45 Mv; Hmax ¼ 100.9 þ 1.05 Mv; He ¼ 96.5 þ 1.15 Mv (N ¼ 55) Ib: r w 0.87 g/cm3 (a1 ¼ 0.120 km, a2 ¼ 5.97/s) From c: w28,000 y, from s: w55,000 y C/770 K1 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.580 (1.000) 117.0 88.0 110.7 198.7 e

Brief history: Shower first identified here. Spread along toroidal ring (þ23 to þ32 ), decreasing latitude with increasing solar longitude, densest part at onset around lo ¼ 109 .

280

Northern apex

July

281

July 15 (lo ¼ 113 )

175 JPE d July Pegasids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Model: (40,000 y, br ¼ 0.001) Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.44  0.44 Annual shower 2008, 2011 [2] July 1eAugust 19 (lo ¼ 98 e146 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 113.1 351.7 þ12.0 244.1 þ14.2 63.9 þ0.85 þ0.29 0.10y 0.07y 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 14.9 0.559 0.968 149.2 265.4 113.1 18.4 eV 0.0360 0.0716 1.41 5.81 9.82 5.81 0.0038 0.0003 þ0.07 þ0.44 þ1.00 þ1.44 37 0.551 0.985 148.7 263.5 113.0 16.5 e [10] N ¼ 1821 (hr ¼ 46.9 , m(Mv ¼ 0) ¼ 0.02 g) 3.1  0.1 [8]; 5 [11] c ¼ 2.97  0.07 (s ¼ 2.18  0.02); 3.0 [11] Component IIb has low He, Ke < 79, like III: Ib: Hb ¼ 111.7  1.26 Mv; Hmax ¼ 101.2 þ 1.30 Mv; He ¼ 96.1 þ 1.72 Mv (1000) III: Hb ¼ 99.6  0.43 Mv; Hmax ¼ 95.0  0.00 Mv; He ¼ 90.4  0.07 Mv (19) Ib: r w 0.62  0.28 g/cm3 (a1 ¼ 0.044 km, a2 ¼ 7.68/s) III: r w 7.7 g/cm3 (a1 ¼ 0.089 km, a2 ¼ 7.03/s) e possibly Na free Mg0.94 Fe1.06 Na0.083 (N ¼ 2) EN150723_215141: PE ¼ 5.73, Max. dyn. press. ¼ 0.031 MPa at Hm ¼ 84.14 km [12] 40,000 y and br ¼ 0.001 best model fit to this data [10] C/1979 Y1 (Bradfield) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 45.6 0.545 0.988 148.6 257.6 103.2 0.8 C/1771 A1 (Great Comet) N 0.528 (1.000) 148.6 260.4 111.9 12.3

Meteoroid density: Spectroscopy: Strength: Age: Source: Orbital elements (J2000.0) Epoch 1980-Jan-25.0 TDB Source: Epoch 1770-Nov-22.7 TDB

Brief history: [1] Calculated a theoretical radiant for C/1979 Y1 meteoroids near R.A. ¼ 346 , Decl. ¼ þ10 on July 10. Shower listed by [2] and [3] as linked to C/1979 Y1. Initial video observations by [4] suggested the shower did not exist. Identified in singlestation video data by [5] and from double station data by [6] and [7]. Also detected by CMOR [9]. Video-derived activity curve shown in Fig. 6.5. Association with both C/1979 Y1 and C/1771 A1 by [7]. Model by [10], “Filament F1”. Number and name by [3]. References: [1] Olsson-Steel D. (1987) Austr. J. of Astron. 2, 21e35; [2] Rendtel J., Arlt R., McBeath A. (1995) Handbook for Visual Meteor Observers. Potsdam: IMO, pp 169e170; [3] Jenniskens P. FIG 6.5 ZHR profile. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [4] Triglav-Cekada M., Arlt R. (2005) JIMO 33, 129e134; [5] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [6] Ueda M. (2012) JIMO 40, 59e64; [7] Holman D., Jenniskens P. (2013) JIMO 41, 43e47; [8] Olech A., Wisniewski M. (2002) AA 384, 711e724; [9] Brown P., et al. (2010) Icarus 207, 66e81; [10] Hajduková M., Neslusan L. (2017) AA 605, A36eA48; [11] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [12] Spurny P., et al. (2017) AA 605, A68e93.

282

Northern apex

July

283

July 20 (lo ¼ 117 )

372 PPS d phi Piscids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.34  0.36 Annual shower June 12eAugust 26 (lo ¼ 81 e152 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 117.1 28.1 þ30.5 280.6 þ17.5 66.5 þ0.85 þ0.37y 0.15 þ0.08 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.49 0.929 0.892 148.6 144.9 117.1 262.2 eV 0.0262 0.114 6.62 6.34 17.7 6.34 þ0.0024 0.0008 0.12y þ0.55 þ1.00 þ1.55 2.09 0.856 0.590 152.6 125.0 106.0 231.0 e R[1] w3.6/h (N ¼ 10,512, hr ¼ 39.3 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.44  0.05 (s ¼ 2.34  0.02) Ib: Hb ¼ 112.7  0.97 Mv; Hmax ¼ 104.4 þ 0.90 Mv; He ¼ 98.5 þ 1.58 Mv (6309) III: Hb ¼ 100.3  0.55 Mv; Hmax ¼ 94.9 þ 0.76 Mv; He ¼ 90.4 þ 0.85 Mv (268) Ib: low F ¼ 0.58, fragile meteoroids If similar to #31: r ¼ 0.5  0.2 g/cm3 [4] Ib: r  0.64  0.09 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 6.48/s), lower if fragile dNa poor III: r w 1.7  0.6 g/cm3 (a1 ¼ 0.037 km, a2 ¼ 14.15/s) Mg0.93 Fe0.66 Na0.017 (N ¼ 6) From c and s: w110,000 y 190 BPEdbeta Perseids 1P/Halley a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.8 0.586 0.967 162.3 111.3 58.4 169.7

Lightcurve shape: Meteoroid density:

Spectroscopy: Age: Alternative name: Source: Orbital elements (J2000.0) Epoch 1994-Feb-17.0 TDB

Brief history: Shower evolves smoothly from #31, hence source is 1P/Halley. Long known as a visual shower “beta-Perseids” (IAU#190) has radiant nearby at l ¼ 285 , b ¼ þ20 ,   Vg ¼ 66 km/s on lo ¼ 235 (132e143 ) [5]. Reported from 2002 to 2008 CMOR radar data from the northern apex source by [1] with R.A. ¼ 20.1 , Decl ¼ þ24.1 , Vg ¼ 62.9 km/s, moving at þ1.56 in R.A. and þ0.36 in Decl. during July 6e9 only. Confirmed from CAMS video observations by [2]. Activity curve shown in Fig. 6.6. [3] split off a component shower #547 at lower latitudes. After lo ¼ 150 , when q grows to larger than Sun-Earth distance, shower continues to be detected until at least lo ¼ 210 as a diffuse source in the northern apex source. After lo ¼ 180 , this source grows to contain meFIG 6.6 ZHR profile (•), vertical scale uncertain. teors with low q. Number and name by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81; [2] Holman D., Jenniskens P. (2013) JIMO 41, 43e47; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Narziev M. (2019) PSS 173, 42e48; [5] Molau S., Rendtel J. (2009) JIMO 37, 98e121.

284

Northern apex

285

July

July 27 (lo ¼ 125 )

869 UCA d upsilon1 Cassiopeiids

Dynamic type: Shower type: Year of meteor outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age:

Long-period comet, TJ ¼ þ0.18  0.50 Annual shower e July 24e28 (lo ¼ 122 e126 ) R.A. ( ) Decl. ( ) l ( ) lo ( ) 124.9 10.5 þ59.5 275.7 þ1.35 þ0.41 þ0.21 a (AU) q (AU) e i ( ) 7.85 1.009 0.935 98.4 0.0027 0.0957 1.57 0.0006 þ0.0090 þ0.21 w0.3/h (N ¼ 95, 51.2 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.78  0.13 (s ¼ 2.11  0.05) Ib: Hb ¼ 109.1  1.41 Mv; Hmax ¼ 100.5 þ 1.50 Mv; Ib: r w 0.81 g/cm3 (a1 ¼ 0.052 km, a2 ¼ 5.19/s) From c and s: w46,000 y; high dP/dlo versus i Earth passing through core of stream (sU < su) e

Source:

b ( ) þ48.9 0.08 u ( ) 170.5 1.80 0.26

Vg (km/s) 53.9 þ0.00 U ( ) 124.9 0.71 þ1.00

P ( ) 295.3 1.80 þ0.74

eV

He ¼ 95.6 þ 1.61 Mv (N ¼ 48)

Brief history: Shower first detected by [1] from R.A. ¼ 9.3 , Decl. ¼ þ59.6 and Vg ¼ 53.5 km/s around lo ¼ 124.9 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29. July 25 (lo ¼ 123 )

177 BCA d beta Cassiopeiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.34  0.35 Annual shower July 23e28 (lo ¼ 121 e126 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 122.9 346.2 þ56.9 258.5 þ1.02 þ0.71 þ0.56 a (AU) q (AU) e i ( ) 21.9 0.995 0.955 88.4 0.0047 0.0902 1.07 þ0.0022 þ0.0023 þ0.17 w0.03/h (N ¼ 44, 66.4 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 1.70  0.10 (s ¼ 1.58  0.07) Ib: Hb ¼ 108.4  0.36 Mv; Hmax ¼ 99.8 þ 1.05 Mv; Ib: low F ¼ 0.55, fragile meteoroids Ib: r  0.38 g/cm3 (a1 ¼ 0.044 km, a2 ¼ 6.71/s) From c and s: 9600 y; high dP/dlo versus i e

b ( ) þ55.0 þ0.15 u ( ) 196.1 2.05 1.03

Vg (km/s) 49.9 þ0.28 U ( ) 122.9 0.89 þ1.00

P ( ) 319.5 2.05 0.03

eV

He ¼ 92.8 þ 1.39 Mv (N ¼ 23) duncertain due to low N

Brief history: Brief shower, first detected from a D-criterion search of photographed orbits by [1] from R.A. ¼ 352.9 , Decl. ¼ þ58.8 and Vg ¼ 50.4 km/s around lo ¼ 126.6 , centered on a peak time just outside the activity period found here. Independently found by [2], who entered the shower as #871 in the Working List with coordinates R.A. ¼ 345.9 , Decl. ¼ þ56.7 and Vg ¼ 49.9 km/s around lo ¼ 122.9 . Name by [1] and number by [3]. References: [1] Porubcan V., Gavajdova M. (1994) PSS 42, 151e155; [2] Jenniskens P., et al. (2018) PPS 154, 21e29; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp.

286

Northern apex

July

287

July 30 (lo ¼ 128 )

1074 JAC d July alpha Camelopardalids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.07  0.40 Annual shower July 24eAugust 3 (lo ¼ 122 e132 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 127.9 84.5 þ72.7 319.7 þ49.4 43.2 þ2.73 þ0.03 þ0.27 0.05 0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.85 0.719 0.905 71.0 111.7 127.9 240.4 eV 0.0043 0.0693 1.36 1.21 2.31 1.21 0.0020 0.0019 0.26 0.26 þ1.00 þ0.74 e (N ¼ 54, hr ¼ 32.9 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.82  0.15 (s ¼ 2.12  0.06) Ib: Hb ¼ 106.0  1.42 Mv; Hmax ¼ 97.9 þ 0.01 Mv; He ¼ 90.2 þ 1.86 Mv (12) IIb: Hb ¼ 97.3  1.27 Mv; Hmax ¼ 93.6  0.42 Mv; He ¼ 87.6 þ 0.44 Mv (14) Ib: low F ¼ 0.51, fragile meteoroids Ib: r  0.88 g/cm3 (a1 ¼ 0.074 km, a2 ¼ 3.99/s) duncertain due to low N IIb: r w 4.0 g/cm3 (a1 ¼ 0.027 km, a2 ¼ 7.59/s) dpossibly Na poor/free From c and s: w21,000 y e

Lightcurve shape: Meteoroid density: Age: Source:

Brief history: First reported here. July 31 (lo ¼ 129 )

870 JPG d July eta Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age:

Long-period comet, TJ ¼ þ0.28  0.47 Annual shower July 28eAugust 4 (lo ¼ 126 e133 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 128.6 340.3 þ33.2 228.8 þ38.0 51.0 þ0.96 þ0.43 0.15 0.01 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.2 0.581 0.967 91.6 262.5 128.6 30.9 0.0316 0.0494 1.57 4.39 1.41 4.39 þ0.0008 0.0018 þ0.13 0.05 þ1.00 þ0.95 w0.1/h (N ¼ 91, 61.0 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 3.24  0.05 (s ¼ 2.28  0.02) Ib: Hb ¼ 107.2  0.65 Mv; Hmax ¼ 99.0 þ 0.82 Mv; He ¼ 95.0 þ 1.12 Mv (N ¼ 41) Ib: r w 1.3 g/cm3 (a1 ¼ 0.042 km, a2 ¼ 9.39/s), uncertain due to low N From c and s: w43,000 y; high dP/dlo versus i Earth seems to be passing through core of stream (sU < su) C/1871 V1 (Tempel) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 161.3 0.691 0.996 98.3 242.9 148.9 31.8 e

Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source:

eV

Brief history: Shower first detected by [1] from R.A. ¼ 339.9 , Decl. ¼ 33.5 and Vg ¼ 51.5 km/s around lo ¼ 128.1 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29.

288

Northern apex

289

August

August 1 (lo ¼ 130 )

1075 AGP d August gamma Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.26  0.39 Annual shower July 27eAugust 4 (lo ¼ 125 e133 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 130.2 2.8 12.8 237.5 þ0.85 þ0.45 0.04 a (AU) q (AU) e i ( ) 13.5 0.354 0.974 152.1 0.0214 0.0243 1.40 0.0012 0.0009 0.24 w0.04/h (N ¼ 46, hr ¼ 45.6 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.52  0.32 (s ¼ 2.00  0.14) Ib: Hb ¼ 110.4  1.15 Mv; Hmax ¼ 100.5 þ 1.50 Mv; Ib: r w 0.58 g/cm3 (a1 ¼ 0.060 km, a2 ¼ 5.47/s) From c and s: w16,000 y e

b ( ) þ10.8 þ0.08 u ( ) 288.6 3.34 þ0.17

Vg (km/s) 61.5 0.06 U ( ) 130.2 2.27 þ1.00

P ( ) 58.6 3.34 þ1.17

eV

He ¼ 95.4 þ 1.40 Mv (N ¼ 27) duncertain due to low N

Brief history: First reported here. July 31 (lo ¼ 128 )

1135 JOM d July omega Piscids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.43  0.45 Annual shower July 23eAugust 2 (lo ¼ 120 e133 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 128.0 1.1 þ8.7 237.1 þ7.8 62.1 þ0.84 þ0.32 0.07 þ0.16 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 21.6 0.332 0.985 158.9 290.8 128.0 58.3 eV 0.0236 0.0267 2.20 3.59 4.13 3.59 0.0034 þ0.0007 0.11 þ0.38 þ1.00 þ1.38 w0.04/h (N ¼ 72, hr ¼ 50.7 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.59  0.07 (s ¼ 2.03  0.04) Ib: Hb ¼ 110.4  0.63 Mv; Hmax ¼ 99.8 þ 1.52 Mv; He ¼ 94.7 þ 2.03 Mv (N ¼ 44) Ib: r w 1.02 g/cm3 (a1 ¼ 0.029 km, a2 ¼ 8.85/s) duncertain due to low N From c: w18,000 y e

Brief history: First reported here. [1] reported a nearby shower centered on lo ¼ 135.65 , just outside the window detected here, with R.A. ¼ 7.1 , Decl. ¼ þ12.4 and Vg ¼ 59.72 km/s. References: [1] Amaral L. S., et al. (2020) JIMO 48, 69e88.

290

Northern apex

August

August 3 (lo ¼ 131 )

435 MPR d mu Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.21  0.35 Annual shower July 19eAugust 15 (lo ¼ 117 e145 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 130.6 54.4 þ48.7 293.7 þ28.4 60.9 þ1.32 þ0.23 þ0.02 0.01 0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.2 0.732 0.949 124.2 115.0 130.5 245.6 0.0208 0.0461 2.45 3.20 6.68 3.20 0.0008 0.0015 0.02 þ0.12 þ1.00 þ0.88 w0.2/h (N ¼ 252, hr ¼ 44.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.66  0.17 (s ¼ 2.41  0.05) Ib: Hb ¼ 109.9  0.76 Mv; Hmax ¼ 101.5 þ 0.58 Mv; He ¼ 96.0 þ 0.99 Mv (N ¼ 138) Ib: r w 0.84  0.50 g/cm3 (a1 ¼ 0.029 km, a2 ¼ 8.92/s) From c: w71,000 y e

291

eV

Brief history: [1] identified a shower from double-station intensified video observations performed during 1992e2009. From five meteoroid orbits, a radiant was determined at R.A. ¼ 70.4  4.6 , Decl. ¼ þ50.0  2.6 with Vg ¼ 54.2  3.8 km/s centered on lo ¼ 139.64  0.54 (or R.A. ¼ 58.5  4.6 , Decl. ¼ þ47.9  2.6 at lo ¼ 130.6 ). The velocity is lower than found here by 6.5  3.9 km/s, so within 2s. Name and number by [1]. References: [1] Shigeno Y., Yamamoto M. (2012) JIMO 40, 24e35. August 6 (lo ¼ 133 )

736 XIP d xi Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.66  0.25 Annual shower July 31eAugust 10 (lo ¼ 128 e138 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 133.3 63.4 þ35.0 294.6 þ13.6 65.2 þ1.02 þ0.25 0.10 þ0.09 þ0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 29.0 0.601 0.979 151.5 100.4 133.3 233.8 0.0283 0.0472 1.25 4.07 2.62 4.07 þ0.0053 þ0.0060 0.08 þ0.78 þ1.00 þ1.78 w0.2/h (N ¼ 103, hr ¼ 32.5 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.75  0.12 (s ¼ 2.10  0.05) Ib: Hb ¼ 111.5  0.84 Mv; Hmax ¼ 103.0 þ 1.36 Mv; He ¼ 98.6 þ 1.84 Mv (N ¼ 49) F ¼ 0.66 Ib: r w 1.3  0.3 g/cm3 (a1 ¼ 0.039 km, a2 ¼ 6.04/s) From c and s: w34,000 y e

eV

Brief history: Shower first detected by [1] from R.A. ¼ 60.0 , Decl. ¼ þ33.4 and Vg ¼ 66.3 km/s around lo ¼ 129.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

292

Northern apex

August

August 8 (lo ¼ 135 )

465 AXC d August xi Cassiopeiids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age:

Long-period comet, TJ ¼ þ0.08  0.42 Annual shower 2016? (N ¼ 11, lo ¼ 135.59e135.70 ) August 4e12 (lo ¼ 131 e139 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 135.4 3.8 þ48.9 252.1 þ42.4 55.8 þ1.36 þ0.30 þ0.24 0.23 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.8 0.909 0.919 104.5 218.4 135.4 353.7 0.0167 0.108 1.76 4.01 1.41 4.01 þ0.0003 0.0054 þ0.35 þ0.02 þ1.00 þ1.02 w0.3/h (N ¼ 327, hr ¼ 68.7 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.62  0.11 (s ¼ 2.04  0.04) Ib: Hb ¼ 110.3  1.07 Mv; Hmax ¼ 103.2 þ 0.45 Mv; He ¼ 97.0 þ 1.25 Mv (N ¼ 143) Ib: low F ¼ 0.53, fragile meteoroids Ib: r  0.41 g/cm3 (a1 ¼ 0.047 km, a2 ¼ 8.57/s), lower if fragile From c and s: w48,000 y; high dP/dlo versus i Earth seems to be passing through core of stream (sU < su) e

Source:

293

eV

Brief history: First detected in a D-criterion search of early CAMS and SonotaCo video observations by [1] from R.A. ¼ 4.9 , Decl. ¼ þ48.9 and Vg ¼ 55.5 km/s around lo ¼ 135.8 . Confirmed by [2,3]. Name and number by [1]. References: [1] Rudawska R., Jenniskens P. (2014) In: Meteoroids 2013. Eds.: T. J. Jopek, F. J. M. Rietmeijer, J. Watanabe, I. P. Williams, Poznan: A.M. University Press, p. 217e224; [2] Kornos L., et al. (2014) In: Meteoroids 2013. Eds: T. J. Jopek, F. J. M. Rietmeijer, J. Watanabe, I. P. Williams, Poznan: A.M. University Press, p. 225e233; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354. August 11 (lo ¼ 138.2 )

922 PPE d August phi Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.08  0.54 Annual shower August 3e18 (lo ¼ 130 e146 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 138.2 358.2 þ20.6 229.2 þ19.4 56.2 þ0.85 þ0.64 þ0.04 þ0.24 0.16 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 19.3 0.276 0.986 119.7 297.3 138.2 76.3 0.0317 0.0345 3.00 5.42 3.48 5.42 þ0.0022 0.0030 0.58 0.13 þ1.00 þ0.87 w0.03/h (N ¼ 86, hr ¼ 55.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.79  0.24 (s ¼ 2.11  0.09) IIa: Hb ¼ 107.2  2.48 Mv; Hmax ¼ 96.7  0.79 Mv; He ¼ 91.8  0.22 Mv (N ¼ 35) IIa: r w 0.96 g/cm3 (a1 ¼ 0.102 km, a2 ¼ 7.46/s), uncertain due to low N From c and s: w19,600 y e

eV

Brief history: First reported by [1] from R.A. ¼ 356.6 , Decl. ¼ þ20.6 and Vg ¼ 56.2 km/s around lo ¼ 137.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29.

294

Northern apex

August

August 13 (lo ¼ 140 )

696 OAU d omicron Aurigids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density:

Long-period comet, TJ ¼ 0.23  0.40 Annual shower August 8e19 (lo ¼ 135 e146 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 139.7 72.5 þ47.5 297.4 þ24.7 61.2 þ1.29 þ0.26 0.01 þ0.15 0.16 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.6 0.627 0.959 127.9 102.5 139.7 241.7 0.0239 0.0673 1.17 4.16 2.64 4.16 0.0004 0.0068 0.35 0.20 þ1.00 þ0.80 w0.08/h (N ¼ 55, hr ¼ 25.5 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.38  0.07 (s ¼ 1.94  0.03) I: Hb ¼ 112.1  1.35 Mv; Hmax ¼ 104.3  0.19 Mv; He ¼ 98.2 þ 0.03 Mv (N ¼ 23) I: low F ¼ 0.56, fragile meteoroids r ¼ 0.68  0.40 g/cm3 [3] I: r  0.88 g/cm3 (a1 ¼ 0.078 km, a2 ¼ 3.54/s), uncertain due to low N From c and s: w28,000 y 109P/SwifteTuttle a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 26.1 0.960 0.963 113.5 153.0 139.4 292.4

Age: Source: Orbital elements (J2000.0) Epoch 1995-Oct-10.0 TDB

295

eV

Brief history: First reported by [1] from R.A. ¼ 84.5 , Decl. ¼ þ48.0 and Vg ¼ 62.1 km/s around lo ¼ 148.0 . Name and number by [1]. Possible link to 109P/SwifteTuttle by [2]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409; [2] Neslusan L., Hajduková M. (2022) Icarus 382, id.115015; [3] J.-B. Kikwaya Eluo (2011) Bulk density of small meteoroids. PhD Thesis, London: University of Western Ontario, p. 234. August 11 (lo ¼ 138 )

872 ETR d epsilon Triangulids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.62  0.49 Annual shower August 8e13 (lo ¼ 135 e140 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 137.5 27.7 þ33.9 260.4 þ21.1 66.6 þ0.98 þ0.40 0.04 þ0.06 0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.7 0.945 0.940 143.0 210.6 137.5 348.0 0.0049 0.0854 0.67 1.58 1.15 1.58 0.0008 0.0040 0.13 þ0.19 þ1.00 þ1.19 w0.06/h (N ¼ 52, hr ¼ 49.7 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.14  0.15 (s ¼ 1.83  0.07) I: Hb ¼ 113.7  1.28 Mv; Hmax ¼ 105.0 þ 1.36 Mv; He ¼ 99.4 þ 2.21 Mv (N ¼ 27) I: r w 0.92 g/cm3 (a1 ¼ 0.018 km, a2 ¼ 11.15/s), uncertain due to low N From c and s: w19,000 y e

eV

Brief history: First reported by [1] with R.A. ¼ 27.6 , Decl. ¼ þ33.6 and Vg ¼ 66.7 km/s around lo ¼ 137.6 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29.

296

Northern apex

297

August

August 15 (lo ¼ 142 )

546 FTC d 43 Cassiopeiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.36  0.45 Annual shower August 7e26 (lo ¼ 135 e154 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 142.4 25.6 þ68.2 275.0 þ51.7 51.8 þ2.12 þ0.31 þ0.31 0.17 þ0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.5 1.009 0.906 93.5 172.7 142.4 316.2 eV 0.0065 0.112 2.67 6.14 4.51 6.14 0.0007 þ0.0039 þ0.27 0.53 þ1.00 þ0.47 w0.6/h (N ¼ 853 hr ¼ 51.2 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.86  0.33 (s ¼ 2.14  0.13) Ib: Hb ¼ 108.6  0.90 Mv; Hmax ¼ 99.4 þ 1.09 Mv; He ¼ 94.7 þ 1.32 Mv (N ¼ 338) III: Hb ¼ 96.8  0.89 Mv; Hmax ¼ 91.2 þ 0.09 Mv; He ¼ 87.4 þ 0.31 Mv (N ¼ 29) Ib: r w 0.70  0.56 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 6.33/s) III: r < 6.4 g/cm3 (a1 ¼ 0.182 km, a2 ¼ 3.81/s) dpossibly Na poor/free From c and s: w80,000 y; high dP/dlo versus i C/1939 V1 (Friend) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 336.6 0.945 0.997 93.0 126.8 197.1 323.9

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1995-Oct-10.0 TDB

Brief history: Center of stream just outside Earth’s orbit. First reported by [1] based on 14 meteors from R.A. ¼ 30.2 , Decl. ¼ þ67.4 and Vg ¼ 52.2 km/s around lo ¼ 144.1 . Discussed from EDMOND data by [2]. Name and number by [1]. Radiant is close to that of #7, the Perseids. Perihelion distance close to the limit, suggesting that the core of the stream is just outside of Earth orbit. Name and number by [1]. References: [1] Kornos L., et al. (2014) In: Meteoroids 2013. Eds: T. J. Jopek, F. J. M. Rietmeijer, J. Watanabe, I. P. Williams, Poznan: A.M. University Press, p. 225e233; [2] Gorelli R. (2016) JIMO 44, 108e115. August 13 (lo ¼ 141 ) 1136 AGA d August gamma Camelopardalids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

[see map on p. 78]

Long-period comet, TJ ¼ þ0.48  0.53 Annual shower August 9e17 (lo ¼ 137 e145 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 140.9 45.7 þ71.3 287.8 þ51.3 50.8 þ1.49 þ0.16 0.21 0.08 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 10.1 0.955 0.907 91.1 151.6 140.9 291.9 e V 0.0171 0.0971 1.85 4.35 2.13 4.35 þ0.0004 0.0098 þ0.06 þ0.10 þ1.00 þ1.10 w0.6/h (N ¼ 119, hr ¼ 45.8 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.82  0.37 (s ¼ 2.12  0.15) Ib: Hb ¼ 109.2  0.81 Mv; Hmax ¼ 101.3 þ 0.34 Mv; He ¼ 94.9 þ 1.32 Mv (N ¼ 56) II: Hb ¼ 102.1  3.76 Mv; Hmax ¼ 91.6 þ 0.02 Mv; He ¼ 87.9 þ 0.32 Mv (N ¼ 5) Ib: low F ¼ 0.55, fragile meteoroids Ib: r  0.33  0.13 g/cm3 (a1 ¼ 0.048 km, a2 ¼ 5.76/s), lower if fragile II: r w 0.53 g/cm3 (a1 ¼ 0.997 km, a2 ¼ 2.99/s) dpossibly Na poor/free From c and s: w59,000 y; high dP/dlo versus i 109P/SwifteTuttle

Brief history: This weak shower just north of the Perseids is first reported here.

298

Northern apex

August

August 13 (lo ¼ 141 )

831 GPG d gamma Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.02  0.45 Annual shower July 30eAugust 28 (lo ¼ 127 e155 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 140.8 5.0 þ14.1 229.8 þ11.2 57.9 þ0.74 þ0.33 0.20 þ0.01 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.8 0.188 0.986 141.5 310.2 140.8 90.4 0.0334 0.0383 3.09 6.41 6.32 6.41 0.0040 þ0.0003 0.41 þ0.52 þ1.00 þ1.52 w0.05/h (N ¼ 162, hr ¼ 47.4 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.72  0.08 (s ¼ 2.07  0.04) Ib: Hb ¼ 108.3  0.78 Mv; Hmax ¼ 98.0 þ 1.22 Mv; He ¼ 92.5 þ 1.64 Mv (N ¼ 92) Ib: r w 0.97  0.54 g/cm3 (a1 ¼ 0.058 km, a2 ¼ 4.54/s) From c and s: ~15,000 e

299

eV

Brief history: First reported by [1] with R.A. ¼ 4.1 , Decl. ¼ þ14.1 and Vg ¼ 57.4 km/s around lo ¼ 140.1 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29. August 28 (lo ¼ 155 )

1077 PIC d pi Cassiopeiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1872-Jan-08.0 TDB

Long-period comet, TJ ¼ þ0.18  0.43 Annual shower August 24eSeptember 1 (lo ¼ 150 e159 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 155.0 6.8 þ49.4 235.4 þ41.8 52.2 þ1.06 þ0.51 þ0.14 þ0.07 0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 19.0 0.704 0.963 94.2 248.0 155.0 42.6 eV 0.0169 0.0557 1.07 2.98 1.96 2.98 þ0.0020 0.0020 þ0.01 0.21 þ1.00 þ0.79 w0.03/h (N ¼ 62, hr ¼ 61.3 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.81  0.07 (s ¼ 2.12  0.03) Ib: Hb ¼ 108.9  0.87 Mv; Hmax ¼ 97.0 þ 2.28 Mv; He ¼ 92.8 þ 2.26 Mv (N ¼ 21) Ib: r w 0.62 g/cm3 (a1 ¼ 0.016 km, a2 ¼ 13.44/s) duncertain due to low N From c and s: w37,000 y C/1871 V1 (Tempel) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 161.3 0.691 0.996 98.3 242.9 148.9 31.8

Brief history: First reported here.

300

Northern apex

301

August

August 22 (lo ¼ 149 )

694 OMG d omicron Geminids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.52  0.69 Annual shower August 8eSeptember 9 (lo ¼ 135 e166 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 148.9 99.4 þ43.2 308.2 þ20.2 56.4 þ1.23 0.06 0.05 þ0.02 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.51 0.308 0.945 121.7 63.4 148.7 212.8 eV 0.0658 0.0555 4.39 9.16 6.89 9.16 þ0.0007 0.0020 þ0.07 þ0.04 þ1.00 þ1.07 w1/h (N ¼ 569, hr ¼ 31.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.76  0.31 (s ¼ 2.44  0.09) Ib: Hb ¼ 108.1  0.76 Mv; Hmax ¼ 100.8 þ 0.61 Mv; He ¼ 95.8 þ 1.11 Mv (N ¼ 305) III: Hb ¼ 98.2 þ 0.10 Mv; Hmax ¼ 94.3 þ 0.55 Mv; He ¼ 90.7 þ 0.36 Mv (N ¼ 27) Ib: low F ¼ 0.59, high KE ¼ 85 km: fragile meteoroids Ib: r < 1.0 g/cm3 (a1 ¼ 0.115 km, a2 ¼ 4.58/s) III: r w 4.6 g/cm3 (a1 ¼ 0.038 km, a2 ¼ 10.75/s) dpossibly Na poor/free From c and s: w40,000 y C/1299 B1 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.318 (1.000) 111.0 103.9 116.9 220.8

Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1299-Mar-31.8 TDB

Brief history: Shower is just adjacent, and perhaps related to #695. First reported by [1] from R.A. ¼ 116.1 , Decl. ¼ þ38.3 and Vg ¼ 58.9 km/s around lo ¼ 164 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409. August 31 (lo ¼ 157 )

918 TAG d theta Aurigids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.53  0.58 Annual shower August 24eSeptember 12 (lo ¼ 150 e169 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 157.9 93.1 34.2 295.4 þ1.04 þ0.02 0.12 a (AU) q (AU) e i ( ) 15.6 0.564 0.963 156.7 0.0274 0.0580 1.05 þ0.0027 0.0024 0.07 w0.08/h (N ¼ 90, hr ¼ 43.6 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.76  0.21 (s ¼ 2.44  0.08) Ib: Hb ¼ 111.5  2.21 Mv; Hmax ¼ 101.4 þ 0.61 Mv; Ib: r w 1.3 g/cm3 (a1 ¼ 0.083 km, a2 ¼ 3.95/s) From c and s: w53,000 y e

b ( ) þ10.9 þ0.05 u ( ) 96.0 4.59 þ0.27

Vg (km/s) 65.4 þ0.00 U ( ) 157.5 5.07 þ1.00

P ( ) 251.6 4.59 þ1.27

eV

He ¼ 95.7 þ 1.70 Mv (N ¼ 26) duncertain, low N

Brief history: First reported by [1] from R.A. ¼ 90.2 , Decl. ¼ þ34.3 and Vg ¼ 66.1 km/s around lo ¼ 154.7 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PPS 154, 21e29.

302

Northern apex

206 AUR e Aurigids.

303

August

August 23 (lo ¼ 149 )

545 XCA d xi Cassiopeiids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1872-Jan-08.0 TDB

Long-period comet, TJ ¼ þ0.08  0.36 Annual shower August 19e25 (lo ¼ 145 e151 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 148.8 4.2 þ47.4 237.5 þ41.0 53.2 þ0.72 þ0.29 0.24 0.01 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 24.0 0.724 0.970 97.1 244.9 148.8 33.9 eV 0.0153 0.0597 1.03 2.61 1.33 2.61 0.0030 þ0.0018 0.19 þ0.31 þ1.00 þ1.31 w0.07/h (N ¼ 47, hr ¼ 62.0 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 3.24  0.29 (s ¼ 2.28  0.09) Ib: Hb ¼ 108.2  0.46 Mv; Hmax ¼ 99.5 þ 1.84 Mv; He ¼ 94.4 þ 2.59 Mv (N ¼ 24) Ib: r w 0.44 g/cm3 (a1 ¼ 0.015 km, a2 ¼ 9.91/s) dlow N From c and s: w46,000 y; high dP/dlo versus i C/1871 V1 (Tempel) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 161.3 0.691 0.996 98.3 242.9 148.9 31.8

Brief history: Shower first identified by [1] from 13 meteors in Croatian Meteor Network and SonotaCo data that had orbits similar to C/1871 V1 based on a D-criterion. Wide distribution of radiants with R.A. ¼ 7.1 , Decl. ¼ þ49.9 and Vg ¼ 52.7 km/s around lo ¼ 154.3 . [2] confirmed the detection. A more compact cluster identified by [3]. Here we note that a group of similar orbits but with lower entry speed occur slightly later (now #1077). Name and number by [1]. References: [1] Segon D., et al. (2014) JIMO 42, 57e64; [2] Kornos L., et al. (2014) In: Meteoroids 2013. Eds.: T. J. Jopek, F. J. M. Rietmeijer, J. Watanabe, I. P. Williams, Poznan: A.M. University Press, p. 225e233; [3] Jenniskens P., et al. (2021) Icarus 365, article id. 114469. August 29 (lo ¼ 156 )

815 UMS d August Ursae Majorids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Mellish comet type shower, TJ ¼ þ0.80  0.33 Annual shower August 20eSeptember 7 (lo ¼ 147 e165 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 155.7 147.1 þ62.6 327.2 þ1.83 0.62 þ0.47 a (AU) q (AU) e i ( ) 10.2 0.659 0.945 65.0 0.0340 0.0804 2.52 0.0029 0.0043 0.35 0.06/h (N ¼ 77, hr ¼ 27.4 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.63  0.29 (s ¼ 2.05  0.12) Ib: Hb ¼ 105.4  0.79 Mv; Hmax ¼ 96.9 þ 1.02 Mv; Ib: r w 1.6 g/cm3 (a1 ¼ 0.218 km, a2 ¼ 2.32/s) From c and s: w25,000 y e

b ( ) þ46.6 0.15 u ( ) 106.5 4.66 0.21

Vg (km/s) 41.5 0.05 U ( ) 155.7 5.11 þ1.00

P ( ) 262.4 4.66 þ0.79

eV

He ¼ 91.5 þ 1.32 Mv (N ¼ 28) e uncertain low N

Brief history: First identified by [1] from 21 meteors of the BRAMON, EDMOND and SonotaCo networks with R.A. ¼ 146.3 , Decl. ¼ þ63.9 and Vg ¼ 41.2 km/s around lo ¼ 154.7 . Weak shower. Name and number by [1]. References: [1] Amaral L. S., et al. (2020) JIMO 48, 69e88.

Northern apex

206 AURdAurigids

304

August

305

August 24 (lo ¼ 151 )

693 ANP d August nu Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.56  0.43 Annual shower August 8eSeptember 9 (lo ¼ 135 e167 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 150.7 56.1 þ41.0 272.6 þ20.7 67.3 þ1.07 þ0.12 0.14 0.07 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 13.7 1.007 0.926 144.6 172.6 150.7 323.3 eV 0.0023 0.110 0.88 2.08 7.92 2.08 þ0.0002 þ0.0002 þ0.13 þ0.43 þ1.00 þ1.43 w0.1/h (N ¼ 338, hr ¼ 51.4 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.01  0.07 (s ¼ 2.20  0.03) I: Hb ¼ 115.2  1.24 Mv; Hmax ¼ 106.5 þ 0.73 Mv; He ¼ 99.0 þ 1.54 Mv (N ¼ 159) III: Hb ¼ 98.6  0.05 Mv; Hmax ¼ 95.3 þ 0.62 Mv; He ¼ 88.0 þ 1.29 Mv (N ¼ 8) I: low F ¼ 0.54, fragile meteoroids I: r  0.38 g/cm3 (a1 ¼ 0.064 km, a2 ¼ 5.84/s), lower if fragile dNa chondritic III: possibly Na poor/free Mg0.84 Fe0.34 Na0.069 (N ¼ 1) From c and s: w60,000 y e

Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source:

Brief history: Well defined shower, but found on top of diffuse #372 (perhaps introducing wrongly identified meteors into shower sample). Points scatter to q > 1.02 AU at lo > 160. First reported to MDC by [1], but not published as it was deemed too faint a detection, then found again by [2] from R.A. ¼ 54.7 , Decl. ¼ þ40.7 and Vg ¼ 67.1 km/s around lo ¼ 149.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409; [2] Jenniskens P., et al. (2018) PPS 154, 21e29. September 13 (lo ¼ 170 ) 695 APA d August psi Aurigids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.15  0.64 Annual shower August 15eOctober 28 (lo ¼ 143 e215 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 170.5 123.0 þ36.8 306.1 þ16.5 59.4 þ1.04 0.21 0.09 0.00 þ0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.10 0.323 0.961 133.8 67.2 170.5 237.0 eV 0.0586 0.0498 5.1 8.36 14.83 8.36 þ0.0021 þ0.0001 þ0.13 þ0.28 þ1.00 þ1.28 w2/h (N ¼ 1372, hr ¼ 32.4 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.81  0.23 (s ¼ 2.45  0.07) Two components (IIb has low He, Ke < 79, like III): Ib: Hb ¼ 109.7  1.03 Mv; Hmax ¼ 100.8 þ 0.90 Mv; He ¼ 96.1 þ 1.44 Mv (N ¼ 772) IIb: Hb ¼ 99.6  0.89 Mv; Hmax ¼ 94.8  0.14 Mv; He ¼ 89.8 þ 0.22 Mv (N ¼ 45) Ib: r w 0.79  0.30 g/cm3 (a1 ¼ 0.068 km, a2 ¼ 5.74/s) dpossibly Na poor/free IIb: r w 1.2  0.5 g/cm3 (a1 ¼ 0.174 km, a2 ¼ 8.97/s) From c and s: w47,000 y e

Brief history: Just next to #694, possibly related. First reported by [1] from R.A. ¼ 95.6 , Decl. ¼ þ42.1 and Vg ¼ 53.6 km/s around lo ¼ 146.0 , early in the activity window. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

306

Northern apex

August

August 26 (lo ¼ 153 )

701 BCE d beta Cepheids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.85  0.41 Annual shower, possibly episodic Higher N in 2014 (N ¼ 19) and 2016 (N ¼ 21) August 24e29 (lo ¼ 150 e156 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 153.0 324.0 þ75.8 259.2 þ71.2 39.5 0.36 þ0.18 0.00 0.00 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.00 1.006 0.933 65.6 187.9 153.0 340.9 0.0014 0.0781 1.23 1.28 0.80 1.28 0.0004 þ0.0066 þ0.08 þ0.20 þ1.00 þ1.20 w0.3/h (N ¼ 112, hr ¼ 50.3 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.03  0.05 (s ¼ 1.77  0.03) Component I has high He: I: Hb ¼ 106.6  1.14 Mv; Hmax ¼ 99.5 þ 0.45 Mv; He ¼ 93.9 þ 1.29 Mv (N ¼ 58) I: low F ¼ 0.56, fragile meteoroids I: r  0.28  0.08 g/cm3 (a1 ¼ 0.044 km, a2 ¼ 5.70/s), less if fragile Mg1.03 Fe0.95 Na0.064 (N ¼ 1), chondritic From c and s: w10,000 y e

Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source:

307

eV

Brief history: Narrow shower. First reported by [1] from R.A. ¼ 325.4 , Decl. ¼ þ75.8 and Vg ¼ 39.8 km/s around lo ¼ 153.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409. August 28 (lo ¼ 155 )

523 AGC d August gamma Cepheids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.97  0.35 Annual shower August 20eSeptember 3 (lo ¼ 147 e161 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 154.6 358.9 þ76.7 264.1 þ63.4 43.7 þ0.55 þ0.20 0.47 0.03 þ0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.53 1.006 0.882 75.6 187.2 155.0 342.4 0.0039 0.100 2.00 4.22 2.92 4.22 0.0005 þ0.0087 þ0.13 þ0.50 þ1.00 þ1.50 w0.4/h (N ¼ 744, hr ¼ 50.1 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.03  0.05 (s ¼ 1.77  0.03); rich in bright meteors, deficient in faint [3] Ib: Hb ¼ 105.6  0.89 Mv; Hmax ¼ 97.2 þ 1.02 Mv; He ¼ 90.3 þ 1.63 Mv (N ¼ 307) III: Hb ¼ 93.2  0.25 Mv; Hmax ¼ 87.6 þ 1.39 Mv; He ¼ 83.2 þ 1.00 Mv (N ¼ 19) Ib: low F ¼ 0.55, fragile meteoroids Ib: r  0.82  0.23 g/cm3 (a1 ¼ 0.084 km, a2 ¼ 5.09/s), lower if fragile III: Possibly Na poor/free From c: w8000 y and s: w32,000 y, sU < su e

Lightcurve shape: Meteoroid density: Age: Source:

eV

Brief history: First reported by [1] from 44 meteors with R.A. ¼ 358 , Decl. ¼ þ76.4 , Vg ¼ 44.0 km/s around lo ¼ 155.1 . Confirmed by [2]. From past data, [3] only found one photographed orbit and two radar orbits that might belong to this shower. Shower arrives from q > rE before lo ¼ 154 . Name and number by [1]. References: [1] Andreic Z., et al. (2013) JIMO 41, 103e108; [2] Jenniskens P., et al. (2016) Icarus 266, 355e370; [3] Roggemans P. (2018) eMeteorNews 3, 73e78.

308

Northern apex

August

August 28 (lo ¼ 155 )

580 CHA d chi Andromedids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.00  0.45 Annual shower August 21eSeptember 7 (lo ¼ 147 e165 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 155.1 26.4 þ45.7 247.0 þ32.1 59.0 þ1.17 þ0.25 þ0.16 þ0.11 þ0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.06 0.756 0.917 117.6 241.8 155.1 37.7 0.0377 0.103 3.65 5.06 3.87 5.06 0.0009 þ0.0021 þ0.19 þ0.05 þ1.00 þ1.05 w0.3/h (N ¼ 526, hr ¼ 66.6 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.23  0.13 (s ¼ 2.27  0.05) Ib: Hb ¼ 108.5  0.69 Mv; Hmax ¼ 99.9 þ 1.00 Mv; He ¼ 94.3 þ 1.69 Mv (N ¼ 243) III: Hb ¼ 96.6 þ 0.36 Mv; Hmax ¼ 92.7 þ 1.03 Mv; He ¼ 89.0 þ 1.08 Mv (N ¼ 30) Ib: r w 0.81  0.54 g/cm3 (a1 ¼ 0.030 km, a2 ¼ 10.12/s) III: Possibly Na poor/free w100,000 y [2]; from c and s: w65,000 y; high dP/dlo versus i C/1992 W1 (Ohshita) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 95.1 0.665 0.993 115.1 310.2 138.4 88.6

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1992-Dec-18.0 TDB

309

eV

Brief history: This shower was first reported by [1] from CMN and SonotaCo video data with 29 meteors arriving from R.A. ¼ 23.9 , Decl. ¼ þ45.0 and Vg ¼ 58.9 km/s around lo ¼ 154 . Association with 1992 W1 by [2], from evolved stream, with predicted radiant for “Filament F2” at R.A. ¼ 26.7  2.2 , Decl. ¼ þ46.9  0.6 and Vg ¼ 59.2  0.6 km/s around lo ¼ 157.5  2.1 . However, “Filament F1” not detected. Name and number by [1]. References: [1] Gural P., et al. (2014) JIMO 42, 132e138; [2] Hajduková M., Neslusan L. (2020) Icarus 351, id. 113960. September 2 (lo ¼ 159 )

376 ALN d August Lyncids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magnitude distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.53  0.28 Annual shower July 31eSeptember 22 (lo ¼ 127 e179 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 159.1 143.0 þ48.4 329.5 þ31.7 44.8 þ1.21 0.09 0.08 þ0.19 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 23.9 0.382 0.982 66.5 75.2 159.0 234.2 eV 0.0386 0.0278 2.74 4.66 11.9 4.66 þ0.0035 þ0.0001 þ0.16 þ0.43 þ1.00 þ1.43 32.7 0.438 0.987 57.6 81.8 135.0 216.8 e R[1] w0.4/h (N ¼ 425, hr ¼ 19.2 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.66  0.04 (s ¼ 2.06  0.02) Ib: Hb ¼ 107.5  0.94 Mv; Hmax ¼ 98.1 þ 1.07 Mv; He ¼ 92.9 þ 1.70 Mv (N ¼ 140) II: Hb ¼ 101.3  1.01 Mv; Hmax ¼ 95.1 þ 1.01 Mv; He ¼ 90.7 þ 0.89 Mv (N ¼ 39) Ib: r w 2.3  0.7 g/cm3 (a1 ¼ 0.092 km, a2 ¼ 2.05/s) II: r w 3.5 g/cm3 (a1 ¼ 0.323 km, a2 ¼ 2.74/s) dlikely Na poor/free From c: w20,000 y, from s (tail): w55,000; Drift in radiant: sU > su C/1402 D1 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.380 (1.000) 55.0 91.0 126.0 217.0 From c and s: w38,000 y

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1992-Dec-18.0 TDB Age:

310

Northern apex

August

311

Brief history: Shower first reported from CMOR radar observations by [1] from 443 meteors that arrived from R.A. ¼ 119.8 , Decl. ¼ þ55.1 with Vg ¼ 41.7 km/s around lo ¼ 135.0 , corresponding to R.A. ¼ 149.0 , Decl. ¼ þ46.2 at lo ¼ 159.1 . Unlike other radar-detected showers, the magnitude distribution index is relatively low. Unusual longperiod comet orbit. The video detection here is strong. Name and number by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81. August 28 (lo ¼ 156 )

1137 AMP d August mu Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.42  0.67 Annual shower August 18eSeptember 6 (lo ¼ 145 e164 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 155.5 63.2 þ46.1 274.4 þ24.7 65.7 þ1.20 þ0.00 0.10 0.16 þ0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.2 0.999 0.911 137.5 167.5 155.2 322.4 0.0037 0.121 1.24 2.04 4.61 2.04 þ0.0000 0.0022 þ0.27 þ0.29 þ1.00 þ1.29 w0.07/h (N ¼ 180, hr ¼ 50.1 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.63  0.08 (s ¼ 2.05  0.03) Ib: Hb ¼ 112.0  1.65 Mv; Hmax ¼ 103.4 þ 0.89 Mv; He ¼ 97.9 þ 1.54 Mv (N ¼ 93) III: Hb ¼ 98.2 þ 0.11 Mv; Hmax ¼ 92.6 þ 2.10 Mv; He ¼ 88.0 þ 2.32 Mv (N ¼ 7) Ib: r w 0.57  0.25 g/cm3 (a1 ¼ 0.038 km, a2 ¼ 8.70/s) III: Possibly Na poor/free From c and s: w44,000 y e

Meteoroid density: Age: Source:

eV

Brief history: First detected here. Weak shower on top of strong background from shower #372. August 30 (lo ¼ 156 )

1134 PIE d pi Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.26  0.71 Annual shower August 24eSeptember 6 (lo ¼ 150 e163 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 155.8 41.8 þ40.9 256.1 þ23.8 64.8 þ1.10 þ0.26 0.05 0.01 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.25 0.875 0.906 137.0 224.5 155.8 20.5 eV 0.0161 0.115 1.64 4.16 3.12 4.16 0.0022 0.0029 þ0.27 þ0.35 þ1.00 þ1.35 w0.07/h (N ¼ 75, hr ¼ 67.9 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.37  0.30 (s ¼ 2.32  0.10) Ib: Hb ¼ 111.2  0.57 Mv; Hmax ¼ 102.3 þ 1.40 Mv; He ¼ 97.2 þ 2.07 Mv (N ¼ 44) Ib: r w 0.30  0.13 g/cm3 (a1 ¼ 0.068 km, a2 ¼ 6.55/s) duncertain due to low N From c and s: w69,000 y e

Brief history: First detected by [1] and registered in Working List, but ultimately not reported as shower was deemed too weak. Found back here as very weak shower on top of strong background from northern apex source. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

312

Northern apex

September

313

September 8 (lo ¼ 166 ) 205 XAU d xi Aurigids Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2003-Feb-10.0 TDB

Long-period comet, TJ ¼ þ0.07  0.34 Annual shower e September 5e10 (lo ¼ 162 e168 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 165.9 111.6 þ61.4 297.5 þ39.1 55.8 þ1.30 0.20 0.17 0.08 þ0.01 a (AU) q (AU) E i ( ) u ( ) U ( ) P ( ) 15.4 0.775 0.949 104.2 121.4 165.9 288.1 eV 0.0272 0.0761 1.92 4.65 1.25 4.65 þ0.0005 0.0047 þ0.18 þ0.01 þ1.00 þ1.01 w0.3/h (N ¼ 72, hr ¼ 37.0 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.19  0.15 (s ¼ 2.26  0.05) Ib: Hb ¼ 109.4  0.66 Mv; Hmax ¼ 101.9 þ 0.70 Mv; He ¼ 97.7 þ 1.13 Mv (N ¼ 36) duncertain, low N Ib: r w 1.6 g/cm3 (a1 ¼ 0.066 km, a2 ¼ 4.60/s) From c and s: w58,000 y; high dP/dlo versus i Earth seems to be passing through core of stream (sU < su) C/2002 Y1 (Juels-Holvorcem) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 250.6 0.714 0.997 103.8 128.8 166.2 295.0

Brief history: Shower possibly first identified by [1] based on three photographic orbits compiled by [2], with meteors radiating from R.A. ¼ 93.5 , Decl. ¼ þ62.6 and Vg ¼ 56.9 km/s during lo ¼ 157.5e160.4 , corresponding to R.A. ¼ 102.5 , Decl. ¼ þ61.2 at lo ¼ 165.9 . This is 5 further East. Source identified by [3], but shower incorrectly identified as #705. Name and number by [1] adopted here. References: [1] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 723; [2] Porubcan V., Kornos V. (2002) ESA-SP 500, 177e180; [3] Jenniskens P., et al. (2020) Icarus 365, article id. 114469.

September 17 (lo ¼ 175 ) 874 PXS d September xi Perseids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source:

Long-period comet, TJ ¼ 0.65  0.43 Annual shower September 13e24 (lo ¼ 170 e181 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 175.2 60.1 þ38.0 250.5 þ17.1 65.9 þ1.11 þ0.02 0.10 0.16 þ0.16 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 19.8 0.728 0.966 147.1 244.0 175.2 59.1 0.0212 0.0778 1.04 3.94 2.35 3.94 0.0016 0.0088 þ0.31 þ0.01 þ1.00 þ1.01 w0.1/h (N ¼ 243, hr ¼ 55.1 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.15  0.07 (s ¼ 1.83  0.04) I: Hb ¼ 114.5  1.12 Mv; Hmax ¼ 105.8 þ 0.78 Mv; He ¼ 98.5 þ 1.50 Mv (N ¼ 122) IIb: Hb ¼ 103.3  2.47 Mv; Hmax ¼ 98.3  0.66 Mv; He ¼ 93.4  0.08 Mv (N ¼ 10) I: low F ¼ 0.54, fragile meteoroids I: r  0.51  0.22 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 8.28/s), lower if fragile Mg2.06 Fe0.80 Na0.086 (N ¼ 1) From c: w14,000, from s: w37,000 y; sU < su e

eV

Brief history: First reported by [1] at R.A. ¼ 59.8 , Decl. ¼ þ37.9 with Vg ¼ 66.5 km/s around lo ¼ 174.8 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) Planetary & Space Sci 154, 21e29.

314

Northern apex

September

315

September 23 (lo ¼ 180 ) 424 SOL d September-October Lyncids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.27  0.62 Annual shower September 17e30 (lo ¼ 174 e187 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 180.3 124.0 þ47.4 294.9 þ26.8 61.9 þ1.33 0.23 þ0.04 þ0.01 0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 16.1 0.697 0.955 126.1 111.8 180.3 292.0 eV 0.0267 0.076 1.67 4.66 2.83 4.66 0.0013 0.0019 0.06 0.17 þ1.00 þ0.83 w0.2/h (N ¼ 81, hr ¼ 39.4 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.83  0.28 (s ¼ 2.13  0.10) I: Hb ¼ 112.5  1.71 Mv; Hmax ¼ 103.8 þ 0.39 Mv; He ¼ 98.4 þ 1.46 Mv (N ¼ 38) I: r w 0.65 g/cm3 (a1 ¼ 0.034 km, a2 ¼ 6.53/s) duncertain due to low N From c and s: w44,000 y e

Brief history: Shower was first detected by [2], but name and number by [1]. First named by [1] from single-station meteors radiating from R.A. ¼ 110 , Decl. ¼ þ48 with Vg ¼ 68 km/s around lo ¼ 186 , but with a wider activity interval than identified here. [3] pointed out that this position is identical to shower #81 (September Lyncids). [2] used this name instead for a shower at R.A. ¼ 121.0 , Decl. ¼ þ47.8 with Vg ¼ 62.4 km/s around lo ¼ 178, the same cluster that is identified here. Activity curve from video data shown in Fig. 6.7.

FIG 6.7

ZHR profile (•), vertical scale uncertain.

References: [1] Rendtel J., Molau S. (2010) JIMO 38, 161e166; [2] Jenniskens P., et al. (2016) Icarus 266, 331e354; [3] Koseki M. (2020) eMeteorNews 5, 93e111.

September 9 (lo ¼ 167 ) 208 SPE d September epsilon Perseids Dynamic type: Shower type: Years of outbursts:

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo):

Long-period comet, TJ ¼ þ0.50  0.38 Annual shower, episodic outbursts of bright meteors (1877e1880, 1898, 1911), 2008: lo ¼ 166.907  0.013 , N ¼ 11, W ¼ 0.096 [7] 2009: lo ¼ 167.009  0.012 , N ¼ 37, W ¼ 0.16 2013: lo ¼ 167.196  0.003 , ZHR ¼ 32  8, W ¼ 0.038 [8,19]; c ¼ 1.45  0.15 [14] 2019: lo ¼ 166.799  0.007 , N ¼ 93, W ¼ 0.160 2020: lo ¼ 166.805  0.007 , N ¼ 22, W ¼ 0.081 , c ¼ 3.60  0.27 September 2eNovember 3 (lo ¼ 160 e220 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 167.4 48.2 þ39.6 249.0 þ20.6 64.3 þ1.14 þ0.01 0.08 0.14 þ0.01

316

Northern apex

September

317

September 9 (lo ¼ 167 )

208 SPE d September epsilon Perseids (cont.)

Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

q (AU) e i ( ) u ( ) U ( ) P ( ) 0.708 0.952 139.5 247.2 167.4 55.6 eV 0.0337 0.0932 1.67 6.00 11.02 6.00 0.0033 þ0.0000 þ0.21 þ0.38 þ1.00 þ1.38 N ¼ 4350 (hr ¼ 61.3 , m(Mv ¼ 0) ¼ 0.02 g) Annual: 5/h [10]; 3.1/h [13]; 4/h [18] Annual: c ¼ 2.43  0.03 (s ¼ 1.96  0.01); 2.6 [11]; 2.46 [13]; 2.50  0.25 [14] Ib: Hb ¼ 112.0  1.43 Mv; Hmax ¼ 102.6 þ 1.20 Mv; He ¼ 97.4 þ 1.68 Mv (N ¼ 1824) III: Hb ¼ 99.9 þ 0.96 Mv; Hmax ¼ 94.8 þ 0.47 Mv; He ¼ 89.8 þ 0.33 Mv (N ¼ 41) Ib: r w 0.48  0.15 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 7.49/s) dNa poor III: r w 2.2 g/cm3 (a1 ¼ 0.013 km, a2 ¼ 17.19/s) rairV2: 0.029  0.003 MPa [17]; 0.02e0.09 MPa, PE: 37% II, 56% IIIA, 7% IIIB [9] Mechanical strength w 100 Pa if rotation caused fragment cluster [10] Mg0.99 Fe0.49 Na0.071 (N ¼ 5); chondritic Na/Fe, Mg/Fe (N ¼ 2) [17]; H [9] From c (core): w27,000 y, while s (tail): w70,000 (sU > su) e

Meteoroid density: Strength: Spectroscopy: Age: Source:

a (AU) 16.1

Brief history: This annual shower peaks in early September, but has a long tail of activity into November (Fig. 6.8), during which P increases, q decreases, and i increases. First found by Shiaparelli from 1867 to 1870 observations by G. Zezioli at Bergamo, Italy, with radiant at R.A. ¼ 60 ,  Decl. ¼ þ32 (Equinox of date) on September 8 [14]. Tupman also saw the shower during September 7e15 from R.A. ¼ 66 , Decl. ¼ þ40 . [14] described it as a “prominent September shower”, placing radiant at R.A. ¼ 60 , Decl. ¼ þ37 (Equinox of date) during September 5e12, and naming the shower after star ε Persei. [1] observed 238 meteors during September 4e16, 1877, some radiating from FIG 6.8 ZHR profile. R.A. ¼ 61 , Decl. ¼ þ36 (Equinox of date). “September Perseids” described as “swift and much brighter than the average; they nearly all left streaks”. [2] detected “xi Perseids” (her number 46) among 554 photographed fireballs, with a radiant at R.A. ¼ 54.8 , Decl. ¼ þ36.2 and Vg ¼ 67.1 km/s around lo ¼ 170.1 (September 9e17). The shower later identified from 3 [3], 10 [4], and 8 [5] photographed orbits. Visual analysis by [12,13]. Confirmed from low-light video observations by [6]. SonotaCo network detected 2008 outburst [7]. Detected by EDMOND network [8] and also by European Network from R.A. ¼ 47.67  0.04, Decl. ¼ þ39.493  0.013 [9]. Reported here are outbursts in 2009 (SonotaCo), 2019 (CAMS BeNeLux), and 2020 (CAMS Chile and Florida). [10] observed a September epsilon Perseid that fragmented 2e3 days prior to entering Earth’s atmosphere. [9] measured a ¼ 80  27 AU for the mean orbit of 2013-outburst fireballs. Model of 1-revolution dust trail evolution of a long-period comet [16] starting with 2008 crossing predicted correctly 2013 return [15]. Name by [14], number by [5]. References: [1] Denning W. F. (1882) The Observatory 5, 262e265; [2] Terentjeva A. K. (1989) JIMO 17, 242e245; [3] Porubcan V., Gavajdová M. (1994) PSS 42, 151e155; [4] Rendtel J. (1992) In: Meteoroids and their Parent Bodies. Eds: J. Stohl, I. P. Williams, Bratislava: Astron. Inst. Slovak Acad. Sci., pp 185e188; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [6] Kanamori T. (2009) JIMO 37, 55e62; [7] Jenniskens P. (2008) CBET 1501, Ed.: D. W. E. Green, Cambridge: CBAT, 1 pp; [8] Gajdos S., et al.

318

Northern apex

208 SPEdSeptember epsilon Perseids

September

319

JIMO 42, 48e56; [9] Shrbeny L., Spurny P. (2019) AA 629, A137eA146; [10] Koten P., et al. (2017) AA 600, A74eA78; [11] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [12] Trigo-Rodriguez J. M. (1989) JIMO 17, 156e158; [13] Dubietis A., Arlt R. (2002) JIMO 30, 168e174; [14] Denning W. F. (1878) MNRAS 39, 22e31; [15] Rendtel J., et al. (2014) JIMO 42, 40e47; [16] Lyytinen E., Jenniskens P. (2003) Icarus 162, 443e452; [17] Madiedo J. M., et al. (2018) MNRAS 480, 2501e2507; [18] Molau S., et al. (2019) JIMO 47, 160e162; [19] Jenniskens P. (2013) CBET 3652, Ed.: D.W.E. Green, Cambridge: CBAT, 1pp. September 17 (lo ¼ 169 ) 705 UYL d UY Lyncids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 1995-Oct-10.0 TDB

FIG 6.9

Long-period comet, TJ ¼ 0.11  0.35 Annual shower September 12e21 (lo ¼ 164 e178 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 169.3 111.5 þ55.9 295.0 þ33.6 58.9 þ1.84 0.01 þ0.22 þ0.19 0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 14.2 0.756 0.945 114.5 119.0 169.3 288.4 0.0249 0.0706 1.76 4.16 2.78 4.16 0.0021 0.0006 0.49 0.27 þ1.00 þ0.73 w0.5/h (N ¼ 574, hr ¼ 37.3 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.50  0.06 (s ¼ 2.00  0.02) I: Hb ¼ 111.4  0.83 Mv; Hmax ¼ 104.0 þ 0.78 Mv; He ¼ 96.7 þ 1.51 Mv (N ¼ 214) II: Hb ¼ 102.4  1.15 Mv; Hmax ¼ 97.3  0.27 Mv; He ¼ 92.9 þ 0.71 Mv (N ¼ 20) I: low F ¼ 0.50, fragile meteoroids r w 1.02  0.50 g/cm3 (N ¼ 1) [4] I: r  0.75  0.34 g/cm3 (a1 ¼ 0.078 km, a2 ¼ 4.86/s), lower if fragile II: Possibly Na poor/free From c and s: w38,000 y 109P/SwifteTuttle a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 26.1 0.960 0.963 113.5 153.0 139.4 292.4

ZHR profile.

eV

Brief history: Shower recognized by [1] from single station IMO Video Meteor Network data with radiant R.A. ¼ 107.4 , Decl. ¼ þ55.0 and Vg ¼ 60.0 km/s during lo ¼ 165e172 . However, the shower was incorrectly assigned to #81, the September Lyncids, which is detected during lo ¼ 186e189 (article contains two entries for #81). Confirmed in double station observations by [2] and given name and number #705. Again adopted the wrong #81 in the 2018 CAMS Shower Lookup Table (http://cams. seti.org/FDL/). [3] also assigned to #81 and used #705 for the weaker shower just north of it. Here, we adopt name and number by [2]. Activity curve shown in Fig. 6.9. Link to 109P by [5].

References: [1] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [2] Jenniskens P., et al. (2016) Icarus 266, 384e409; [3] Jenniskens P., et al. (2020) Icarus 365, article id. 114469; [4] Kikwaya Eluo J.-B. (2011) Bulk density of small meteoroids. PhD Thesis, London: University of Western Ontario, p. 232; [5] Neslusan L., Hajduková M. (2022) Icarus 382, id.115015.

320

Northern apex

September

321

September 10 (lo ¼ 168 ) 416 SIC d September iota Cassiopeiids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.55  0.39 Annual shower August 24eSeptember 19 (lo ¼ 150 e176 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 167.5 7.4 þ64.1 252.1 þ46.5 52.8 þ1.14 þ0.34 0.11 þ0.05 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 13.0 0.918 0.876 97.5 216.0 167.5 23.3 eV 0.0233 0.144 3.80 5.68 6.02 5.68 0.0008 þ0.0038 0.09 þ0.06 þ1.00 þ1.06 w0.3/h (N ¼ 748, hr ¼ 59.0 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.78  0.18 (s ¼ 2.11  0.07) Ib: Hb ¼ 109.2  1.07 Mv; Hmax ¼ 101.8 þ 0.54 Mv; He ¼ 96.2 þ 1.27 Mv (N ¼ 363) III: Hb ¼ 97.9  0.79 Mv; Hmax ¼ 91.2 þ 0.56 Mv; He ¼ 85.3 þ 1.82 Mv (N ¼ 56) Ib: low F ¼ 0.57, fragile meteoroids Ib: r  0.54 g/cm3 (a1 ¼ 0.044 km, a2 ¼ 8.22/s), lower if fragile III: r w 2.1 g/cm3 (a1 ¼ 0.018 km, a2 ¼ 15.48/s) dpossibly Na free From c and s: w73,000 y; high dP/dlo versus i e

Brief history: Shower has abrupt end. First recognized in cluster of single-station video observations of the IMO Video Meteor Network by [1] with R.A. ¼ 36.7 , Decl. ¼ þ65 and Vg ¼ 50 km/s around lo ¼ 169 . Confirmed from double station video meteors by [2]. Name and number by [1]. References: [1] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [2] Jenniskens P., et al. (2016) Icarus 266, 384e409. September 19 (lo ¼ 176 ) 713 CCR d chi Cancrids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Age: Source:

Long-period comet, TJ ¼ 0.06  0.54 Annual shower September 4e30 (lo ¼ 161 e187 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 176.5 119.0 þ29.5 299.3 þ9.0 63.8 þ0.97 0.20 0.12 0.04 þ0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.49 0.433 0.952 158.5 80.6 176.5 257.1 eV 0.0052 0.066 3.96 7.63 5.87 7.63 þ0.0033 0.0001 þ0.16 þ0.40 þ1.00 þ1.40 w0.5/h (N ¼ 282, hr ¼ 36.3 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.44  0.09 (s ¼ 2.34  0.03) Component II has high end height, Ke > 82: Ib: Hb ¼ 112.0  1.49 Mv; Hmax ¼ 103.6 þ 0.38 Mv; He ¼ 98.7 þ 0.87 Mv (N ¼ 124) II: Hb ¼ 105.9  1.65 Mv; Hmax ¼ 99.9  0.54 Mv; He ¼ 95.5  0.10 Mv (N ¼ 32) III: Hb ¼ 98.4 þ 0.13 Mv; Hmax ¼ 94.7 þ 1.14 Mv; He ¼ 91.3 þ 1.07 Mv (N ¼ 11) Ib: r w 0.58 g/cm3 (a1 ¼ 0.043 km, a2 ¼ 6.85/s) II: r w 0.59 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 7.02/s) dpossibly Na poor III: possibly Na free From c and s: w46,000 y e

Brief history: Broad distribution of type II lightcurves. First reported by [1] at R.A. ¼ 125.6 , Decl. ¼ þ29.2 with Vg ¼ 63.8 km/s around lo ¼ 181.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

322

Northern apex

323

September

September 28 (lo ¼ 185 ) 81 SLY d September Lyncids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age:

Long-period comet, TJ ¼ 0.60  0.47 Annual shower September 26eOctober 1 (lo ¼ 183 e188 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 185.5 110.6 þ47.9 279.4 þ25.5 65.5 þ1.30 0.06 0.04 þ0.07 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 12.4 0.950 0.927 135.3 153.0 185.5 338.4 0.0058 0.118 0.87 2.36 1.09 2.36 0.0001 0.0024 0.17 0.01 þ1.00 þ0.99 w2/h (N ¼ 69, hr ¼ 45.2 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 2.98  0.25 (s ¼ 2.18  0.09) Ib: Hb ¼ 113.5  0.71 Mv; Hmax ¼ 104.9 þ 1.24 Mv; He ¼ 99.9 þ 1.92 Mv (N ¼ 39) Ib: F ¼ 0.51: fragile Ib: r  0.46 g/cm3 (a1 ¼ 0.085 km, a2 ¼ 4.47/s), lower if fragile From c and s: w50,000 y; Earth passing through core of stream (sU < su)

eV

Brief history: Shower first recognized by [1] from two photographed meteors HV4622 and HV4683 on September 28, 1952, with mean radiant at R.A. ¼ 110 , Decl. ¼ þ48 and Vg ¼ 66 km/s, called “Lyncids”, during lo ¼ 184e185 . Included in [2]. Confirmed by [3] (Table 6) from single station IMO Video Meteor Network data with radiant R.A. ¼ 110.2 , Decl. ¼ þ48.4 and Vg ¼ 60.0 km/s during lo ¼ 186e189 . Name and number by [2]. References: [1] Lindblad B. A. (1971) SCoA 12, 14e24; [2] Jenniskens P. (2006) Meteor Shower and their Parent Comets. Cambridge: CUP, 790 pp; [3] Molau S., Rendtel J. (2009) JIMO 37, 98e121. October 4 (lo ¼ 191 )

556 PTA d phi Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ 0.14  0.38 Annual shower September 13eOctober 15 (lo ¼ 169 e209 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 190.6 60.8 þ28.6 235.3 þ7.9 60.9 þ0.96 þ0.15 0.14 0.02 0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 18.8 0.265 0.976 156.6 299.3 189.2 127.9 eV 0.066 0.055 4.08 9.33 9.13 9.33 0.0032 þ0.0005 0.08 þ0.40 þ1.00 þ1.40 w0.5/h (N ¼ 1551, hr ¼ 63.3 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.18  0.31 (s ¼ 2.25  0.10) Ib: Hb ¼ 109.5  0.84 Mv; Hmax ¼ 99.4 þ 1.21 Mv; He ¼ 94.2 þ 1.63 Mv (N ¼ 919) III: Hb ¼ 99.1  0.69 Mv; Hmax ¼ 93.4 þ 0.59 Mv; He ¼ 88.6 þ 0.82 Mv (N ¼ 138) Ib: r w 0.70  0.43 g/cm3 (a1 ¼ 0.058 km, a2 ¼ 7.70/s) III: r w 2.2  0.7 g/cm3 (a1 ¼ 0.019 km, a2 ¼ 18.38/s) dpossibly Na poor From c and s: w30,000 y e

Meteoroid density: Age: Source:

[see plate on p. 338]

Brief history: First detected by [1] from 22 video meteors by the Croatian Meteor Network radiating from R.A. ¼ 63.9 , Decl. ¼ þ29.1 with Vg ¼ 60.2 km/s around lo ¼ 193 . Confirmed from SonotaCo, CAMS and EDMOND data by [2], who found activity period lo ¼ 175 e206 centered on 190 . Name and number by [1]. References: [1] Andreic Z., et al. (2014) JIMO 42, 90e97; [2] Roggemans P. (2019) eMeteorNews 4, 148e154.

324

Northern apex

October

325

October 2 (lo ¼ 189 )

555 OCP d October gamma Camelopardalids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.57  0.32 Annual shower September 23eOctober 13 (lo ¼ 180 e200 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 188.5 41.4 þ68.0 236.1 þ48.7 48.9 þ1.66 þ0.30 þ0.03 þ0.00 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 10.7 0.791 0.926 85.4 235.9 188.5 64.3 eV 0.038 0.088 2.61 6.05 4.21 6.05 þ0.0011 þ0.0003 þ0.03 0.09 þ1.00 þ0.91 w0.4/h (N ¼ 513, hr ¼ 54.4 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 3.00  0.12 (s ¼ 2.19  0.04) Ib: Hb ¼ 108.0  0.87 Mv; Hmax ¼ 99.0 þ 1.30 Mv; He ¼ 94.0 þ 1.71 Mv (N ¼ 242) III: Hb ¼ 96.2  0.24 Mv; Hmax ¼ 88.6 þ 2.00 Mv; He ¼ 85.4 þ 1.74 Mv (N ¼ 14) Ib: r  0.57  0.43 g/cm3 (a1 ¼ 0.058 km, a2 ¼ 6.29/s), lower if fragile III: Possibly Na poor/free From c: and s: w65,000 y C/1760 B1 (Messier) duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.801 (1.000) 79.1 273.9 143.0 56.9

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1759-Nov-27.5 TDB

Brief history: First identified by [1] from 16 meteors in 8 days with R.A. ¼ 63.3 , Decl. ¼ þ72.9 and Vg ¼ 50.8  1.5 km/s around lo ¼ 191 (range lo ¼ 189e196 ), noticing steep inclination of the orbit. Confirmed by [2], but not with exact same range of orbits, rather concentrated near lowest R.A. in range. Name and number by [1]. References: [1] Andreic Z., et al. (2014) JIMO 42, 90e97. [2] Jenniskens P., et al. (2016) Icarus 266, 355e370. October 2 (lo ¼ 190 )

715 ACL d alpha Camelopardalids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy: Age: Source:

Long-period comet, TJ ¼ þ0.11  0.43 Annual shower e September 28eOctober 10 (lo ¼ 185 e198 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 190.1 87.1 þ65.6 258.2 þ42.3 57.1 þ2.35 0.09 þ0.31 0.09 þ0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.8 0.949 0.919 106.9 207.1 190.1 36.9 0.0112 0.097 2.07 3.43 3.28 3.43 þ0.0018 þ0.0006 þ0.23 0.59 þ1.00 þ0.41 w0.3/h (N ¼ 196, hr ¼ 46.7 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.70  0.35 (s ¼ 2.42  0.10) Ib: Hb ¼ 110.5  0.69 Mv; Hmax ¼ 102.1 þ 1.32 Mv; He ¼ 97.3 þ 1.45 Mv (N ¼ 108) Ib: r w 0.57 g/cm3 (a1 ¼ 0.068 km, a2 ¼ 6.16/s) Ia: Na0.084 (N ¼ 1), Na enhanced; AMOS: Mg1.00 Fe0.96 Na0.119 (N ¼ 1) [2] From c and s: w84,000 y e

eV

Brief history: First detected by [1] at R.A. ¼ 77.1 , Decl. ¼ þ64.8 with Vg ¼ 59.8 km/s around lo ¼ 183 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409; [2] Matlovic P., et al. (2019) AA 629, A71eA90.

326

Northern apex

23 EGEdepsilon Geminids

October

327

October 10 (lo ¼ 197 )

880 YDR d Y Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.31  0.42 Annual shower October 7e14 (lo ¼ 194 e201 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 196.9 100.5 þ77.8 257.5 þ55.6 50.2 þ2.66 0.31 þ0.06 0.21 þ0.16 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.8 0.972 0.946 88.0 199.4 196.9 36.5 eV 0.0058 0.076 1.23 2.18 1.97 2.18 0.0004 þ0.0013 þ0.33 þ0.04 þ1.00 þ1.04 w0.2/h (N ¼ 57, hr ¼ 44.8 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.86  0.16 (s ¼ 2.14  0.07) I: Hb ¼ 110.4  1.81 Mv; Hmax ¼ 100.3 þ 0.77 Mv; He ¼ 95.2 þ 1.44 Mv (N ¼ 37) I: r w 0.38 g/cm3 (a1 ¼ 0.198 km, a2 ¼ 4.28/s) duncertain due to low N From c and s: w50,000 y; high dP/dlo versus i e

Brief history: Perhaps first detected by [1] based on 16 CAMS-triangulated meteors from R.A. ¼ 146.4 , Decl. ¼ þ76.4 with Vg ¼ 47.6 km/s around lo ¼ 206.3 , just outside the interval extracted here. Distinct from #383: [2] detected a more extended shower toward higher l with slower meteors (called 383 LDRdlambda Draconids) from R.A. ¼ 156.1 , Decl. ¼ þ74.7 and Vg ¼ 37.5 km/s around lo ¼ 196 , along the toroidal source. MAARSY data show a hint of that activity, but not well enough defined to confirm the shower here. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29; [2] Brown P., et al. (2010) Icarus 207, 66e81. October 23 (lo ¼ 209 )

645 PHC d phi Cancrids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.07  0.41 Annual shower e September 12eNovember 8 (lo ¼ 169 e226 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 208.6 138.8 þ29.6 284.0 þ12.6 67.2 þ1.09 0.15 þ0.20 0.30 0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.07 0.837 0.841 156.4 130.2 208.6 339.2 eV 0.031 0.120 4.16 5.80 12.1 5.80 þ0.0070 0.0016 0.16 þ0.80 þ1.00 þ1.80 w0.8/h (N ¼ 1673, hr ¼ 45.0 , m(Mv ¼ 0) ¼ 0.02 g) c ¼ 3.12  0.09 (s ¼ 2.23  0.03) Component IIb has low He, Ke < 79, like III: I: Hb ¼ 113.5  1.41 Mv; Hmax ¼ 103.7 þ 1.21 Mv; He ¼ 98.8 þ 1.80 Mv (N ¼ 871) III: Hb ¼ 99.3  0.57 Mv; Hmax ¼ 94.9 þ 0.69 Mv; He ¼ 90.0 þ 1.35 Mv (N ¼ 30) I: r w 0.51  0.31 g/cm3 (a1 ¼ 0.063 km, a2 ¼ 6.88/s) III: r w 2.2 g/cm3 (a1 ¼ 0.025 km, a2 ¼ 18.22/s) dpossibly Na poor From c and s: w76,000 y e

Meteoroid density: Age: Source:

Brief history: Strong change of P with solar longitude, peak activity toward end of activity range. First described by [1] from 10 CAMS-detected meteors at R.A. ¼ 121.1 , Decl. ¼ þ29.3 with Vg ¼ 67.8 km/s around lo ¼ 190.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

328

Northern apex

October

October 5 (lo ¼ 192.5 )

281 OCT d October Camelopardalids

Dynamic type: Shower type: Years of outbursts:

Long-period comet, TJ ¼ þ0.50  0.33 Annual shower with episodic outbursts (1902, 1942, 1976) 2005, 2016: lo ¼ 192.56 , ZHR ¼ 44/h [12]; 2017: lo ¼ 192.50 , 11/h; 30  8/h [10]; 2018: lo ¼ 192.45 , ZHR ¼ 5/h [11] October 5e6 (lo ¼ 192.0 e192.9 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 192.53 169.1 þ78.6 281.9 þ62.2 45.9 þ0.51 0.48 þ0.02 0.17 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 23.9 0.991 0.958 77.7 169.1 192.5 1.6 0.0024 0.122 1.47 1.55 0.14 1.55 0.0002 0.0295 þ0.02 0.06 þ1.00 þ0.94 N ¼ 255 (hr ¼ 29.9 , m(Mv ¼ 0) ¼ 0.05 g) Annual: w3/h [9]; ZHR ¼ 5/h [6], variable 0%e12% of sporadics [7]; 4  1/h [10] 2011e2016: Peak on lo ¼ 192.59 with flux density ¼ 0.007 km2 h1 [9] c ¼ 1.70  0.10 (s ¼ 1.58  0.07); s ¼ 1.4  0.2 [4]; c ¼ 1.95 [9]; c ¼ 1.75 [10] Component I has high He: I: Hb ¼ 109.6  0.83 Mv; Hmax ¼ 102.3 þ 0.74 Mv; He ¼ 95.7 þ 1.50 Mv (N ¼ 132) I: low F ¼ 0.53, fragile meteoroids I: r w 0.43  0.11 g/cm3 (a1 ¼ 0.121 km, a2 ¼ 3.53/s) From c and s: 8,000 y; Earth passing through core of stream (sU < su) e

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

329

eV

Brief history: Short-duration shower (Fig. 6.10), first recognized during an outburst in 2005. Occasional showers of bright meteors on October 4/5 were known for some time before that [1]. In 1902, [2] reported seeing 50 light tracks behind clouds from Stonyhurst College, Blackburn, UK in the evening between 19:45 and 20:00 UT (lo ¼ 192.009 ). In 1942, [3] reported a significant meteor shower in the evening of October 5 (lo ¼ 192.7  0.1 ) radiating from Cassiopeia, typically þ3 magnitude and yellow in color. In 1976, [4] from Pompano Beach, Florida, saw 113 meteors moving from N to E between 02:55 and 04:37 UT October 6 (lo ¼ 193.31e193.38 ). On October 5, 2005, J. Moilanen (Finland) recorded 12 meteors in low-light video FIG 6.10 ZHR profile. observations from R.A. ¼ 164.1  2.0 and  Decl. ¼ þ78.9  0.5 centered on lo ¼ 192.57 [5], providing the first orbital elements. In 2007e2016 activity accounted for a variable 0%e12% of all activity on that date in CAMS low-light video observations, with #281 about 0.3 magnitude brighter on average than all other meteors [7]. Photographed 5 magnitude meteor by [8] has a >41 (nominally 270) AU. Model by [5,12] predicted returns in 2017 [13] and 2018. Name by [5], number by [1]. References: [1] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp.; [2] Bailey G. P. (1902) Nature 66, 577e577; [3] Sandner W. (1943) Sterne 23, 46e46; [4] Root E. (1976) Meteor News 36, 13; [5] Jenniskens P., Moilanen J., Lyytinen E., Yrjola I., Brower J. (2005) JIMO 33, 125e128, and 33, 145e145; [6] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [7] Roggemans P., Johannink C., Cambell-Burns P. (2019) eMeteorNews 4, 65e73; [8] Borovicka J., Spurny P. (2006) JIMO 34, 85e86; [9] Molau S., et al. (2019) JIMO 47, 188e190; [10] Molau S., et al. (2018) JIMO 46, 136e141; [11] Rendtel J. (2018) JIMO 46, 173e175; [12] Lyytinen E. (2016) eMeteorNews 1, 135e136 [13] Johannink C. (2018) eMeteorNews 3, 19e20.

330

Northern apex

October

October 8 (lo ¼ 195 )

848 OPE d omicron Perseids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, sunskirter, TJ ¼ þ0.17  0.40 Annual shower e September 24eOctober 20 (lo ¼ 193 e196 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 194.6 50.3 þ30.5 221.0 þ11.6 53.5 þ0.91 þ0.45 0.11 þ0.23 þ0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 19.2 0.076 0.996 113.7 328.5 194.6 163.1 0.0099 0.006 3.32 2.35 0.36 2.35 þ0.0030 þ0.0019 0.84 0.66 þ1.00 þ0.33 w0.06/h (N ¼ 19, hr ¼ 63.9 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 1.94  0.07 (s ¼ 1.72  0.04) Ib: Hb ¼ 108.5  1.30 Mv; Hmax ¼ 100.0  0.04 Mv; He ¼ 96.0 þ 0.59 Mv (N ¼ 13) Ib: r w 0.98 g/cm3 (a1 ¼ 0.035 km, a2 ¼ 9.70/s) From c: 500 y, from s: w3700 y; Earth through core stream (sU < su) e

331

eV

Brief history: Low-q shower, first detected from 11 meteors by [1] at R.A. ¼ 53.5 , Decl. ¼ þ31.5 with Vg ¼ 51.7 km/s around lo ¼ 198.1 . Possibly weaker shower just below it. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29. October 13 (lo ¼ 200 )

1149 OXP d October xi Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, sunskirter, TJ ¼ þ0.45  0.33 Annual shower October 9e16 (lo ¼ 196 e203 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 200.0 57.7 þ36.4 223.5 þ15.9 53.4 þ1.04 þ0.25 0.09 þ0.05 0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.29 0.136 0.983 110.2 317.7 200.0 156.8 eV 0.0134 0.0143 3.52 3.33 2.29 3.33 0.0008 0.0007 0.61 þ0.19 þ1.00 þ1.19 0.04/h (N ¼ 40, hr ¼ 60.0 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.99  0.52 (s ¼ 2.19  0.20) III: Hb ¼ 95.8 þ 0.55 Mv; Hmax ¼ 90.3 þ 1.39 Mv; He ¼ 85.4 þ 1.40 Mv (N ¼ 26) III: r w 4.6  1.4 g/cm3 (a1 ¼ 0.016 km, a2 ¼ 15.64/s) dpossibly Na poor (low N) From c and s: w9300 y; high dP/dlo versus i e

Brief history: Deeply penetrating meteoroids. First detected here.

332

Northern apex

333

October

October 12 (lo ¼ 220 )

847 BEL d beta Leonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ 0.23  0.38 Annual shower October 7e18 (lo ¼ 215 e226 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 220.1 180.8 þ17.2 313.9 þ0.72 0.39 0.18 a (AU) q (AU) e i ( ) 72.4 0.194 0.998 122.1 0.0158 0.0130 1.76 þ0.0024 þ0.0015 þ0.70 w0.4/h (N ¼ 41, hr ¼ 25.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 3.24  0.29 (s ¼ 2.28  0.10) I: Hb ¼ 111.6  1.11 Mv; Hmax ¼ 101.2 þ 1.34 Mv; I: r w 1.2 g/cm3 (a1 ¼ 0.018 km, a2 ¼ 6.14/s) From c and s: w13,000 y; high dP/dlo versus i e

b ( ) þ15.9 0.07 u ( ) 52.4 2.87 þ0.43

Vg (km/s) 57.6 þ0.19 U ( ) 220.1 2.26 þ1.00

P ( ) 271.4 2.87 þ1.43

eV

He ¼ 96.4 þ 2.01 Mv (N ¼ 26) duncertain due to low N

Brief history: Compact radiant. First reported by [1] with R.A. ¼ 179.4 , Decl. ¼ þ17.3 and Vg ¼ 57.4 km/s around lo ¼ 218.8 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29. October 5 (lo ¼ 192 )

1150 GAC d October gamma Cepheids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ1.01  0.84 Annual shower More detections in 2015/16 and 2021 October 2e8 (lo ¼ 189 e195 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 192.2 353.9 þ80.7 234.8 þ65.8 39.8 þ1.41 þ0.35 0.06 0.12 0.38 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.64 0.939 0.902 65.8 208.8 192.2 41.4 eV 0.0070 0.148 2.35 2.78 0.55 2.78 0.0037 0.0097 1.53 þ1.84 þ1.00 þ2.84 w0.1/h (N ¼ 41, hr ¼ 42.6 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 1.84  0.07 (s ¼ 1.66  0.04) I: Hb ¼ 106.5  1.67 Mv; Hmax ¼ 95.8 þ 1.19 Mv; He ¼ 89.3 þ 2.94 Mv (N ¼ 16) duncertain due to low N I: r w 0.32  0.14 g/cm3 (a1 ¼ 0.076 km, a2 ¼ 5.55/s) From c and s: 10,000 y; Earth passing through core of stream (sU < su) e

Brief history: First detected here. Short duration of shower suggests that there may be occasional meteor outbursts. Number of detections starting in 2011: 1, 0, 1, 2, 5, 6, 2, 3, 3, 1, 18.

334

Northern apex

October

October 14 (lo ¼ 201 )

745 OSD d October 6 Draconids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, TJ ¼ þ0.51  0.44 Annual shower 2011/2012, 2016/2017, and 2020/2021 September 27eOctober 17 (lo ¼ 200.6 e202.1 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 201.2 187.0 þ68.4 296.5 þ60.6 45.2 þ2.44 0.38 þ0.67 þ0.49 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 25.7 0.945 0.963 75.7 153.4 201.2 354.5 0.0042 0.077 1.14 1.50 0.40 1.50 0.0018 0.0522 1.63 0.91 þ1.00 þ0.09 w0.2/h (N ¼ 38, hr ¼ 28.0 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 1.81  0.12 (s ¼ 1.65  0.07) Component I has high He: Ib: Hb ¼ 107.0  0.93 Mv; Hmax ¼ 99.7 þ 0.76 Mv; He ¼ 94.7 þ 0.45 Mv (N ¼ 21) Ib: low F ¼ 0.59, normal KE, borderline fragile Ib: r  0.55 g/cm3 (a1 ¼ 0.134 km, a2 ¼ 3.90/s), smaller if fragile From s: 11,000 y; from c younger Earth passing through core of stream (sU < su) e

Lightcurve shape: Meteoroid density: Age: Source:

335

eV

Brief history: First detected by [1] with R.A. ¼ 181.9 , Decl. ¼ þ71.4 and Vg ¼ 42.7 km/s around lo ¼ 189.9 . Compact shower of short duration (hence drift with solar longitude values uncertain), but some meteors detected annually. Number of orbits measured per year with increasing number of cameras, starting in 2007: 0, 2, 0, 0, 5, 5, 3, 3, 0, 3, 5, 2, 2, 10, 18, and 6. Higher counts in 2011/2012, 2016/2017, and 2020/2021 suggests a ~4.5-year period and that meteoroids are trapped in the 5:2 mean-motion resonance. with Jupiter. Activity curve from combined count shown in Fig. 6.11. Name and number by [1]. FIG 6.11

ZHR profile, scale uncertain.

References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

336

Northern apex

October

337

October 16 (lo ¼ 202 ) 333 OCU d October Ursae Majorids Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Lightcurve shape: Meteoroid density:

Spectroscopy: Age:

Long-period comet, TJ ¼ þ0.12  0.40 Annual shower, possibly weak variability 2013: lo ¼ 202.09  0.018 , W ¼ 0.16 , N ¼ 14 2017: lo ¼ 201.65  0.014 , W ¼ 0.20 , N ¼ 37 October 9e24 (lo ¼ 195 e210 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 202.4 145.4 þ64.1 279.1 þ46.5 55.5 þ1.82 0.62 þ0.47 0.16 þ0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.2 0.979 0.936 100.9 164.1 202.4 6.6 eV 0.0076 0.124 2.59 3.26 1.76 3.26 0.0028 þ0.0003 þ0.13 0.98 þ1.00 þ0.02 N ¼ 935 (hr ¼ 35.6 , m(Mv ¼ 0) ¼ 0.03 g) Annual: w1.4/h; ZHR 134 , when the rate has dropped to low values. This August component has a slightly displaced radiant as discussed by [1]. Graph shows lo ¼ 135 e145 as thick black points (#692) and lo ¼ 125 e135 a thin gray points (#1) for TJ < 3. Median values in table are for all TJ. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354.

574

Anthelion source

August

575

August 14 (lo ¼ 141 )

3 SIA d Southern iota Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, TJ ¼ þ3.68  0.42 Annual shower July 11eSeptember 6 (lo ¼ 109 e163 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 141.1 342.3 11.3 199.2 3.6 30.0 þ0.86 þ0.32 0.10 0.01 0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.60 0.244 0.853 5.16 131.2 321.1 89.9 eV 0.0415 0.041 1.83 4.94 13.56 4.94 þ0.0021 0.0013 0.01 0.23 þ1.00 þ0.76 1.55 0.218 0.859 5.3 134.3 309.1 83.4 e R[8] w0.2/h (N ¼ 989, hr ¼ 43.7 , m(Mv ¼ 0) ¼ 0.15 g) c ¼ 2.82  0.14 (s ¼ 2.13  0.05) No clear separation between IIa and IIb: IIa: Hb ¼ 99.3  1.04 Mv; Hmax ¼ 87.4 þ 0.92 Mv; He ¼ 80.8 þ 1.79 Mv (N ¼ 390) IIb: Hb ¼ 90.5  0.54 Mv; Hmax ¼ 86.1 þ 0.07 Mv; He ¼ 81.8 þ 0.43 Mv (N ¼ 311) IIa: r w 1.8  0.6 g/cm3 (a1 ¼ 0.070 km, a2 ¼ 3.84/s) dNa poor IIb: r w 2.6  0.9 g/cm3 (a1 ¼ 0.050 km, a2 ¼ 8.10/s) dNa free Mg1.49 Fe1.09 Na0.023 (N ¼ 2), low O, Na depleted e e

Meteoroid density: Spectroscopy: Age: Source:

Brief history: Shower is at the center of the sporadic anthelion source. Not part of the Southern Taurids (#2) based on velocity versus solar longitude plot (Fig. 8.9). First reported by [1] from 6 photographed orbits with a mean radiant at R.A. ¼ 337.8 , Decl. ¼ 14.1 and Vg ¼ 32.2  2.8 km/s on lo ¼ 135.3 , over period 97.6e149.0 (B1950.0). The semi-major axis of the orbits ranged from a ¼ 1.285 to a ¼ 3.337 AU and P ¼ 51.8e104.2 . Again found in photographic orbit surveys by [2e4], but with significantly different radiant positions (e.g., inclinations in range 0 e9 ) [5]. [10] had median l ¼ 198.3, b ¼ 1.7 and Vg ¼ 34.9 km/s around lo ¼ 129.9 [9]. Not detected in early video data by [7]. Subsequently removed from “established” status in 2012. Confirmed by [9]. More clearly detected in radar data. [2] pointed to possible earlier Adelaide radar envelope-contour detection. First radar orbit detection by [6] (their shower 27). Confirmed by [8] as short-period orbits with R.A. ¼ 332.9 , Decl. ¼ 14.7 and Vg ¼ 30.5 km/s on lo ¼ 129.5 . With more data in hand, now detected in video data also, but only among TJ > 3 orbits. Name by [1] and number by [2,3]. References: [1] Wright F. W., Jacchia L. G., Whipple F. L. (1957) AJ 62, 225e233; [2] Jacchia L. G. (1963) In: The Moon, Meteorites and Comets. Eds.: B. M. Middlehurst, G. P. Kuiper, Chicago: University of Chicago Press, p. 774e798; [3] Southworth R. B., Hawkins G. S. (1963) SCoA 7, 261e285; [4] Lindblad B. A. (1971) SCoA 12, 14e24; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 720; [6] Kashcheyev B. L., Lebedinets V. N. (1963) SCoA 7, 183e199; [7] Holman D., Jenniskens P. (2012) JIMO 40, 166e170; [8] Brown P., et al. (2008) Icarus 195, 317e339; [9] Koseki M. (2019) JIMO 47, 139e150; [10] McCrosky R. E., Posen A. (1961) SCoA 4, 15e84.

FIG 8.9 Finding chart of #3 versus N. and S. Taurids.

576

Anthelion source

August

577

August 9 (lo ¼ 136 )

640 AOA d August omicron Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, Machholz Complex, TJ ¼ þ2.65  0.45 Annual shower August 4e31 (lo ¼ 132 e167 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 136.1 349.4 14.3 206.6 8.5 38.6 þ0.77 þ0.24 0.20 0.08 0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.37 0.109 0.954 24.9 145.2 316.1 103.2 eV 0.0304 0.0391 6.93 4.03 7.58 4.03 þ0.0033 0.0014 0.21 0.51 þ1.00 þ0.49 w6/h (N ¼ 9810, hr ¼ 42.1 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 3.61  0.05 (s ¼ 2.39  0.01) II: Hb ¼ 97.9  0.70 Mv; Hmax ¼ 90.7 þ 0.73 Mv; He ¼ 85.8 þ 1.06 Mv (N ¼ 7027) r ¼ 2.65  0.50 and 3.15  0.60 g/cm3 (N ¼ 2) [2] dNa poor/free II: r w 1.20  0.11 g/cm3 (a1 ¼ 0.086 km, a2 ¼ 5.96/s) Mg0.57 Fe1.10 Na0.011 (N ¼ 2), Na depleted From c: 15,000 y 96P/Machholz a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.03 0.124 0.959 58.5 14.7 94.4 109.1

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2008-Nov-03.0 TDB

Brief history: Part of Machholz complex, consisting of late members of shower #5. [1] recognized that late Southern delta Aquariids (#5) after lo ¼ 132 have less intrinsic radiant drift and a lower semi-major axis. Activity curve shown in Fig. 8.10. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] J.-B. Kikwaya Eluo (2011) Bulk density of small meteoroids. PhD Thesis, London: University of Western Ontario, p. 235.

FIG 8.10

ZHR profile.

578

Anthelion source

August

579

August 16 (lo ¼ 144 )

199 ADC d August delta Capricornids

Dynamic type: Shower type: Years of outbursts:

Jupiter-family comet, TJ ¼ þ2.58  0.50 Episodic shower 2022: lo ¼ 143.16  0.02 , W ¼ 0.25 (N ¼ 33) 2022: lo ¼ 143.707  0.008 , W ¼ 0.19 , W ¼ (N ¼ 98)d1980-dust trail [7] August 14e17 (lo ¼ 142 e145 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 143.7 325.2 11.4 180.0 þ2.3 24.1 þ1.33 þ0.98 þ0.55 þ0.50 0.20 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.06 0.548 0.821 1.96 270.9 143.7 54.5 eV 0.0168 0.0544 0.80 1.65 0.40 1.65 0.0051 0.0183 0.04 þ0.79 þ1.00 þ1.21 N ¼ 137 (hr ¼ 55.6 , m(Mv ¼ 0) ¼ 0.25 g) w10 [9] c ¼ 2.20  0.15 (s ¼ 1.86  0.08)dperhaps cut-off at þ3 magn. Ib: Hb ¼ 99.0  1.51 Mv; Hmax ¼ 87.0 þ 0.85 Mv; He ¼ 80.8 þ 1.38 Mv (N ¼ 124) IIIb: Hb ¼ 83.7 þ 0.42 Mv; Hmax ¼ 78.9 þ 1.32 Mv; He ¼ 74.2 þ 2.34 Mv (N ¼ 9) Ib: r w 1.3  0.7 g/cm3 (a1 ¼ 0.360 km, a2 ¼ 1.47/s) dpossibly Na poor/free IIIb: r w 4.7 g/cm3 (a1 ¼ 0.015 km, a2 ¼ 7.71/s) Line strength: Na/Mg ¼ 1.31 [9], or roughly Na0.054 dchondritic 2022: 42 y 45P/Honda-Mrkos-Pajdusáková a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.03 0.533 0.824 4.25 326.3 88.9 55.2

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2017-Aug-14.0 TDB

Brief history: Shower first detected by [1] (shower 43) in a D-criterion search for fireball streams, with meteors radiating from R.A. ¼ 324.7 , Decl. ¼ 13.8 (B1950) and Vg ¼ 22.0 km/s during August 13e31, named “dCapricornids.” Confirmed by [2] in a Dcriterion search among 1000 photographed orbits of meteors brighter than 3. Up to that point, the shower identification remained uncertain. Detected as an outburst from lowlight CAMS video observations on August 16, 2022 [3,4], found to have consisted of two dust trail crossings. Main outburst confirmed from SonotaCo data by [5]. Secondary peak also detected by GMN during 143.05 e143.32 by [9]. Source 45P identified by [5]. The difference in orientation of the nodal line of the current orbit is mostly a consequence of a close encounter of the comet with Jupiter in 1983. Dust trail model by S. Shanov and S. Dubrovski in [6] put the 1969 dust of 45P in Earth’s path on August 14, 2015, at lo ¼ 140.990 radiating from R.A. ¼ 325.8 , Decl. ¼ 10.7 with Vg ¼ 25.63 km/s, but that event was not observed. [7] named the shower “s-Capricornids” and predicted an encounter with the 1980-dust ejected by 45P on August 16, 2022 at 23:40 UT, passing Earth at 0.00377 AU and requiring an ejection speed of 9.82 m/s. Predicted radiant given as R.A. ¼ 326.8 , Decl. ¼ 15.1 . The observed radiant during the second peak was R.A. ¼ 325.28  0.06, Decl. ¼ 11.40  0.06, and Vg ¼ 24.12  0.14 km/s. [9] gives spectral information. [8] calculated dust trail encounters with Venus in 2006. Was initially given the designation M2022-Q1 by the Meteor Data Center, the first example following the introduction of shower designations by the IAU Commission F1 in 2022. Name by [1], number by [6]. References: [1] Terentjeva A. K., (1989) JIMO 17, 242e245; [2] Porubcan V., Gavajdova M. (1994) PSS 42, 151e155; [3] Jenniskens P. (2022) 18-Aquariids meteor shower 2022. CBET 5159. Ed.: D. W. E. Green, Cambridge: CBAT, p. 1e1; [4] Jenniskens P. (2022) eMeteorNews 7, 304e305 and 306e306; [5] Sekiguchi T. (2022) eMeteorNews 7, 302e304; [6] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: Cambridge University Press, p. 683; [7] Maslov M. (2014) http://feraj.ru/Radiants/Predictions/45p-ids2022eng.html (last accessed August 19, 2022); [8] Vaubaillon J., Christou A. A. (2006) AA 451, L5eL8; [9] Roggemans P., Segon D., Vida D., Greaves J., Sekiguchi T., Angelsky A., Davydov A. (2022) eMeteorNews 7, 293e301.

580

Anthelion source

26 NDAdNorthern delta Aquariids

581

August

August 18 (lo ¼ 145 )

26 NDA d Northern delta Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, Machholz Complex, TJ ¼ þ2.70  0.49 Annual shower July 24eSeptember 22 (lo ¼ 122 e180 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 145.4 351.6 þ4.1 207.4 þ7.0 38.4 þ0.79 þ0.34 þ0.00 0.15 0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.18 0.098 0.955 21.4 328.5 145.4 114.2 0.0230 0.028 7.23 4.18 11.47 4.18 þ0.0019 0.0010 0.22 0.31 þ1.00 þ0.69 w2/h (N ¼ 9033, hr ¼ 48.2 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 3.22  0.12 (s ¼ 2.26  0.04) II: Hb ¼ 96.7  0.49 Mv; Hmax ¼ 89.9 þ 0.85 Mv; He ¼ 85.2 þ 1.15 Mv (N ¼ 5742) r ¼ 2.2 g/cm3 [10] II: r w 1.25  0.21 g/cm3 (a1 ¼ 0.091 km, a2 ¼ 6.05/s) Mg1.01 Fe0.56 Na0.021 (N ¼ 3), Na poor 10,000e20,000 y [8]; from c: 12,000 y 96P/Machholz a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.03 0.124 0.959 58.5 14.7 94.4 109.1

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2008-Nov-03.0 TDB

eV

Brief history: This shower of the Machholz Complex has been long confused by visual observers with the nearby shower #164 of the June Aquilid Complex. Early radar detection by [13] (shower 61.8.6) from R.A. ¼ 352.7 , Decl. ¼ þ6.3 , and Vg ¼ 36.0 km/s around lo ¼ 148.3 (B1950.0). First photographic orbits were calculated by [1] from R.A. ¼ 338.9 , Decl. ¼ 0.7 and Vg ¼ 27.3e41.3 km/s around lo ¼ 132.5 (B1950.0), who named the shower “Northern delta Aquarids.” Using a new D criterion, [7] detected 8 NDA between August 5 and 25 among photographed orbits. Radar detection by [4]. First detection in video data by [5]. Confirmation by [6], making distinction between Northern delta Aquariids (#26) and Northern June Aquilids (#164). Activity curve in Fig. 8.11. #26 was called “342 BPI e beta Piscids” by [12]. Models by [2,3]. [9] called “Filament 2” in model of 96P ejecta; [8] proposed shower activity was from 96P/Machholz itself. Name by [1], number by [11].

FIG 8.11

ZHR profile.

References: [1] Wright F. W., Jacchia L. G., Whipple F. L. (1957) Astron. J. 62, 225e233; [2] Neslusan L., Hajduková M., Jakubík M. (2013) AA 560, 47e56; [3] Neslusan L., Kanuchová Z., Tomko D. (2013) AA 551, 87e101 [4] Sekanina Z. (1970) Icarus 13, 475e493; [5] de Lignie M., Jobse K. (1997) JIMO 25, 130e135; [6] Holman D., Jenniskens P. (2012) JIMO 40, 166e170; [7] Jopek T. J., Valsecchi G. B., Froeschle Cl. (1999) MNRAS 304, 751e758; [8] Abedin A., et al. (2018) Icarus 300, 360e385; [9] Neslusan L., Hajduková M., Jakubík M. (2015) AA 560, A47eA57; [10] Babadzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [11] McCrosky R.E., Posen A. (1961) SCoA 4, 15e84; [12] Kanamori T. (2009) JIMO 37, 55e62; [13] Nilsson C. S. (1964) AuJPh 17, 205e256.

582

Anthelion source

August

583

August 24 (lo ¼ 152 )

505 IAC d August iota Cetids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, Machholz Complex, TJ ¼ þ2.69  0.45 Annual shower August 4eSeptember 22 (lo ¼ 132 e180 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 151.8 1.4 6.8 207.0 6.6 38.5 þ0.79 þ0.29 0.16 0.05 0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.23 0.097 0.957 20.0 148.2 331.8 119.4 eV 0.0222 0.025 5.25 3.46 12.3 3.46 þ0.0026 0.0011 0.13 0.40 þ1.00 þ0.60 w1/h (N ¼ 3633, hr ¼ 44.6 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 3.41  0.07 (s ¼ 2.33  0.02) II: Hb ¼ 97.0  0.52 Mv; Hmax ¼ 90.1 þ 0.76 Mv; He ¼ 85.3 þ 1.10 Mv (N ¼ 2447) IV: Hb ¼ 82.8  0.86 Mv; Hmax ¼ 72.6 þ 0.87 Mv; He ¼ 63.7 þ 0.53 Mv (N ¼ 7) r ¼ 2.78  0.60 g/cm3 [4] II: r w 1.19  0.23 g/cm3 (a1 ¼ 0.0965 km, a2 ¼ 5.87/s) dNa poor Mg0.88 Fe0.58 Na0.016 (N ¼ 2), Na depleted From c: 12,000 y 96P/Machholz 1 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.03 0.123 0.959 58.5 14.7 94.4 109.1

Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2008-Nov-03.0 TDB

Brief history: First recognized by [1] from 13 video-derived orbits from the 2007e2010 Croatian Meteor Network and 10 from the 2007e2009 SonotaCo database during the Visnjan School of Astronomy in 2012. Meteors radiated from R.A. ¼ 0.4 , Decl. ¼ 6.4 with Vg ¼ 37.9 km/s around lo ¼ 142.2 , from a radiant separate from that of the nearby #5/ 640 in August and September. Found again by [2] from R.A. ¼ 356.8 , Decl. ¼ 9.6 with Vg ¼ 37.2 km/s on lo ¼ 145.4 , with a mean daily motion of þ0.71 in RA and þ0.21 in Decl. during lo ¼ 128e164 . Grouped to Machholz complex by [3]. Name and number by [2]. References: [1] Vida D., et al. (2012) In: IMC 2012, Ed.: M. Gyssens, P. Roggemans, Mechelen: IMO, p. 1e3; [2] Andreic Z., et al. (2014) JIMO 41, 40e42; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Kikwaya Eluo J.-B. (2011) Bulk density of small meteoroids. PhD Thesis, London: University of Western Ontario, p. 234. August 25 (lo ¼ 152 )

1085 NCQ d Northern chi Aquariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Jupiter-family comet, sunskirter, TJ ¼ þ2.53  0.39 Annual shower August 24e31 (lo ¼ 135 e176 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 152.2 357.4 þ4.3 207.0 þ4.8 39.2 þ0.72 þ0.33 0.21 þ0.02 0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.39 0.087 0.964 15.5 329.7 152.2 121.5 0.0137 0.0148 2.83 2.30 9.91 2.30 þ0.0028 0.0011 0.23 0.51 þ1.00 þ0.49 w0.1/h (N ¼ 589, hr ¼ 48.1 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.74  0.06 (s ¼ 2.09  0.03) II: Hb ¼ 97.2  0.50 Mv; Hmax ¼ 90.2 þ 0.91 Mv; He ¼ 85.3 þ 1.30 Mv (N ¼ 362) II: r w 1.4  0.4 g/cm3 (a1 ¼ 0.080 km, a2 ¼ 6.57/s) From c: 9000 y 96P/Machholz 1

eV

Brief history: First reported here. Northern counterpart to shower #505. Part of Machholz Complex.

584

Anthelion source

33 NIAdNorthern iota Aquariids

September

585

September 17 (lo ¼ 175 ) 33 NIA d Northern iota Aquariids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

Jupiter-family comet or asteroid, TJ ¼ þ3.68  0.39 Annual shower July 30eNovember 30 (lo ¼ 126 e248 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 174.8 7.5 þ7.5 194.5 þ3.9 26.9 þ0.74 þ0.29 0.21 0.00 0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.71 0.321 0.800 4.6 302.1 174.8 116.4 eV 0.0527 0.061 1.97 6.38 22.1 6.38 þ0.0040 0.0020 0.04 0.47 þ1.00 þ0.53 w1/h (N ¼ 6984, hr ¼ 49.5 , m(Mv ¼ 0) ¼ 0.20 g) c ¼ 3.73  0.40 (s ¼ 2.43  0.11) Ib: Hb ¼ 99.4  1.02 Mv; Hmax ¼ 86.3 þ 1.17 Mv; He ¼ 80.4 þ 1.75 Mv (N ¼ 2655) II: Hb ¼ 93.7  0.90 Mv; Hmax ¼ 85.8 þ 0.52 Mv; He ¼ 81.0 þ 1.02 Mv (N ¼ 1154) III: Hb ¼ 87.3  0.58 Mv; Hmax ¼ 84.0 þ 0.18 Mv; He ¼ 79.8 þ 0.51 Mv (N ¼ 771) r ¼ 2.86  1.00 g/cm3 (N ¼ 1) [10] Ib: r w 1.7  0.3 g/cm3 (a1 ¼ 0.065 km, a2 ¼ 3.59/s) dNa chondritic II: r w 2.2  0.8 g/cm3 (a1 ¼ 0.048 km, a2 ¼ 4.97/s) dNa free dpossibly Na free III: r w 3.1  0.6 g/cm3 (a1 ¼ 0.050 km, a2 ¼ 7.27/s) Mg0.95 Fe0.61 Na0.025 (N ¼ 2); AMOS: Mg1.00 Fe0.53 Na0.002 (N ¼ 1) [12] e 2015 QT3 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.16 0.432 0.800 5.06 288.9 153.2 82.1

Brief history: Not part of Northern Taurids (#17) based on change of velocity with solar longitude (see Fig. 8.12). First identified from photographic orbits by [1] from R.A. ¼ 348.9 , Decl. ¼ 1.6 with speed Vg ¼ 29.5 km/s over lo ¼ 145e159 . Radar detections by Adelaide radar [2] (Shower 61.8.2), from R.A. ¼ 352.1 , Decl. ¼ 1.0 with Vg ¼ 28.2 km/s during August 13e28. [3] detected a radar shower from 42 meteor orbits measured during 1961e1965 in the Harvard Radio Meteor Project, with R.A. ¼ þ0.8 , Decl. ¼ þ3.9 centered on lo ¼ 168.3 , and called it the “Piscids” (Table I, p. 257). [4] confirmed the detection from 1968e1969 data (Table VI, p. 285), now placing the radiant at R.A. ¼ 9.1 , Decl. ¼ þ7.2 and Vg ¼ 25.6 km/s on lo ¼ 173.5 . Also detected by CMOR [5] from R.A. ¼ 356.0 , Decl. ¼ þ3.0 with Vg ¼ 28.6 km/s, in good agreement with video data [8]. Detected in photographed orbit surveys with small numbers during solar longitudes of 138 e162 [6,7]. Association with 2015 QT3 by [9], statistically significant. Name by [1], number by [11]. References: [1] Wright F. W., Jacchia L. G., Whipple F. L. (1957) AJ 62, 225e233; [2] Nilsson C. S. (1964) AuJPh 17, 205e256; [3] Sekanina Z. (1973) Icarus 18, 253e284; [4] Sekanina Z (1976) Icarus 27, 265e321; [5] Brown P., et al. (2008) Icarus 195, 317e339; [6] Lindblad B. A. (1971) SCoA 12, 14e24; [7] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [8] Jenniskens P., et al. (2016) Icarus 266, 331e354; [9] Guennoun M., et al. (2019) AA 622, A84eA93; [10] Kikwaya Eluo J.-B. (2011) Bulk density of small meteoroids. PhD Thesis, London: University of Western Ontario, p. 239; [11] McCrosky R.E., Posen A. (1961) SCoA 4, 15e84; [12] Matlovic P., et al. (2019) AA 629, A71eA90.

FIG 8.12

Finding chart of #33 versus N. and S. Taurids.

586

Anthelion source

September

September 4 (lo ¼ 162 )

215 NPI d Northern delta Piscids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, TJ ¼ þ4.79  0.56 Annual shower August 27eSeptember 16 (lo ¼ 153 e174 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 162.3 1.5 þ5.8 201.6 þ4.6 27.4 þ0.79 þ0.39 0.13 0.04 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.24 0.244 0.804 6.3 314.2 162.3 116.3 0.0308 0.045 1.56 2.72 4.72 2.72 þ0.0014 0.0002 þ0.04 0.25 þ1.00 þ0.75 ZHR ¼ 0.10/h (N ¼ 235, hr ¼ 50.8 , m(Mv ¼ 0) ¼ 0.19 g) c ¼ 3.16  0.12 (s ¼ 2.25  0.04) Component Ib meteoroids penetrate deep, KE < 82: Ib: Hb ¼ 99.3  1.54 Mv; Hmax ¼ 87.9 þ 0.48 Mv; He ¼ 81.6 þ 1.35 Mv (N ¼ 148) III: Hb ¼ 86.7  0.10 Mv; Hmax ¼ 81.6  0.19 Mv; He ¼ 78.2 þ 0.78 Mv (N ¼ 12) Ib: r w 1.2  0.9 g/cm3 (a1 ¼ 0.079 km, a2 ¼ 3.78/s) III: Irons or Na poor/free e e

Meteoroid density: Age: Source:

587

eV

Brief history: First reported from 1908 to 1938 visual observations by [1] from R.A. ¼ 0 , Decl. ¼ þ4 in the month centered on September 12 (lo ¼ 169 ), finding both a northern and southern branch. An anthelion shower called “Piscids” was isolated from September 1961 to 1965 Radio Meteor Project data with R.A. ¼ 0.8 , Decl. ¼ þ3.9 and Vg ¼ 27.4 km/s around lo ¼ 168.3 by [2] (Table I, p. 257), and from 1968 to 1969 data with R.A. ¼ 9.1 , Decl. ¼ þ7.2 and Vg ¼ 25.6 km/s around lo ¼ 173.5 by [3] (Table VI, p. 285). Those radiant positions are a little downrange and uprange, respectively, from the core of shower #33, but velocities are lower. Later photographic identifications by [4,5] had higher speed Vg ¼ 28.0e31.2 km/s, and these identifications pertain to early members of the Taurid complex (#17), instead (see Fig. 8.13). In velocity versus solar longitude diagrams, the Northern iota Aquariids (#33) stand out well from the Northern Taurids (#17). We assigned #215 here to a separate radiant close to the original “Piscids” position, seen among short-period asteroidal-type orbits (see plate). References: [1] Hoffmeister C. (1948) Meteorströme. Leipzig: Verlag Werden und Werken Weimar, 91 pp.; [2] Sekanina Z. (1973) Icarus 18, 257e259; [3] Sekanina Z. (1976) Icarus 27, 265e321; [4] Porubcan V., Gavajdova M. (1994) PSS 42, 151e155; [5] Jenniskens P., et al. (2016) Icarus 266, 331e354.

FIG 8.13

Identification of Northern (left) and Southern (right) Taurid Complex components.

588

Anthelion source

September

589

September 17 (lo ¼ 175 ) 925 EAN d eta Andromedids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ0.80  0.41 Annual shower September 6e26 (lo ¼ 164 e184 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 175.2 7.5 þ19.1 200.1 þ14.4 39.6 þ0.51 þ0.41 0.35 þ0.17 0.17 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.9 0.214 0.988 31.4 306.5 175.2 121.0 eV 0.0137 0.023 2.32 1.93 5.20 1.93 þ0.0064 0.0002 0.33 0.93 þ1.00 þ0.07 w0.05/h (N ¼ 122, hr ¼ 45.3 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.88  0.02 (s ¼ 2.15  0.01) Component Ib penetrate deep, KE < 82; II has low He, Ke < 79, like III. High III/II ratio may point to heating from low q: Ib: Hb ¼ 103.7  0.38 Mv; Hmax ¼ 92.7 þ 1.28 Mv; He ¼ 86.9 þ 1.83 Mv (N ¼ 32) II: Hb ¼ 97.3  0.48 Mv; Hmax ¼ 89.6 þ 0.88 Mv; He ¼ 84.8 þ 0.90 Mv (N ¼ 13) III: Hb ¼ 91.5 þ 0.19 Mv; Hmax ¼ 86.6 þ 0.96 Mv; He ¼ 82.6 þ 1.02 Mv (N ¼ 26) Ib: r w 1.3 g/cm3 (a1 ¼ 0.050 km, a2 ¼ 6.07/s) dpossibly Na poor/free III: r w 2.0 g/cm3 (a1 ¼ 0.089 km, a2 ¼ 6.64/s) From c and s: w9000 y e

Brief history: First reported by [1] from 8 CAMS-detected meteors from R.A. ¼ 12.4 , Decl. ¼ þ21.8 and Vg ¼ 38.2 km/s around lo ¼ 181.9 . Activity curve shown in Fig. 8.14. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

FIG 8.14

ZHR profile (scale uncertain).

590

Anthelion source

September

591

September 21 (lo ¼ 179 ) 216 SPI d Southern delta Piscids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density: Lightcurve shape: Age: Source:

Jupiter-family comet or asteroid, TJ ¼ þ5.21  0.65 Annual shower August 28eOctober 3 (lo ¼ 155 e191 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 178.8 22.7 þ4.5 203.3 4.6 26.4 þ0.78 þ0.33 0.15 þ0.01 þ0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.12 0.240 0.790 6.1 136.7 358.8 136.2 eV 0.0324 0.047 1.45 3.51 8.18 3.51 þ0.0007 þ0.0008 0.01 0.24 þ1.00 þ0.76 ZHR ¼ 0.2/h (N ¼ 758, hr ¼ 51.0 , m(Mv ¼ 0) ¼ 0.20 g) c ¼ 2.63  0.03 (s ¼ 2.05  0.01) Component Ib meteoroids penetrate deep, KE < 82: Ib: Hb ¼ 98.8  0.70 Mv; Hmax ¼ 87.7 þ 0.77 Mv; He ¼ 82.0 þ 1.31 Mv (N ¼ 456) IIb: Hb ¼ 90.4  0.08 Mv; Hmax ¼ 86.3 þ 0.11 Mv; He ¼ 80.3 þ 1.20 Mv (N ¼ 70) Ib: r w 1.5  0.3 g/cm3 (a1 ¼ 0.045 km, a2 ¼ 4.12/s) IIb: r w 4.1  0.9 g/cm3 (a1 ¼ 0.063 km, a2 ¼ 2.96/s) dNa poor/free IIb: low F ¼ 0.41, typical of irons e e

Brief history: An anthelion shower at R.A. ¼ 18.7 , Decl. ¼ þ5.2 and Vg ¼ 28.6 km/s around lo ¼ 183.0 was first identified from Adelaide radar data by [1] (Table 6, shower 61.9.1). A second, higher velocity, shower was identified at R.A. ¼ 20.3 , Decl. ¼ þ2.7 and Vg ¼ 31.9 km/s around lo ¼ 182.9 (Table 6, shower 61.9.6), corresponding to shower #2. Video data show a separate component at lower ecliptic longitude than #2 during this time [2]. In velocity (or longitude) versus solar longitude diagrams (see Fig. 8.15 below), the Southern iota Aquariids (#3) stand out well from the Southern Taurids (#2). I assigned #216 here to a separate radiant at higher longitude seen among asteroidal (short-period) orbits (see plate). References: [1] Nilsson C. S. (1964) AuJPh 17, 226e229; [2] Jenniskens P., et al. (2016) Icarus 266, 331e354.

FIG 8.15

SAAMER radar detection of shower #216.

592

Anthelion source

September

593

September 27 (lo ¼ 184 ) 714 RPI d rho Piscids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Jupiter-family comet, sunskirter, TJ ¼ þ3.08  0.50 Episodic shower September 13eOctober 13 1 (lo ¼ 170 e200 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 183.9 31.0 þ19.8 211.5 þ7.1 40.5 þ0.68 þ0.18 0.33 0.06 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.98 0.060 0.970 29.2 335.9 183.9 159.3 eV 0.0149 0.0140 6.08 3.09 7.06 3.09 þ0.0012 0.0002 0.51 0.30 þ1.00 þ0.70 w0.07 (N ¼ 243, hr ¼ 53.6 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.72  0.09 (s ¼ 2.09  0.04) II: Hb ¼ 98.6  0.59 Mv; Hmax ¼ 89.4 þ 1.09 Mv; He ¼ 84.8 þ 1.05 Mv (N ¼ 49) III: Hb ¼ 91.6  0.13 Mv; Hmax ¼ 86.7 þ 0.67 Mv; He ¼ 83.5 þ 0.61 Mv (N ¼ 116) dpossibly Na poor II: r w 1.3 g/cm3 (a1 ¼ 0.030 km, a2 ¼ 8.04/s) III: r w 2.2 g/cm3 (a1 ¼ 0.063 km, a2 ¼ 9.02/s) dpossibly Na free e e

Brief history: First isolated by [1] from R.A. ¼ 22.8 , Decl. ¼ þ16.9 and Vg ¼ 43.9 km/s around lo ¼ 177.0 . Northern component of #810. Higher entry velocity than #219 (Vg ¼ 37.5 km/s) and earlier activity period than #388. Sunskirter stream. Meteoroids have low beginning heights. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409. September 26 (lo ¼ 183 ) 810 XCD d October Cetids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density: Age: Source:

Jupiter-family comet, Machholz Complex, TJ ¼ þ3.14  0.54 Annual shower September 13eOctober 12 (lo ¼ 170 e199 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 183.0 35.2 þ5.7 211.8 8.0 39.9 þ0.59 þ0.25 0.35 þ0.04 0.10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.86 0.064 0.965 31.7 155.6 3.0 158.1 eV 0.0235 0.032 7.06 2.50 6.79 2.50 þ0.0029 0.0010 0.82 0.59 þ1.00 þ0.41 w0.04/h (N ¼ 131, hr ¼ 49.8 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.67  0.19 (s ¼ 2.07  0.08) Component IIb has low He, ke < 79, like III: IIb: Hb ¼ 96.7  0.32 Mv; Hmax ¼ 88.0 þ 1.03 Mv; He ¼ 83.2 þ 0.74 Mv (N ¼ 35) IIIb: Hb ¼ 90.5 þ 0.12 Mv; Hmax ¼ 86.2 þ 0.78 Mv; He ¼ 82.4 þ 0.94 Mv (N ¼ 45) IIb: r w 1.8 g/cm3 (a1 ¼ 0.097 km, a2 ¼ 5.45/s) IIIb: r w 1.9 g/cm3 (a1 ¼ 0.053 km, a2 ¼ 13.45/s) dpossibly Na free From c: 6400 y e

Brief history: Southern component of #714. First reported by [1] from 29 video-detected orbits by the BRAMON and SonotaCo networks having R.A. ¼ 38.0 , Decl. ¼ þ7.7 and Vg ¼ 39.8 km/s around lo ¼ 187.5 . Sunskirter stream. Meteoroids have low beginning heights. Name and number by [1]. References: [1] Amal L. S., et al. (2020) JIMO 48, 69e88.

594

Anthelion source

September

595

September 27 (lo ¼ 184 ) 219 SAR d September mu Arietids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source:

Mellish-type shower, sunskirter, TJ ¼ þ1.07  0.50 Annual shower September 8eOctober 11 (lo ¼ 165 e197 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 184.1 24.2 þ17.4 205.2 þ6.9 41.7 þ0.71 þ0.26 0.27 þ0.00 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 6.18 0.097 0.985 22.0 325.3 184.1 148.7 eV 0.0213 0.0170 4.73 3.55 6.73 3.55 þ0.0032 0.0002 0.52 0.62 þ1.00 þ0.38 w0.4/h (N ¼ 712, hr ¼ 54.8 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 3.97  0.18 (s ¼ 2.50  0.05) IIa: Hb ¼ 103.4  0.47 Mv; Hmax ¼ 94.1 þ 1.22 Mv; He ¼ 87.4 þ 1.91 Mv (N ¼ 279) III: Hb ¼ 94.4  0.09 Mv; Hmax ¼ 88.7 þ 0.89 Mv; He ¼ 83.9 þ 1.15 Mv (N ¼ 210) IIa: Low F ¼ 0.58, fragile; high IIa/III ratio: low-q heating IIa: r  1.0 g/cm3 (a1 ¼ 0.094 km, a2 ¼ 4.55/s), fragile: low a2 dNa poor III: r w 1.4 g/cm3 (a1 ¼ 0.090 km, a2 ¼ 7.25/s) dpossibly Na free Mg1.21 Fe0.87 Na0.023 (N ¼ 1), Na depleted From c and s: w6800 y e

Brief history: Adelaide radar detected shower (Table 6, shower 61.9.3) from 5 meteors radiating from R.A. ¼ 19.3 , Decl. ¼ þ15.6 and Vg ¼ 36.7 km/s around lo ¼ 179 [1]. Confirmed by Harvard Radio Meteor Project [2] and called “gamma Arietids” (Table 6, p. 285). Video-detected confirmation here. Name and number by [3]. References: [1] Nilsson C. S. (1964) AuJPh 17, 158e160; [2] Sekanina Z (1976) Icarus 27, 265e321; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp. September 24 (lo ¼ 181 ) 706 ZPI d zeta Piscids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age:

Jupiter-family comet, sunskirter, TJ ¼ þ3.00  0.39 Annual shower September 1eOctober 5 (lo ¼ 158 e192 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 181.1 26.9 þ12.7 208.5 þ1.6 38.7 þ0.81 þ0.30 0.15 0.01 þ0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.97 0.071 0.964 5.16 333.0 181.1 153.5 eV 0.0202 0.0188 2.36 3.09 7.30 3.09 þ0.0012 0.0002 0.09 0.29 þ1.00 þ0.71 w0.1/h (N ¼ 290, hr ¼ 52.0 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.78  0.05 (s ¼ 2.11  0.02) IIa: Hb ¼ 99.9  0.60 Mv; Hmax ¼ 90.3 þ 0.94 Mv; He ¼ 84.6 þ 1.35 Mv (N ¼ 89) III: Hb ¼ 92.9  0.04 Mv; Hmax ¼ 88.2 þ 0.91 Mv; He ¼ 83.2 þ 0.45 Mv (N ¼ 227) IIa: r w 1.7 g/cm3 (a1 ¼ 0.109 km, a2 ¼ 3.94/s) III: r w 2.0  0.9 g/cm3 (a1 ¼ 0.058 km, a2 ¼ 7.38/s) dpossibly Na poor/free From c: 7400 y

Brief history: First identified by [1] from 14 meteors radiating from R.A. ¼ 19.8 , Decl. ¼ þ9.7 and Vg ¼ 38.2 km/s around lo ¼ 172.0 . The shower merges into the onset of the Northern Taurid Complex at about lo ¼ 180 , but has a different l versus lo distribution. That onset is initially broad in l, but narrow in b, pointing to #706. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

596

Anthelion source

November

November 4 (lo ¼ 222 )

1167 FOD d 14 Orionids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ þ5.74  1.14 Annual shower October 14 d December 15 (lo ¼ 201 e 263 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 222.2 77.4 þ7.0y 214.3 15.7y 31.0 þ0.84 þ0.14 0.13 þ0.11 þ0.10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 0.97 0.159 0.845 33.0 147.9 42.2 189.9 0.0675 0.088 9.71 7.58 16.1 7.58 0.0020 0.0034 0.01 þ0.31 þ1.00 þ1.31 w0.06/h (N ¼ 551, hr ¼ 51.1 , m(Mv ¼ 0) ¼ 0.14 g) c ¼ 2.51  0.11 (s ¼ 2.02  0.05) Component II has low He, Ke < 79, like III: II: Hb ¼ 94.8  0.36 Mv; Hmax ¼ 86.2 þ 1.28 Mv; He ¼ 81.0 þ 1.75 Mv (N ¼ 325) II: r w 2.0  1.0 g/cm3 (a1 ¼ 0.079 km, a2 ¼ 5.07/s) e e

Meteoroid density: Age: Source:

597

eV

Brief history: First detected here. Figure 8.16 plots the radiant coordinates of meteors found along the toroidal arc during solar longitude 240e250 . Shower 810 has been excluded. The ecliptic latitude is given both as a function of time (left) and of position relative to sune centered ecliptic longitude (right). The 14eOrionids are marked in blue. Perhaps related to shower #19.

FIG 8.16

Identification of showers in direction of #610/#253.

598

Anthelion source

October

599

October 20 (lo ¼ 207 )

2 STA d Southern Taurids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.44  0.70 Annual shower Periodic outbursts by component #628 described elsewhere August 29eDecember 21 (lo ¼ 155 e270 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 207.0 40.1 þ10.7 193.9 4.7 27.8 þ0.74 þ0.16 0.26 0.04 0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.91 0.333 0.819 5.5 118.5 26.7 146.3 eV 0.0541 0.063 1.59 6.18 21.1 6.18 þ0.0044 0.0015 0.01 0.56 þ1.00 þ0.44 N ¼ 35,213 (hr ¼ 50.5 , m(Mv ¼ 0) ¼ 0.18 g) October 14 (lo ¼ 200.6 ) 3.7  0.5/h [23]; 5/h [22]; 2.2/h [9]; 11  2/h [24] c ¼ 2.95  0.13 (s ¼ 2.17  0.05); 2.3 [23] Component Ib meteoroids penetrate deep, KE < 79: Ib: Hb ¼ 99.5  0.99 Mv; Hmax ¼ 85.9 þ 1.44 Mv; He ¼ 80.2 þ 1.93 Mv (N ¼ 21,139) III: Hb ¼ 88.5  0.40 Mv; Hmax ¼ 82.9 þ 0.60 Mv; He ¼ 78.2 þ 1.05 Mv (N ¼ 1817) dchondritic Na Ib: r w 1.38  0.05 g/cm3 (a1 ¼ 0.088 km, a2 ¼ 3.31/s) III: r w 2.58  0.22 g/cm3 (a1 ¼ 0.080 km, a2 ¼ 5.90/s) dpossibly Na poor/free 0.01 ge0.1 g: r ¼ 1.8  0.2 g/cm3, K ¼ 32% [17]; 1e10 g: 1.6  0.4 g/cm3, 41% [18]; 6 ge700 kg: r ¼ 0.2e2 g/cm3, not function of strength parameter [26,27] 0.04  0.05 [15] All masses in range 6 ge700 kg have first fragmentation at rairV2 ¼ 0.01 MPa; 90% mass loss at 0.05 MPa, maximum pressure at 0.09 MPa [27]; Small 1 g meteoroids are strong, large 1 kg meteoroids fragile Mg0.89 Fe0.62 Na0.046 (N ¼ 16); AMOS: Mg1.00 Fe0.79 Na0.061 (N ¼ 11) [28]; Ib: most normal, but 7/33 are Fe poor and 2/33 are Fe poor þ Na rich [21] 4700 y (some more recent) [11]; 10,000 y [13]; Breakup of Encke: w5200 y [25]; w2000 [19]; 14,500 [29]; from c: w14,000 y; Encke in 7:2 res.: 9e20,000 y [29] 2P/Encke a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density:

Progressive fragmentation index: Strength:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB

Brief history: Visual observations during 1839e1849 by [1] first showed an active radiant at R.A. ¼ 55 , Decl. ¼ þ16 during November. Shower was rich in fireballs during Middle Ages [2]. [3] noticed the shower consisted of two branches, the Southern and Northern Taurids. Name “Taurids” in use by 1884 [4], number by [5]. First photographic determined radiant by [6]. Based on apparent trajectory was active in the 10th century. Radar observations at Jodrell Bank [7] initially did not separate the two Taurid branches. [8] did so with radar in 1960. [10] first noticed that activity profiles are not symmetric (Fig. 8.17). Association with comet 2P/Encke by [11]. First model by [12]. [13] modeled very large progenitor breakup 10,000 years ago, resulting in array of large asteroids associated with shower. [14] argued that most of those were stony S- and FIG 8.17 Activity profiles of Southern (left) and N. Taurids (right). O-type asteroids that arrived in 2P/

600

Anthelion source

Encke-like orbits by delivery from the main asteroid belt via the n6 resonance. Identified a number of shower components (Fig. 8.18). Agreed by [20]. Proposed alternative parent bodies (and a much younger Taurid age) included 2010 TU149 and 2003 WP21 [16], all have the a w2.2 AU of 2P/Encke. Recent review of observations by [24]. Model placing breakup of 2P at 3200 BCE by [25]. Refs. [25,29] found best fit to #2 from 2P/Encke being trapped in 7:2 mean motion resonance for period of time, with stream age 9e20 ka. References: [1] Heis E. (1867) AN 69, 158e159; [2] Astapovich I. S., Terentjeva A. K. (1968) In: Physics and Dynamics of Meteors. Eds: L. Kresák, P. M. Millman. Dordrecht: Reidel, pp. 316e317; [3] Tupman G. L. (1873) MNRAS 33, 298e307; [4] Cameron D. (1884) Nature 743, 287e288; [5] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [6] Wright F. W., Whipple F. L. (1950) Technical Rep. of Harvard College Obs., No. 6; [7] Hawkins G. S., Almond M. (1952) MNRAS 112, 223e233; [8] Kashcheyev B. L., Lebedinets V. N. (1963) SCoA 7, 183e199; [9] Molau S., et al. (2018) JIMO 46, 142e146; [10] Hindley K. B. (1972) JBAA 82, 287e298; [11] Whipple F. L. (1940) Proc. of the Am. Phil. Soc. 83, 711e745; [12] Whipple F. L., Hamid S. (1950) AJ 55, 185e186; [13] Steel D. I., et al. (1991) MNRAS 34, 485e490; [14] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, p. 455e471; [15] Jacchia L. G., et al. (1967) SCoA 10, 1e139; [16] Jenniskens P., et al. (2016) Icarus 266, 331e354; [17] Narziev M. (2019) PSS 173, 42e48; [18] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [19] Tomko D., Neslusan L. (2019) AA 623, A13eA37; [20] Popescu M., et al. (2014) AA 572, A106eA122; [21] Matlovic P. (2020) PhD Thesis. Bratislava: Comenius University, p. 41; [22] Rendtel J. (2022) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [23] Jenniskens P. (1994) AA 287, 990e1013; [24] Egal A. (2022) MNRAS 512, 2318e2336; [25] Egal A., et al. (2021) MNRAS 507, 2568e2591; [26] Shrbeny L., Spurny P. (2019) AA 629, A137eA147; [27] Borovicka J., Spurny P. (2020) PSS 182, id.104849; [28] Matlovic P., et al. (2019) AA 629, A71eA90; [29] Egal A., et al. (2022) MNRAS 515, 2800e2821.

FIG 8.18 Identification chart of components in the Southern Taurid Complex.

November

601

November 10 (lo ¼ 227 ) 17 NTA d Northern Taurids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Strength: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB

Jupiter-family comet, TJ ¼ þ3.18  0.29 Annual shower August 23eDecember 21 (lo ¼ 150 e270 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 227.3 56.6 þ22.3 191.6 þ2.5 28.2 þ0.83 þ0.20 0.19 0.00 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.15 0.360 0.833 2.9 293.6 227.3 161.7 eV 0.0430 0.051 1.32 5.31 18.0 5.31 þ0.0038 0.0018 0.04 0.44 þ1.00 þ0.56 N ¼ 29,601 (hr ¼ 55.4 , m(Mv ¼ 0) ¼ 0.18 g) November 11 (lo ¼ 227.8 ) 3.5  0.5/h [14]; 5/h [16]; 6  2/h [18]; 2.4  0.2/h [21]; 4.0  0.5 [22] c ¼ 2.72  0.06 (s ¼ 2.08  0.02); c ¼ 2.3 [15] Components Ib and II meteoroids penetrate deep, KE < 79: Ib: Hb ¼ 100.1  1.07 Mv; Hmax ¼ 85.1 þ 1.79 Mv; He ¼ 78.8 þ 2.41 Mv (N ¼ 14,719) II: Hb ¼ 93.3  1.00 Mv; Hmax ¼ 83.5 þ 1.30 Mv; He ¼ 78.2 þ 1.83 Mv (N ¼ 1058) III: Hb ¼ 87.8  0.39 Mv; Hmax ¼ 82.5 þ 0.61 Mv; He ¼ 78.2 þ 0.88 Mv (N ¼ 1038) r ¼ 1.8  0.2 g/cm3, porosity K ¼ 32% [12], 1.6  0.4 g/cm3, 41% [13] Ib: r w 1.35  0.05 g/cm3 (a1 ¼ 0.095 km, a2 ¼ 3.11/s) dchondritic Na II: r w 2.21  0.21 g/cm3 (a1 ¼ 0.0905 km, a2 ¼ 4.37/s) dNa poor dpossibly Na free III: r w 2.68  0.30 g/cm3 (a1 ¼ 0.082 km, a2 ¼ 6.49/s) low, cometary matter [8,10,11]; Max rairV2 ¼ 0.06 MPa (0.02e0.12 MPa) [20] Mg0.97 Fe0.75 Na0.060 (N ¼ 20); AMOS: Mg1.00 Fe1.13 Na0.052 (N ¼ 4) [23]; Mv  4: H lines (organic matter), variable Fe/Mg [10,11] From c: w11,000 y; w2000 y [13]; 2P breakup: 4500 y [5]; w5200 y, or if origin from 2P/Encke alone (trapped in 7:2 MMR for some time): 7e14,000 y [17] 2P/Encke a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Brief history: “Twin” shower of #2, but with a different activity profile (Fig. 8.17). Visual observers first noticed evening shower at R.A. ¼ 55 , Decl. ¼ þ16 [19]. [1] noticed the shower consisted of two branches, the Southern and Northern Taurids. First photographic determined radiant by [4]. Association with comet 2P/Encke by [4]. First model by [5]. [6] modeled very large progenitor breakup 10,000 years ago, associating many asteroids. [7] argued that most of those were stony S and O type asteroids that arrived in 2P/Encke-like orbits by delivery from the n6 resonance. Proposed parent bodies for younger Taurids include 2014 TG10 [7], 2005 TF50, and 2012 UR158 [9], all with a w2.2 AU of 2P/Encke. For recent models, see shower #2. Name “Taurids” by [2], number by [3]. References: [1] Tupman G. L. (1873) MNRAS 33, 298e307; [2] Greg R. P. (1875) Report of the Ann. Meeting of the British Ass. for the Adv. of Science 44, 269e359 (p. 337); [3] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [4] Whipple F. L. (1940) Proc. of the American Philosophical Soc. 83, 711e745; [5] Whipple F. L., Hamid S. (1950) AJ 55, 185e186; [6] Steel D. I., Asher D. J., Clube S. V. M. (1991) MNRAS 251, 632e648; [7] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [8] Jacchia L. G., Verniani F., Briggs R. E. (1967) SCoA 10, 1e139; [9] Jenniskens P., et al. (2016) Icarus 266, 331e354; [10] Borovicka J., et al. (2007) AA 473, 661e672; [11] Borovicka J., et al. (2019) In: Physical and Chemical Properties of Meteoroids. Cambridge: CUP, p. 37; [12] Narziev M. (2019) PSS 173, 42e48; [13] Babdzhanov P. B., Kokhirova G. I. (2009) AA 495, 353e358; [14] Tomko D., Neslusan L. (2019) AA 623, A13eA37; [15] Jenniskens P. (1994) AA 287, 990e1013; [16] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [17] Egal A., et al. (2021) MNRAS 507, 2568e2591; [18] Egal A. (2022) MNRAS 512, 2318e2336; [19] Heis E. (1867) AN 69, 158e159; [20] Shrbeny L., Spurny P. (2019) AA 629, A137eA147; [21] Molau S., et al. (2018) JIMO 46, 142e146; [22] Sergej I. (2020) eMeteorNews 5, 35e37; [23] Matlovic P., et al. (2019) AA 629, A71eA90.

602

Anthelion source

634 TAT d tau Taurids

November

603

November 6 (lo ¼ 224 )

628 STS d s Taurids

Dynamic type: Shower type: Years of outbursts:

Jupiter-family comet, TJ ¼ þ3.16  0.34 Episodic shower 1995 [3,4]; 1998 [5]; 2005 [7e9]; 2008 [10,16]; 2012 [11]; 2015 [1,12]; 2018/19 October 15eDecember 10 (lo ¼ 202 e259 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 223.5 54.0 þ14.5 191.2 4.8 27.8 þ0.57 þ0.04 0.44 0.08 0.28 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.14 0.372 0.826 5.3 112.4 43.5 156.8 eV 0.0285 0.045 1.02 3.42 8.16 3.42 þ0.0087 0.0043 0.03 0.98 þ1.00 þ0.02 N ¼ 8181 (hr ¼ 51.3 , m(Mv ¼ 0) ¼ 0.18 g) ZHR ¼ 4/h, but variable; 2005: w9/h on top of normal annual activity [7] c ¼ 2.11  0.12 (s ¼ 1.81  0.06); c ¼ 2.0  0.1 (s ¼ 1.75  0.05) [1] Component Ib penetrates deep, KE < 79, like III: Ib: Hb ¼ 100.1  1.37 Mv; Hmax ¼ 85.4 þ 1.66 Mv; He ¼ 79.4 þ 2.22 Mv (N ¼ 3506) III: Hb ¼ 87.7  0.63 Mv; Hmax ¼ 82.6 þ 0.27 Mv; He ¼ 77.7 þ 1.04 Mv (N ¼ 101) r w 1.32e2.54 g/cm3; rV2 ¼ 0.018e0.099 MPa [16] Ib: r w 1.60  0.11 g/cm3 (a1 ¼ 0.071 km, a2 ¼ 3.15/s) III: r w 1.98  0.49 g/cm3 (a1 ¼ 0.124 km, a2 ¼ 5.09/s) dpossibly Na free Mg0.85 Fe0.68 Na0.055 (N ¼ 2); 2/33 Na-enhanced, 7/33 Fe poor [16] Brighter than 7 mag: in strength-dominated regime [1]; PE < 8 mag: 2% I, 61% II, 20% IIIA, 17% IIIB; > 8 mag: 6% I, 94% II, 0% III [12] IIIB.

604

Anthelion source

November

605

References: [1] Devillepoix H. A. R., et al. (2021) Plan. Science Journal 2, 223e236; [2] Denning W. F. (1920) The Observatory 43, 432e433; [3] Spurny P. (1997) PSS 45, 541e555; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [5] Beech M., Hargrove M., Brown P. G. (2004) The Observatory 124, 277e284; [6] Asher D.J., Clube S. V.M. (1993) Quarterly J. of the Royal Astron. Soc. 34, 481e511; [7] Dubietis A., Arlt R. (2007) MNRAS 376, 890e894; [8] Shrbeny P., Spurny P. (2012) In: LPI Contribution 167. Asterois, Comets, Meteors 2012, id.6436; [9] Olech A., et al. (2017) MNRAS 469, 2077e2088; [10] Kanamori T., (2009) JIMO 37, 55e62; [11] Madiedo J. M., Ortiz J. I., Trigo-Rodríguez J. M., et al. (2014) Icarus 231, 356e368; [12] Spurny P., et al. (2017) AA 605, A68eA93; [13] Jenniskens P., et al. (2016) Icarus 266, 331e354; [14] Egal A., et al. (2021) MNRAS 507, 2568e2591; [15] Guennoun M., et al. (2019) AA 622, A84eA93; [16] Matlovic P., et al. (2017) PSS 143, 104e115; [16] Johannink C., Miskotte K. (2006) JIMO 34, 7e10.

September 27 (lo ¼ 183 ) 627 NPS d nu Piscids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB

[STA component]

Jupiter-family comet, TJ ¼ þ3.47  0.29 Annual shower September 8eOctober 15 (lo ¼ 165 e201 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 183.4 18.2 þ3.2 194.7 4.2 28.6 þ0.72 þ0.24 0.24 0.05 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.87 0.316 0.834 5.3 120.7 3.1 124.5 eV 0.0290 0.041 1.53 3.11 7.62 3.11 þ0.0046 0.0020 0.00 0.55 þ1.00 þ0.45 1.73 0.276 0.842 5.0 125.8 5.6 130.9 e V[1] ZHR ¼ 0.5/h (N ¼ 1784, hr ¼ 48.9 , m(Mv ¼ 0) ¼ 0.17 g) c ¼ 2.86  0.18 (s ¼ 2.14  0.04) Component Ib penetrates deep, KE < 82, IIa too has low He: Ke < 79: Ib: Hb ¼ 99.2  0.84 Mv; Hmax ¼ 87.6 þ 0.92 Mv; He ¼ 81.9 þ 1.41 Mv (N ¼ 1013) IIa: Hb ¼ 91.4  0.35 Mv; Hmax ¼ 86.3 þ 0.45 Mv; He ¼ 81.9 þ 0.72 Mv (N ¼ 127) IIIb: Hb ¼ 86.7 þ 0.23 Mv; Hmax ¼ 82.8 þ 0.79 Mv; He ¼ 78.1 þ 1.47 Mv (N ¼ 115) Ib: r w 1.61  0.29 g/cm3 (a1 ¼ 0.059 km, a2 ¼ 3.72/s) dpossibly Na poor IIa: r w 2.1  0.6 g/cm3 (a1 ¼ 0.060 km, a2 ¼ 5.64/s) IIIb: r w 2.7  0.7 g/cm3 (a1 ¼ 0.043 km, a2 ¼ 7.80/s) dpossibly Na free w2000 y [2]; from c: w12,000 y 2P/Encke a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Brief history: Radiant of Southern Taurids does not progress smoothly with each day, suggesting the shower is composed of components. Proposed narrow components in solar longitude by [1] were not confirmed after dataset grew larger and more continuous solar longitude coverage was achieved, but some groups remain recognized in radiant and speed clustering with time. Shower #627 groups early STA. [1] gave radiant at R.A. ¼ 25.5 , Decl. ¼ þ6.8 and Vg ¼ 29.4 km/s around lo ¼ 189.0 . Activity curve compared to all S. Taurid activity in Fig. 8.20. [2] concluded that features in Taurid Complex are due to dynamics of 2P. Name and number by [1]. FIG 8.20

References: [1] Jenniskens P., et al. (2016) Icarus 266, ZHR profile.

331e354; [2] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

606

Anthelion source

2 STAdSouthern Taurids

October

October 14 (lo ¼ 201 ) 28 SOA d Southern October delta Arietids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 2016-Oct-02.0 TDB Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB

607 [STA component]

Jupiter-family comet, TJ ¼ þ3.53  0.34 Annual shower October 1e19 (lo ¼ 188 e206 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 201.0 33.9 þ8.9 196.2 4.3 29.1 þ0.81 þ0.27 0.15 0.02 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.80 0.285 0.837 5.8 123.6 18.6 137.4 eV 0.0252 0.0227 1.42 3.15 4.12 3.15 þ0.0020 þ0.0002 0.00 0.33 þ1.00 þ0.67 1.75 0.286 0.834 5.7 124.6 15.4 139.8 e V[1] October 12 (lo ¼ 198.5 ) 2.4/h (N ¼ 6669, hr ¼ 49.4 , m(Mv ¼ 0) ¼ 0.16 g) c ¼ 2.94  0.11 (s ¼ 2.17  0.04) Meteoroids penetrate deep: Ib has Ke ¼ 79.0, IIa ke ¼ 79.7, and IIb Ke ¼ 104; Ib has KE ¼ 79.5, II 80.9, higher than other STA showers: Ia: Hb ¼ 107.1  1.91 Mv; Hmax ¼ 88.4 þ 1.56 Mv; He ¼ 79.5 þ 2.85 Mv (N ¼ 64) Ib: Hb ¼ 100.3  1.22 Mv; Hmax ¼ 86.5 þ 1.22 Mv; He ¼ 81.0 þ 1.71 Mv (N ¼ 1196) II: Hb ¼ 95.4  1.48 Mv; Hmax ¼ 86.9 þ 0.25 Mv; He ¼ 82.4 þ 0.45 Mv (N ¼ 143) III: Hb ¼ 86.8  0.07 Mv; Hmax ¼ 82.9 þ 0.27 Mv; He ¼ 79.6 þ 0.25 Mv (N ¼ 30) dpossibly Na enhanced Ia: r w 1.7  0.8 g/cm3 (a1 ¼ 0.043 km, a2 ¼ 3.77/s) Ib: r w 1.93  0.22 g/cm3 (a1 ¼ 0.0335 km, a2 ¼ 4.36/s) II: r w 2.7  0.8 g/cm3 (a1 ¼ 0.0365 km, a2 ¼ 4.98/s) dNa poor III: r w 2.5  0.6 g/cm3 (a1 ¼ 0.121 km, a2 ¼ 6.09/s) dpossibly Na free Mg0.93 Fe0.66 Na0.057 (N ¼ 4), chondritic w2000 y [2]; from c: w14,000 y 2P/Encke a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Brief history: At the core of the most intense part of the Southern Taurids #2 (Fig. 8.22). #2 and #624 have same radiant, but the first number refers to the overall Southern Taurid activity, while the latter is specific to a radiant at this solar longitude. Forms a complex with #28, which has a slightly higher entry speed. [1] gave radiant at R.A. ¼ 39.1 , Decl. ¼ þ10.5 and Vg ¼ 28.5 km/s around lo ¼ 205.0 . [2] concluded that features in Taurid Complex are due to dynamics of 2P and identified #624 with his model components C-S04 and S-S06. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

FIG 8.22

ZHR profile.

610

Anthelion source

October

611

October 26 (lo ¼ 214 )

626 LCT d lambda Cetids

[STA component]

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.42  0.32 Annual shower October 21eNovember 2 (lo ¼ 209 e220 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 214.4 45.8 þ12.3 192.5 4.8 27.4 þ0.79 þ0.21 0.20 0.02 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.98 0.359 0.813 5.4 115.2 34.4 149.6 eV 0.0345 0.025 1.13 4.47 2.57 4.47 þ0.0033 þ0.0007 0.02 0.45 þ1.00 þ0.55 1.94 0.345 0.821 5.5 116.5 35.1 151.7 e V[1] ZHR ¼ 2.1/h (N ¼ 3569, hr ¼ 51.5 , m(Mv¼ 0) ¼ 0.19 g) c ¼ 2.67  0.10 (s ¼ 2.07  0.03) Component Ib meteoroids penetrate deep, KE < 79: Ib: Hb ¼ 99.6  0.98 Mv; Hmax ¼ 85.8 þ 1.46 Mv; He ¼ 80.2 þ 1.88 Mv (N ¼ 2009) III: Hb ¼ 89.3  0.49 Mv; Hmax ¼ 82.9 þ 0.97 Mv; He ¼ 78.7 þ 1.25 Mv (N ¼ 144) Ib: r w 1.52  0.18 g/cm3 (a1 ¼ 0.051 km, a2 ¼ 3.57/s) III: r w 2.1  0.8 g/cm3 (a1 ¼ 0.128 km, a2 ¼ 5.12/s) dpossibly Na free w2000 y [4]; from c: w11,000 y 2007 RU17 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.04 0.346 0.830 9.2 130.8 16.6 147.4 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source: Epoch 2015-Oct-01.0 TDB

Brief history: From this component onwards (Fig. 8.23), velocity is gradually decreasing. [1] gave radiant at R.A. ¼ 48.1 , Decl. ¼ þ13.1 and Vg ¼ 27.9 km/s around lo ¼ 216.0 . Activity compared to that of all S. Taurids in Fig. 8.23. Association of 2007 RU17 with Taurids by [2]. Model by [3]. [4] concluded that features in Taurid Complex are due to dynamics of 2P and identified #626 with his model components C-S06 and S-S05. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Brown P., et al. (2010) Icarus 207, 66e81; [3] Bucek M., Porubcan V. (2013) In: Meteoroids 2013. Ed.: Jopek T. J., Rietmeijer F. J. M., Watanabe J., Williams I. P., Poznan: A.M. University, pp. 193e197; [4] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

FIG 8.23

ZHR profile.

612

Anthelion source

November

613

November 5 (lo ¼ 223 )

637 FTR d f Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.38  0.28 Annual shower November 1e10 (lo ¼ 218 e228 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 222.6 51.8 þ13.5 190.3 5.1 26.4 þ0.77 þ0.16 0.23 0.03 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.98 0.401 0.798 5.3 110.2 42.6 152.9 eV 0.0285 0.022 1.08 3.83 2.32 3.83 þ0.0038 0.0005 0.01 0.51 þ1.00 þ0.49 2.14 0.390 0.820 5.0 110.3 45.9 156.5 e V[1] ZHR ¼ 1.3/h (N ¼ 2118, hr ¼ 50.7 , m(Mv ¼ 0) ¼ 0.20 g) c ¼ 2.69  0.14 (s ¼ 2.07  0.04) Component Ib and II penetrate deep, KE < 79, like III: Ib: Hb ¼ 99.7  1.06 Mv; Hmax ¼ 85.0 þ 1.56 Mv; He ¼ 79.1 þ 2.11 Mv (N ¼ 1112) II: Hb ¼ 94.7  2.00 Mv; Hmax ¼ 83.4 þ 1.28 Mv; He ¼ 79.2 þ 1.59 Mv (N ¼ 82) III: Hb ¼ 86.9  0.55 Mv; Hmax ¼ 82.5 þ 0.13 Mv; He ¼ 76.0 þ 1.04 Mv (N ¼ 38) Ib: r w 1.87  0.19 g/cm3 (a1 ¼ 0.046 km, a2 ¼ 3.71/s) dpossibly Na poor II: r w 2.3  0.5 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 5.16/s) III: r w 2.6  0.9 g/cm3 (a1 ¼ 0.174 km, a2 ¼ 4.31/s) dpossibly Na free w2000 y [3]; from c: w13,000 y 2010 TU149 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.21 0.381 0.827 2.0 92.3 59.2 151.5 2005 UW6 2.05 0.534 0.740 0.88 181.0 334.5 155.5 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source: Epoch 2022-Jan-21.0 TDB Source: Epoch 2015-Oct-01.0 TDB

[STA component]

Brief history: Component in Southern Taurids. As a result of the daily drift, the Southern Taurid radiant first enters constellation of Taurus with this component. [1] gave radiant at R.A. ¼ 54.1 , Decl. ¼ þ14.6 and Vg ¼ 27.4 km/s around lo ¼ 225.0 . All Taurids show a range of beginning heights for a given brightness (Fig. 8.24). Association with Taurids by [2]. [3] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself. [4] proposed association with 2005 UW6. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Dumitru B. A., Birlan M., Popescu M., Nedelcu D. A. (2017) AA 607, A5eA27; [3] Tomko D., Neslusan L. (2019) AA 623, A13eA37; [4] Rudawska R., Vaubaillon J., Atreya P. (2012) AA 541, A2eA7.

FIG 8.24 Beginning height versus brightness.

614

Anthelion source

615

November

November 15 (lo ¼ 232 )

625 LTA d lambda Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.38  0.28 Annual shower November 10e22 (lo ¼ 227 e239 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 232.3 58.3 þ14.5 187.0 5.6 24.5 þ0.77 þ0.16 0.23 0.03 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.01 0.464 0.769 5.0 103.0 52.4 155.4 eV 0.0281 0.021 1.02 4.03 2.74 4.03 þ0.0038 0.0005 0.01 0.51 þ1.00 þ0.49 2.13 0.439 0.793 5.1 104.8 51.3 156.5 e V[1] ZHR ¼ 0.8/h (N ¼ 1361, hr ¼ 51.2 , m(Mv ¼ 0) ¼ 0.24 g) c ¼ 2.36  0.10 (s ¼ 1.94  0.05) Component Ib meteoroids penetrate deep, KE < 79: Ib: Hb ¼ 98.9  1.34 Mv; Hmax ¼ 83.1 þ 1.81 Mv; He ¼ 77.0 þ 2.39 Mv (N ¼ 644) III: Hb ¼ 86.5  0.67 Mv; Hmax ¼ 79.3 þ 1.32 Mv; He ¼ 73.5 þ 1.99 Mv (N ¼ 37) Ib: r w 2.38  0.40 g/cm3 (a1 ¼ 0.029 km, a2 ¼ 4.07/s) III: r w 2.5 g/cm3 (a1 ¼ 0.052 km, a2 ¼ 9.20/s) dpossibly Na free w2000 y [4]; from c: w8900 y; breakup of 2005 UR from Encke: 5200 y [4] 2005 UR a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.25 0.266 0.882 6.9 140.5 20.0 160.5 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2016-Oct-02.0 TDB Source: Epoch 2015-Oct-01.0 TDB

FIG 8.25

ZHR profile.

[STA component]

FIG 8.26

ZHR profile.

Brief history: Component in Southern Taurids. [1] gave radiant at R.A. ¼ 57.8 , Decl. ¼ þ14.8 and Vg ¼ 25.7 km/s around lo ¼ 231.0 . Activity curve of #637 in Fig. 8.26. Association of 2005 UR with Taurids by [2]. From model, [3] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself. Model by [4] has debris either due to dynamics of 2P, after several thousand years in 7:2 mean motion resonance, or from breakup of 2P/2005 UR about 5200 y ago. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Jopek T. J. (2011) Mem. Soc. Astron. Italiana 82, 310e320; [3] Tomko D., Neslusan L. (2019) AA 623, A13eA37; [4] Egal A., et al. (2021) MNRAS 507, 2568e2591.

616

Anthelion source

November

617

November 26 (lo ¼ 243 )

286 FTA d omega Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Year of outbursts: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.33  0.32 Annual shower November 22e29 (lo ¼ 239 e246 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 242.6 65.6 þ15.2 183.9 6.4 23.3 þ0.90 þ0.07 0.13 0.07 0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.09 0.515 0.755 5.2 96.4 62.6 158.7 eV 0.0395 0.034 0.92 5.07 1.48 5.07 þ0.0019 þ0.0003 þ0.04 0.29 þ1.00 þ0.71 2.10 0.517 0.751 5.1 96.2 62.7 158.2 e V[1] ZHR w 0.9/h (N ¼ 935, hr ¼ 52.7 , m(Mv ¼ 0) ¼ 0.27 g) best detection rates: 2007, 2011, 2016, 2020 c ¼ 2.16  0.02 (s ¼ 1.84  0.01) Component Ib meteoroids penetrate deep, KE < 79: Ib: Hb ¼ 98.1  1.29 Mv; Hmax ¼ 82.7 þ 1.70 Mv; He ¼ 76.3 þ 2.47 Mv (N ¼ 499) III: Hb ¼ 86.5  0.31 Mv; Hmax ¼ 79.4 þ 1.86 Mv; He ¼ 73.5 þ 3.15 Mv (N ¼ 26) Ib: r w 2.06  0.34 g/cm3 (a1 ¼ 0.047 km, a2 ¼ 3.64/s) dpossibly Na poor/free III: r w 3.1  1.4 g/cm3 (a1 ¼ 0.054 km, a2 ¼ 4.98/s) w2000 y [4]; from c: w6000 y; Earth through core of stream (sU < su) 2003 WP21 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.27 0.488 0.785 4.3 124.3 37.5 161.8 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source: Epoch 2015-Oct-01.0 TDB

[STA component]

Brief history: Component in Southern Taurids (Fig. 8.27). Stream identified by [1] from 2 similar short semi-major axis photographed orbits from R.A. ¼ 58.2 , Decl. ¼ þ16.8 and Vg ¼ 21.7 km/s around lo ¼ 240.2 . [2] adopted this name and gave the radiant at R.A. ¼ 65.2 , Decl. ¼ þ15.1 and Vg ¼ 23.3 km/s around lo ¼ 242.0 . Association of 2003 WP21 with Taurids by [2]. From photographed orbits, [3] isolated a Taurid Filament (“Tau 11”) with at R.A. ¼ 77 , Decl. ¼ þ18 and Vg ¼ 27 km/s and associated that filament with the same parent body. From model, [4] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself. Name and number by [1].

FIG 8.27

ZHR profile.

References: [1] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, Table 9, p. 750; [2] Jenniskens P., et al. (2016) Icarus 266, 331e354; [3] Porubcan V., Kornos L., Williams I. P. (2006) Contr. Astron. Obs. Skalnate Pleso 36, 103e117; [4] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

618

Anthelion source

October

619

October 21 (lo ¼ 208 )

25 NOA d Northern October delta Arietids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.35  0.39 Annual shower October 8e28 (lo ¼ 195 e215 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 208.0 38.9 þ18.0 194.5 þ2.8 28.8 þ0.89 þ0.25 0.11 0.03 0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.93 0.316 0.838 3.6 300.1 207.9 147.7 eV 0.0363 0.021 1.29 5.37 4.94 5.37 þ0.0024 0.0018 0.07 0.26 þ1.00 þ0.74 1.89 0.274 0.857 3.6 305.4 206.1 151.0 e V[1] 0.8/h (N ¼ 1656, hr ¼ 54.3 , m(Mv ¼ 0) ¼ 0.17 g) c ¼ 2.46  0.05 (s ¼ 1.98  0.02) Components I, Ib, and IIa penetrate deep, with low He and Ke < 79: I: Hb ¼ 104.6  1.81 Mv; Hmax ¼ 86.2 þ 1.76 Mv; He ¼ 79.0 þ 2.63 Mv (N ¼ 240) Ib: Hb ¼ 100.7  2.00 Mv; Hmax ¼ 86.4 þ 0.99 Mv; He ¼ 79.7 þ 1.91 Mv (N ¼ 469) IIa: Hb ¼ 96.4  1.94 Mv; Hmax ¼ 86.0 þ 0.70 Mv; He ¼ 80.5 þ 1.38 Mv (N ¼ 154) III: Hb ¼ 87.9  0.29 Mv; Hmax ¼ 83.0 þ 0.58 Mv; He ¼ 79.1 þ 0.74 Mv (N ¼ 91) I: r w 1.7  0.4 g/cm3 (a1 ¼ 0.052 km, a2 ¼ 3.83/s) Ib: r w 2.0  0.5 g/cm3 (a1 ¼ 0.052 km, a2 ¼ 4.07/s) IIa: r w 3.1  1.3 g/cm3 (a1 ¼ 0.023 km, a2 ¼ 6.37/s) dpossibly Na poor III: r w 2.5  0.9 g/cm3 (a1 ¼ 0.070 km, a2 ¼ 8.11/s) dpossibly Na free w2000 y [5]; from c and s: w7200 y 2P/Encke a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB

FIG 8.28

ZHR curve.

[NTA component]

Brief history: Weak component in Northern Taurids (Fig. 8.28). Traditionally, Taurids during October are called “Arietids.” From visual observations, [1] found “sigma Arietids” active during October from R.A. ¼ 41.9 ,  Decl. ¼ þ13.7 . Shower detected in Kharkiv radar data, from which [2] gave radiant at R.A. ¼ 34.7 , Decl. ¼ þ20.2 and Vg ¼ 36.3 km/s around lo ¼ 201.7 (shower 45). [3] grouped this detection with shower 45 of [4], based on photographed meteors radiating from R.A. ¼ 52.7 , Decl. ¼ þ18.2 and Vg ¼ 29.8 km/s around lo ¼ 222.4 , and assigned number and name. [5] adopted this name for a Northern Taurid component with radiant at R.A. ¼ 38.6 , Decl. ¼ þ17.8 and Vg ¼ 30.1 km/s around lo ¼ 205.0 . Activity as part of N. Taurids in Fig. 8.27. Parent body

is uncertain. From model, [6] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself. References: [1] Denning W. F. (1928) JBAA 38, 302; [2] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 11, 183e199; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 731; [4] Terentjeva A. K. (1989) In: Asteroids Comets Meteors III. Uppsala: Astronomical Observatory. pp. 579e584; [5] Jenniskens P., et al. (2016) Icarus 266, 331e354. [6] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

620

Anthelion source

October

621

October 30 (lo ¼ 217 )

631 DAT d delta Arietids

[NTA component]

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.20  0.49 Annual shower October 25eNovember 2 (lo ¼ 212 e220 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 216.6 48.9 þ20.5 195.2 þ2.3 29.9 þ0.85 þ0.23 0.17 þ0.01 0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.04 0.296 0.855 3.1 301.6 216.7 158.3 eV 0.0216 0.034 1.21 1.64 2.01 1.64 þ0.0031 0.0013 0.01 0.39 þ1.00 þ0.61 1.94 0.300 0.486 3.2 301.8 215.2 156.4 e V[1] ZHR ¼ 1.2/h (N ¼ 1512, hr ¼ 56.4 , m(Mv ¼ 0) ¼ 0.15 g) c ¼ 2.44  0.16 (s ¼ 1.97  0.07) Components Ib and II penetrate deep, KE < 79, like III: Ib: Hb ¼ 101.4  1.06 Mv; Hmax ¼ 86.4 þ 1.65 Mv; He ¼ 80.3 þ 2.10 Mv (N ¼ 731) II: Hb ¼ 95.8  1.29 Mv; Hmax ¼ 85.8 þ 1.10 Mv; He ¼ 80.4 þ 1.76 Mv (N ¼ 102) III: Hb ¼ 88.4  0.21 Mv; Hmax ¼ 83.3 þ 0.56 Mv; He ¼ 78.8 þ 0.90 Mv (N ¼ 32) Ib: r w 1.3  0.2 g/cm3 (a1 ¼ 0.081 km, a2 ¼ 3.22/s) dpossibly Na poor II: r w 1.8  0.5 g/cm3 (a1 ¼ 0.040 km, a2 ¼ 5.85/s) III: r w 2.0  1.1 g/cm3 (a1 ¼ 0.093 km, a2 ¼ 6.39/s) dpossibly Na free w2000 y [2]; from c: w6500 y 2P/Encke a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB

Brief history: Component in Northern Taurids (Fig. 8.29). At the onset of the core of the NTA. [1] gave radiant at R.A. ¼ 48.1 , Decl. ¼ þ20.4 and Vg ¼ 29.3 km/s around lo ¼ 216.0 . From model, [2] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Tomko D., Neslusan L. (2019) AA 623, A13eA37. FIG 8.29

ZHR profile.

622

Anthelion source

November

November 5 (lo ¼ 223 ) 630 TAR d tau Arietids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source: Epoch 2022-Aug-09.0 TDB Source: Epoch 2015-Oct-01.0 TDB

623 [NTA component]

Jupiter-family comet, TJ ¼ þ3.19  0.23 Annual shower November 1e8 (lo ¼ 219 e226 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 222.7 53.0 þ21.6 193.1 þ2.4 28.7 þ0.86 þ0.18 0.18 0.01 0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.08 0.336 0.839 3.0 296.9 222.8 159.8 eV 0.0201 0.013 1.05 1.79 1.29 1.79 þ0.0042 0.0016 0.03 0.52 þ1.00 þ0.48 1.96 0.341 0.824 3.1 296.6 220.4 156.7 e V[1] ZHR ¼ 2.4/h (N ¼ 2621, hr ¼ 54.5 , m(Mv ¼ 0) ¼ 0.17 g) c ¼ 2.11  0.05 (s ¼ 1.81  0.03) Components Ib and II penetrate deep, with low He and Ke < 79, like III: Ib: Hb ¼ 100.7  1.01 Mv; Hmax ¼ 85.9 þ 1.77 Mv; He ¼ 79.3 þ 2.46 Mv (N ¼ 1182) II: Hb ¼ 94.0  0.95 Mv; Hmax ¼ 83.4 þ 1.72 Mv; He ¼ 77.8 þ 2.38 Mv (N ¼ 67) III: Hb ¼ 87.9  0.32 Mv; Hmax ¼ 82.0 þ 1.06 Mv; He ¼ 77.8 þ 1.41 Mv (N ¼ 22) Ib: r w 1.36  0.18 g/cm3 (a1 ¼ 0.0955 km, a2 ¼ 3.01/s) dpossibly Na poor II: r w 2.3  0.8 g/cm3 (a1 ¼ 0.076 km, a2 ¼ 3.54/s) III: r w 3.0  0.8 g/cm3 (a1 ¼ 0.094 km, a2 ¼ 7.70/s) dpossibly Na free Mg1.27 Fe0.89 Na0.048 (N ¼ 1), chondritic w2000 y [5]; from c: w3300 y Breakup of 2005 TF50 from Encke: 5200 y [4] 2018 TY2 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.29 0.362 0.842 4.6 249.1 272.9 162.1 2005 TF50 2.26 0.289 0.872 10.9 160.4 0.3 160.7 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Brief history: Component in Northern Taurids (Fig. 8.30). [1] gave radiant at R.A. ¼ 50.0 , Decl. ¼ þ21.1 and Vg ¼ 28.1 km/s around lo ¼ 220.0 . Association of 2005 TF50 with Taurids by [2], but large rotation in node. Association with 2018 TY2 proposed here. Model by [3]. From other model, [2] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Porubcan V., Kornos L., Williams I. P. (2006) Contr. Astron. Obs. Skalnaté Pleso 36, 103e117; [3] Bucek M., Porubcan V. (2013) In: Meteoroids 2013. Eds.: Jopek T. J., et al., Poznan: A. M. University, pp. 193e197; [4] Egal A., et al. (2021) MNRAS 507, 2568e2591; [5] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

FIG 8.30

ZHR profile.

624

Anthelion source

November

November 11 (lo ¼ 229 ) 632 NET d November eta Taurids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2017-Nov-06.0 TDB Source: Epoch 2015-Oct-01.0 TDB

625 [NTA component]

Jupiter-family comet, TJ ¼ þ3.14  0.40 Annual shower November 8e13 (lo ¼ 226 e231 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 228.8 57.8 þ22.6 191.7 þ2.6 28.2 þ0.90 þ0.07 0.13 0.07 0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.14 0.357 0.834 2.8 293.9 228.8 162.7 eV 0.0195 0.033 1.07 1.55 1.22 1.55 þ0.0027 0.0001 0.03 0.33 þ1.00 þ0.67 2.11 0.357 0.827 2.8 294.3 227.1 161.3 e V[1] ZHR ¼ 3.4/h (N ¼ 2444, hr ¼ 56.4 , m(Mv ¼ 0) ¼ 0.18 g) c ¼ 2.09  0.14 (s ¼ 1.80  0.07) Components Ib and IIb penetrate deep, KE < 79, like III: Ib: Hb ¼ 100.5  1.09 Mv; Hmax ¼ 84.7 þ 1.96 Mv; He ¼ 78.5 þ 2.44 Mv (N ¼ 1206) II: Hb ¼ 93.9  1.39 Mv; Hmax ¼ 82.2 þ 1.70 Mv; He ¼ 76.8 þ 2.24 Mv (N ¼ 99) IIIb: Hb ¼ 85.6  0.32 Mv; Hmax ¼ 81.1 þ 0.39 Mv; He ¼ 77.0 þ 1.12 Mv (N ¼ 9) Ib: r w 1.45  0.17 g/cm3 (a1 ¼ 0.084 km, a2 ¼ 3.03/s) dpossibly Na poor II: r w 2.4  0.6 g/cm3 (a1 ¼ 0.138 km, a2 ¼ 4.71/s) IIIb: r w 2.8 g/cm3 (a1 ¼ 0.016 km, a2 ¼ 12.90/s) dpossibly Na free Mg2.10 Fe1.14 Na0.124 (N ¼ 1), chondritic, weak O emission w2000 y [4]; from c: w3200 y Breakup of 2004 TG10 from Encke: 5200 y [3] 2004 TG10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.23 0.308 0.862 4.0 299.3 223.2 162.5 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Brief history: At the core of Northern Taurids (Fig. 8.31). #17 and #632 have the same radiant, but #17 refers to the overall Northern Taurid activity, while #632 is the specific activity at this solar longitude. [1] gave radiant at R.A. ¼ 56.1 , Decl. ¼ þ22.3 and Vg ¼ 28.0 km/s around lo ¼ 227.0 . Association of 2004 TG10 with Taurids by [2]. From other model, [3] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself and specifically assigned #632 with component C-N01. Model by [4] has debris from breakup of 2P/2004 TG10 w5200 y ago, or from activity of 2P itself, specifically after residing for several thousand years in 7:2 mean motion resonance. Name and number by [1].

FIG 8.31

ZHR profile.

References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [3] Tomko D., Neslusan L. (2019) AA 623, A13eA37; [4] Egal A., et al. (2021) MNRAS 507, 2568e2591.

626 Anthelion source

FIG 8.32

Identification of components in the Northern Taurid Complex.

November

November 14 (lo ¼ 232 ) 635 ATU d A1 Taurids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-22.0 TDB Source: Epoch 2015-Oct-01.0 TDB

627 [NTA component]

Jupiter-family comet, TJ ¼ þ3.13  0.20 Annual shower November 11e17 (lo ¼ 229 e235 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 232.2 60.5 þ23.2 190.9 þ2.4 27.8 þ0.82 þ0.12 0.24 0.03 0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.17 0.374 0.827 2.7 291.9 232.2 164.1 eV 0.0168 0.011 1.01 2.52 1.47 2.52 þ0.0037 þ0.0000 0.05 0.53 þ1.00 þ0.47 2.16 0.381 0.819 2.6 291.2 231.2 162.3 e V[1] ZHR ¼ 2.2/h (N ¼ 2137, hr ¼ 55.4 , m(Mv ¼ 0) ¼ 0.18 g) c ¼ 2.28  0.09 (s ¼ 1.89  0.03) Components Ib and II meteoroids penetrate deep, KE < 79, like III: Ib: Hb ¼ 100.3  1.07 Mv; Hmax ¼ 84.5 þ 2.06 Mv; He ¼ 78.0 þ 2.75 Mv (N ¼ 999) II: Hb ¼ 94.6  1.26 Mv; Hmax ¼ 81.8 þ 1.72 Mv; He ¼ 76.9 þ 1.89 Mv (N ¼ 120) IIIb: Hb ¼ 86.2  0.44 Mv; Hmax ¼ 82.6  0.20 Mv; He ¼ 78.9  0.01 Mv (N ¼ 19) Ib: r w 2.34  0.23 g/cm3 (a1 ¼ 0.031 km, a2 ¼ 3.95/s) dpossibly Na poor II: r w 2.3  0.6 g/cm3 (a1 ¼ 0.059 km, a2 ¼ 4.56/s) IIIb: r w 2.0  0.8 g/cm3 (a1 ¼ 0.049 km, a2 ¼ 9.57/s) dpossibly Na free Mg1.35 Fe0.79 Na0.053 (N ¼ 1), chondritic w2000 y [3]; from c: w6000 y 2019 UN12 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.26 0.350 0.845 5.1 300.0 224.2 164.2 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Brief history: Component of Northern Taurids (Figs. 8.32). [1] gave radiant at R.A. ¼ 58.9 , Decl. ¼ þ22.8 and Vg ¼ 27.4 km/s around lo ¼ 231.0 . At the core of the NTA (Fig. 8.33). Model by [2], also proposed association with 2019 UN12. From other model, [3] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself and specifically assigned #635 with component S-N01 and S-N02. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Egal A., et al. (2021) MNRAS 507, 2568e2591; [3] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

FIG 8.33

ZHR profile.

628

Anthelion source

November

November 16 (lo ¼ 234 ) 629 ATS d A2 Taurids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source: Epoch 2015-Oct-01.0 TDB

629 [NTA component]

Jupiter-family comet, TJ ¼ þ3.21  0.19 Annual shower November 13e20 (lo ¼ 231 e238 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 234.3 61.8 þ23.5 189.9 þ2.5 26.9 þ0.90 þ0.07 0.13 0.07 0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.11 0.396 0.812 2.7 289.8 234.3 164.2 eV 0.0166 0.011 1.03 2.52 1.65 2.52 þ0.0024 þ0.0006 þ0.00 0.38 þ1.00 þ0.62 2.19 0.385 0.823 2.7 290.5 233.4 164.2 e V[1] ZHR ¼ 1.7/h (N ¼ 1815, hr ¼ 56.9 , m(Mv ¼ 0) ¼ 0.20 g) c ¼ 2.11  0.05 (s ¼ 1.81  0.02) Components Ib and IIa penetrate deep, KE < 79: Ib: Hb ¼ 100.3  1.13 Mv; Hmax ¼ 84.3 þ 1.94 Mv; He ¼ 77.9 þ 2.57 Mv (N ¼ 670) IIa: Hb ¼ 95.7  1.26 Mv; Hmax ¼ 82.7 þ 1.76 Mv; He ¼ 77.2 þ 2.11 Mv (N ¼ 163) III: Hb ¼ 87.6  0.05 Mv; Hmax ¼ 82.6 þ 0.77 Mv; He ¼ 77.6 þ 1.46 Mv (N ¼ 36) Ib: r w 2.51  0.33 g/cm3 (a1 ¼ 0.025 km, a2 ¼ 4.34/s) dpossibly Na poor IIa: r w 3.2  0.6 g/cm3 (a1 ¼ 0.032 km, a2 ¼ 4.62/s) III: r w 5.2  2.3 g/cm3 (a1 ¼ 0.011 km, a2 ¼ 9.93/s) dpossibly Na free Mg0.42 Fe0.23 Na0.026 (N ¼ 1), chondritic, strong O emission w2000 y [2]; from c: w3900 y 2014 NK52 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.21 0.357 0.838 2.5 270.5 254.4 165.0 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Brief history: Component in Northern Taurids (Figs. 8.32). [1] gave radiant at R.A. ¼ 60.7 , Decl. ¼ þ23.2 and Vg ¼ 27.5 km/s around lo ¼ 233.0 . At the core of the NTA (Fig. 8.34). Association with 2014 NK52 proposed here. From model, [2] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself and specifically assigned #629 with component R-N01. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

FIG 8.34

ZHR profile.

630

Anthelion source

635 ATUdA1 Taurids

November

November 21 (lo ¼ 237 ) 633 PTS d p Taurids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source: Epoch 2015-Oct-01.0 TDB

631 [NTA component]

Jupiter-family comet, TJ ¼ þ3.24  0.20 Annual shower November 15e26 (lo ¼ 234 e243 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 238.6 65.1 þ24.1 188.8 þ2.6 26.2 þ0.90 þ0.07 0.13 0.07 0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.10 0.419 0.801 2.6 287.2 238.5 165.9 eV 0.0176 0.012 1.07 2.71 2.26 2.71 þ0.0018 þ0.0012 0.04 0.33 þ1.00 þ0.67 2.21 0.413 0.812 2.5 287.2 238.6 166.5 e V[1] e (N ¼ 1474, hr ¼ 58.7 , m(Mv ¼ 0) ¼ 0.21 g) c ¼ 2.38  0.02 (s ¼ 1.94  0.01) Component Ib and IIa penetrate deep, KE < 79: Ib: Hb ¼ 100.2  1.26 Mv; Hmax ¼ 83.8 þ 2.04 Mv; He ¼ 77.4 þ 2.60 Mv (N ¼ 499) IIa: Hb ¼ 95.5  1.38 Mv; Hmax ¼ 82.7 þ 1.80 Mv; He ¼ 77.2 þ 2.16 Mv (N ¼ 130) III: Hb ¼ 86.8 þ 0.12 Mv; Hmax ¼ 81.2 þ 1.23 Mv; He ¼ 76.0  1.67 Mv (N ¼ 33) Ib: r w 2.50  0.33 g/cm3 (a1 ¼ 0.026 km, a2 ¼ 4.19/s) dpossibly Na poor IIa: r w 3.8  1.2 g/cm3 (a1 ¼ 0.025 km, a2 ¼ 5.58/s) III: r w 4.3  2.7 g/cm3 (a1 ¼ 0.071 km, a2 ¼ 5.30/s) dpossibly Na free Mg1.44 Fe0.98 Na0.081 (N ¼ 2), chondritic, weak O emission w2000 y [2]; from c: w8300 y 2012 UR158 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.24 0.319 0.857 3.2 238.9 286.9 165.8 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Brief history: Component in NTA (Fig. 8.32). [1] gave radiant at R.A. ¼ 66.7 , Decl. ¼ þ24.1 and Vg ¼ 26.7 km/s around lo ¼ 240.0 . Activity compared to all N. Taurids in Fig. 8.35. Association with 2012 UR158 made here. From model, [2] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

FIG 8.35

ZHR profile.

632

Anthelion source

November

633

Nov. 25 (lo ¼ 241 )

634 TAT d tau Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.17  0.39 Annual shower Nov. 20e28 (lo ¼ 237 e245 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 241.5 67.7 þ24.5 188.2 þ2.6 26.2 þ0.87 þ0.10 0.20 0.02 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.17 0.426 0.804 2.6 286.0 241.4 167.6 eV 0.0179 0.037 1.07 1.35 1.82 1.35 þ0.0041 0.0023 0.04 0.44 þ1.00 þ0.56 2.24 0.439 0.801 2.5 287.2 243.3 168.2 e V[1] ZHR ¼ 2.6/h (N ¼ 1492, hr ¼ 57.1 , m(Mv ¼ 0) ¼ 0.21 g) c ¼ 2.37  0.08 (s ¼ 1.94  0.03) Components Ib and II penetrate deep, KE < 79, like III: Ib: Hb ¼ 100.3  1.29 Mv; Hmax ¼ 83.9 þ 2.03 Mv; He ¼ 77.5 þ 2.50 Mv (N ¼ 633) II: Hb ¼ 94.7  1.49 Mv; Hmax ¼ 82.8 þ 1.59 Mv; He ¼ 77.7 þ 1.90 Mv (N ¼ 126) IIIb: Hb ¼ 85.7  0.15 Mv; Hmax ¼ 81.9 þ 0.47 Mv; He ¼ 77.4 þ 0.20 Mv (N ¼ 30) Ib: r w 1.48  0.25 g/cm3 (a1 ¼ 0.104 km, a2 ¼ 1.48/s) dpossibly Na poor II: r w 2.0  0.6 g/cm3 (a1 ¼ 0.058 km, a2 ¼ 4.05/s) IIIb: r w 4.1  1.5 g/cm3 (a1 ¼ 0.065 km, a2 ¼ 6.49/s) dpossibly Na free w2000 [4]; from c: w8300 y 2003 UL3 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.25 0.454 0.798 14.7 13.1 153.1 166.2 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source: Epoch 2015-Oct-01.0 TDB

[NTA component]

Brief history: Component in Northern Taurids (Fig. 8.32). [1] gave radiant at R.A. ¼ 69.7 , Decl. ¼ þ24.7 and Vg ¼ 25.8 km/s around lo ¼ 244.0 . Activity relative to all N. Taurids in Fig. 8.36. Association of Taurids with 2003 UL3 by [2]. Relatively large rotation of nodal line. From model, [4] concluded that features in Taurid Complex are due to dynamics of 2P ejecta itself and specifically assigned #634 with component C-N07 and E-N06. Spectrum (similar to 2P/ Encke) by [3]. Name and number by [1].

FIG 8.36

ZHR profile.

References: [1] Jenniskens P., et al. (2016) Icarus 266, 331e354; [2] Porubcan V., Kornos L., Williams I. P. (2006) Contr. Obs. Skalnaté Pleso 36, 103e117; [3] Tubiana C., et al. (2015) AA 584, A97eA108; [4] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

634

Anthelion source

December

635

December 1 (lo ¼ 249 )

257 ORS d Southern chi Orionids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.16  0.22 Annual shower November 6eDecember 21 (lo ¼ 224 e270 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 249.3 78.4 þ17.9 189.8 4.8 27.2 þ0.85 þ0.04 0.19 0.03 0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.17 0.398 0.817 5.1 109.0 69.3 177.8 eV 0.0463 0.072 1.20 4.25 11.09 4.25 þ0.0035 0.0012 0.02 0.42 þ1.00 þ0.58 N ¼ 4395 (hr ¼ 52.9 , m(Mv ¼ 0) ¼ 0.19 g) ZHR w 0.7/h c ¼ 2.34  0.03 (s ¼ 1.92  0.02) Component Ib meteoroids penetrate deep, with low He and Ke < 79, like III: Ib: Hb ¼ 99.3  1.03 Mv; Hmax ¼ 84.3 þ 1.94 Mv; He ¼ 77.7 þ 2.70 Mv (N ¼ 2148) III: Hb ¼ 87.1  0.25 Mv; Hmax ¼ 81.9 þ 1.09 Mv; He ¼ 77.0 þ 1.60 Mv (N ¼ 358) Ib: r w 1.47  0.18 g/cm3 (a1 ¼ 0.084 km, a2 ¼ 3.11/s) III: r w 3.2  0.5 g/cm3 (a1 ¼ 0.083 km, a2 ¼ 6.10/s) dNa poor/free Mg0.92 Fe0.54 Na0.074 (N ¼ 3), chondritic w2000 y [9]; from c: w 7300 y 2010 LU108 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.24 0.407 0.819 0.7 107.8 68.7 176.5 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB Source: Epoch 2015-Oct-01.0 TDB

Brief history: Part of c-Orionid Complex (#14) (Fig. 8.37). Shower stands out well from the Southern Taurids in late November and December. First detected in Adelaide radar observations by [1] (shower 60.12.3) from R.A. ¼ 91.6 , Decl. ¼ þ8.9 with Vg ¼ 26.9 km/s around lo ¼ 258.3 . Confirmed by [2]. Photographic shower recognized by [3] called “chi Orionids” with number 14 (now reserved for Complex), and included in Working List by [4], both as Southern c-Orionids (#257) and Northern c-Orionids (#256). Name by [3 and 4], number by [5]. Association 2010 LU108 by [6]. Model by [7,8]. Model by [9] identified shower as result of ejecta from 2P. References: [1] Nilsson C. S. (1964) AuJPh 17, 205e256; [2] Sekanina Z. (1973) Icarus 18, 253e284; [3] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [4] Cook A. F. (1973) NASSP 319, 183e191; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [6] Jenniskens P., et al. (2016) Icarus 266, 331e354. [7] Porubcan V., Williams I. P., Kornos L. (2004) EMP 95, 697e712; [8] Porubcan V., Kornos L., Williams I. P. (2006) Contr. Astron. Obs. Skalnaté Pleso 36, 103e117; [9] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

FIG 8.37

Finding chart of #257.

636

Anthelion source

257 ORSdSouthern chi Orionids

December

637

December 10 (lo ¼ 258 )

256 ORN d Northern chi Orionids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.15  0.23 Annual shower November 11eDecember 21 (lo ¼ 239 e270 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 258.0 88.4 þ25.5 190.0 þ2.2 27.6 þ0.93 þ0.03 0.16 þ0.01 0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.20 0.388 0.823 2.4 289.9 258.3 188.4 eV 0.0315 0.036 1.00 3.49 8.35 3.49 þ0.0029 0.0010 0.01 0.36 þ1.00 þ0.64 N ¼ 1326 (hr ¼ 59.7 , m(Mv ¼ 0) ¼ 0.18 g) December 19 (lo ¼ 267.5 ) ZHR w 0.3/h c ¼ 2.35  0.09 (s ¼ 1.93  0.04) Components Ib, IIa and IIb meteoroids penetrate deep, KE < 79: Ib: Hb ¼ 101.0  1.30 Mv; Hmax ¼ 85.2 þ 1.76 Mv; He ¼ 79.1 þ 2.30 Mv (N ¼ 432) IIa: Hb ¼ 96.7  1.26 Mv; Hmax ¼ 84.3 þ 1.47 Mv; He ¼ 77.4 þ 2.40 Mv (N ¼ 171) IIb: Hb ¼ 92.3  1.00 Mv; Hmax ¼ 83.1 þ 1.26 Mv; He ¼ 77.5 þ 2.00 Mv (N ¼ 97) IIIb: Hb ¼ 86.4  0.15 Mv; Hmax ¼ 82.4 þ 0.17 Mv; He ¼ 78.4 þ 0.66 Mv (N ¼ 67) Ib: r w 1.39  0.39 g/cm3 (a1 ¼ 0.088 km, a2 ¼ 3.13/s) dperhaps Na enhanced IIa: r w 1.7  0.9 g/cm3 (a1 ¼ 0.107 km, a2 ¼ 3.37/s) dNa poor IIb: r w 2.1  1.1 g/cm3 (a1 ¼ 0.088 km, a2 ¼ 5.74/s) IIIb: r w 3.2  0.8 g/cm3 (a1 ¼ 0.053 km, a2 ¼ 3.16/s) dpossibly Na free Mg1.41 Fe1.19 Na0.045 (N ¼ 1) w2000 y [10]; from c: w 7300 y 2002 XM35 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.33 0.377 0.838 3.1 312.6 230.0 182.6 2P/Encke 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB Source: Epoch 2015-Oct-01.0 TDB

FIG 8.38

ZHR profile for #257.

Brief history: Part of chi Orionid Complex (#14). Shower is close to but separate from Northern Taurids in late November and December. Detected by Harvard Meteor Radar by [1] from R.A. ¼ 97.0 , Decl. ¼ þ23.3 and Vg ¼ 28.7 km/s and by [2] from R.A. ¼ 83.4 , Decl. ¼ þ23.4 and Vg ¼ 26.2 km/s. Photographic shower recognized by [3] called “chi Orionids” with number 14 (now reserved for Complex), and included in Working List by [4], both as Southern chi Orionids (#257) and Northern chi Orionids (#256). Name by [3 and 4], number by [5]. Activity curve in Fig. 8.38. Association with 2002 XM35 made earlier by [6,7]. Association with 2008 XM1 by [8,9]. Model by [6,7]. Model by [10] identified 2P itself as source.

References: [1] Sekanina Z. (1973) Icarus 18, 253e284; [2] Sekanina Z (1976) Icarus 27, 265e321; [3] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [4] Cook A. F. (1973) NASSP 319, 183e191; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, 790 pp; [6] Porubcan V., Williams I. P., Kornos L. (2004) EMP 95, 697e712; [7] Porubcan V., Kornos L., Williams I. P. (2006) Contr. Astron. Obs. Skalnaté Pleso 36, 103e117; [9] Jenniskens P., et al. (2016) Icarus 266, 331e354; [9] Madiedo J. M., Trigo-Rodríguez J. M., Williams I. P., Ortiz J., Cabrera J. (2019) MNRAS 431, 2464e2470; [10] Tomko D., Neslusan L. (2019) AA 623, A13eA37.

638

Anthelion source

639

November

November 29 (lo ¼ 247 ) 250 NOO d November Orionids

Spectroscopy:

Mellish-type shower, sunskirter, TJ ¼ þ0.78  0.58 Annual shower November 1eDecember 21 (lo ¼ 218 e270 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 247.0 90.7 þ15.4 203.7 8.0 42.9 þ0.74 0.03 0.28 0.04 0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 14.7 0.114 0.992 24.4 140.7 67.0 207.7 eV 0.0248 0.0187 5.73 4.16 7.72 4.16 þ0.0035 þ0.0001 0.42 0.66 þ1.00 þ0.34 w4.5/h; 5/h [5] (N ¼ 8410, hr ¼ 52.2 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 3.56  0.09 (s ¼ 2.38  0.03); c steeper than for #19 [7]; c ¼ 3.0 [5] Component II has low He, Ke < 79, like III; High N III/II > heating from low q: Ib: Hb ¼ 105.0  0.75 Mv; Hmax ¼ 93.7 þ 1.62 Mv; He ¼ 87.8 þ 2.09 Mv (N ¼ 2372) II: Hb ¼ 99.6  0.46 Mv; Hmax ¼ 91.0 þ 1.35 Mv; He ¼ 85.5 þ 1.74 Mv (N ¼ 869) III: Hb ¼ 92.7 þ 0.12 Mv; Hmax ¼ 88.1 þ 0.98 Mv; He ¼ 84.0 þ 1.09 Mv (N ¼ 1904) Ib: r w 0.77  0.22 g/cm3 (a1 ¼ 0.098 km, a2 ¼ 4.61/s) II: r w 1.09  0.36 g/cm3 (a1 ¼ 0.113 km, a2 ¼ 5.31/s) dNa poor dNa free (high fraction) III: r w 1.91  0.39 g/cm3 (a1 ¼ 0.071 km, a2 ¼ 8.81/s) Mg1.01 Fe0.79 Na0.012 (N ¼ 7), Na depleted

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

November 1eDecember 21 (lo ¼ 221 e261 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 247.4 90.7 þ16.2 203.9 þ0.76 0.03 0.27 a (AU) q (AU) e i ( ) 3.93 0.098 0.979 24.5 0.0221 0.0178 5.31 þ0.0034 0.0007 0.46 N ¼ 904

Vg (km/s) 41.8 0.15 U ( ) 67.4 6.17 þ1.00

P ( ) 212.3 4.32 þ0.32

Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

Older than 5000 y, older than #19 [7]; from c and s: w7500 y C/1917 F1 (Mellish), or fragment a (AU) q (AU) e i ( ) u ( ) U ( ) 27.4 0.190 0.993 32.7 121.3 88.7

P ( ) 210.0

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

FIG 8.39

ZHR profile.

b ( ) 7.1 0.03 u ( ) 145.2 4.32 0.68

e R[M]

Brief history: Overlays shower #253 for lo < 240 , which has smaller entry speed and higher TJ. First detected by Adelaide radar from R.A. ¼ 96.1 , Decl. ¼ þ15.1 and Vg ¼ 40.6 km/s around lo ¼ 256.6 by [1] (Shower 60.12.9). Visual observer [6] saw 25 meteors in 10e15 min from R.A. ¼ 85 , Decl. ¼ þ4 (B1950) on November 25, 1964 (lo ¼ 244.12 ). Confirmed from Dutch Meteor Society low-light video observations by [2], who had R.A. ¼ 83.8 and þ15.3 and Vg ¼ 43.5 km/s. Also detected by CMOR radar by [3], with Vg ¼ 43.1 km/s. Activity curve in Fig. 8.39. Model by [7] has MON and NOO from same source, NOO before and MON after close encounter with Mercury or Venus. Name and number by [4].

References: [1] Nilsson C. S. (1964) AuJP 17, 205e256; [2] de Lignie M., Betlem H. (1997) Radiant, Journal of the DMS 19, 68e71; [3] Brown P., et al. (2010) Icarus 207, 66e81; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 736; [5] Rendtel J. (2021) 2002 Meteor Shower Calendar, Potsdam: IMO, p. 25; [6] Warner B. (1965) MNASSA 24, 126e127; [7] Veres P., et al. (2011) MNRAS 412, 511e521.

640

Anthelion source

December

641

December 11 (lo ¼ 259 ) 19 MON d December Monocerotids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

Mellish-type shower, TJ ¼ þ0.92  0.29 Annual shower November 24eDecember 27 (lo ¼ 242 e275 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 258.6 100.8 þ8.1 202.3 14.9 41.4 þ0.66 0.13 þ0.31 0.08 0.18 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.6 0.187 0.984 35.4 129.2 78.6 207.9 eV 0.0174 0.023 3.25 2.60 4.98 2.60 þ0.0047 0.0003 0.48 0.70 þ1.00 þ0.30 N ¼ 5710 (hr ¼ 49.4, m(Mv ¼ 0) ¼ 0.07 g) 2.0  0.4/h, B ¼ 0.25  0.10/ [10]; ZHR ¼ 3/h [11] c ¼ 2.91  0.06 (s ¼ 2.16  0.02); c ¼ 3.0 [11]; c ¼ 3.5 [10] Ib: Hb ¼ 104.6  0.97 Mv; Hmax ¼ 93.7 þ 1.43 Mv; He ¼ 88.4 þ 1.79 Mv (N ¼ 2546) II: Hb ¼ 99.6  0.56 Mv; Hmax ¼ 91.4 þ 1.33 Mv; He ¼ 87.0 þ 1.68 Mv (N ¼ 229) III: Hb ¼ 92.0 þ 0.27 Mv; Hmax ¼ 88.1 þ 0.84 Mv; He ¼ 83.6 þ 1.33 Mv (N ¼ 94) Ib: r w 0.71  0.11 g/cm3 (a1 ¼ 0.070 km, a2 ¼ 5.59/s) dchondritic Na II: r w 1.1  0.8 g/cm3 (a1 ¼ 0.077 km, a2 ¼ 6.21/s) dpossibly Na poor dpossibly Na free III: r w 2.5  1.1 g/cm3 (a1 ¼ 0.038 km, a2 ¼ 12.48/s) Mg1.24 Fe0.86 Na0.032 (N ¼ 8), only slightly Na depleted 20,000e30,000 y [8,9]; from c and s: w7700 y C/1917 F1 (Mellish) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 27.4 0.190 0.993 32.7 121.3 88.7 210.0

Brief history: First recognized by [1] from among the 144 meteor orbits measured by the Harvard College Observatory photographic survey from 1936 to 1951. Two meteors photographed on December 13 and 15, 1950, had R.A. ¼ 103 , Decl. ¼ þ8 . Results from their SuperSchmidt Project from 1952 to 1954 resulted in three meteors that belonged to the “Monocerotid” stream. First detected by the Adelaide radar by [3] with 2 meteors in 1960 and 6 meteors in 1961 from average radiant R.A. ¼ 101.6 , Decl. ¼ þ9.6 (Shower 61.12.7). Nearby November Orionids #250 created some confusion. [4] measured radiant motion from 15 FIG 8.40 ZHR profile. photographed orbits. [5,6] detected shower in low-light video data. Activity curve in Fig. 8.40. Association with C/1917 F1 made by [1]. Model by [7] showed ascending node varied by less than 5 between 783 CE and 3183 CE and nodal distance remained constant. Model by [12] shows MON and NOO have same source. Best match of peak time and radiant to model by [8] has age about 20,000e30,000 y, but [9] points out that meteoroids can be detected 4 members found scattered to higher longitude than #610, in an image opposite to #390 (early on) and #4 (during peak). Activity curve in Fig. 8.43. Name and number by [1].

FIG 8.43

ZHR profile (scale uncertain).

References: [1] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 200. [2] Jenniskens P., et al. (2016) Icarus 266, 331e354; [3] Jenniskens P., et al. (2018) PSS 154, 21e29.

648

Anthelion source

December

649

December 26 (lo ¼ 274 )

1097 DOH d December omega Hydrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, sunskirter, TJ ¼ þ0.42  0.51 Annual shower December 19eJanuary 1 (lo ¼ 267 e280 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 273.8 135.3 þ3.1 222.7 13.2 54.1 þ0.64 0.24 0.30 0.04 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.96 0.101 0.989 113.7 143.8 93.8 237.7 eV 0.0111 0.0093 3.56 2.72 2.82 2.72 0.0017 þ0.0006 1.16 þ0.29 þ1.00 þ1.29 w0.04/h (N ¼ 68, hr ¼ 50.9 , m(Mv ¼ 0) ¼ 0.03 g) c ¼ 2.49  0.07 (s ¼ 1.99  0.03) Component IIb has low He, ke < 79, like III: IIb: Hb ¼ 98.5  0.06 Mv; Hmax ¼ 93.5 þ 0.57 Mv; He ¼ 87.6 þ 0.73 Mv (N ¼ 38) dpossibly Na poor/free IIb: r w 1.9 g/cm3 (a1 ¼ 0.122 km, a2 ¼ 5.58/s) From c and s: w5100 y; high dP/dlo versus i e

Meteoroid density: Age: Source:

Brief history: First described here. December 31 (lo ¼ 279 )

644 JLL d January lambda Leonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, possible part of Phaethon Complex, TJ ¼ þ3.02  0.44 Annual shower December 21eJanuary 9 (lo ¼ 270 e288 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 278.8 132.0 þ24.8 208.7 þ6.6 39.5 þ0.98 0.29 0.08 0.04 0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.94 0.086 0.957 21.6 330.4 278.8 249.1 eV 0.0342 0.0240 6.33 7.65 4.96 7.65 þ0.0005 0.0002 0.20 0.08 þ1.00 þ0.92 w0.3/h (N ¼ 969, hr ¼ 60.2 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.47  0.07 (s ¼ 1.98  0.03) High III/II ratio > low q heating? Component IIa has low He, Ke < 79, like III: II: Hb ¼ 99.8  0.52 Mv; Hmax ¼ 90.3 þ 1.47 Mv; He ¼ 84.7 þ 2.00 Mv (N ¼ 209) III: Hb ¼ 93.0  0.38 Mv; Hmax ¼ 88.0 þ 0.55 Mv; He ¼ 83.6 þ 0.76 Mv (N ¼ 273) II: r w 1.4 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 6.13/s) dpossibly Na poor III: r w 3.6  2.0 g/cm3 (a1 ¼ 0.044 km, a2 ¼ 9.85/s) dpossibly Na free From c: 10,000 y e

Meteoroid density: Age: Source:

Brief history: Follows #641 in solar longitude. First described by [1] with R.A. ¼ 140.2 , Decl. ¼ þ23.4 and Vg ¼ 38.6 km/s around lo ¼ 288.0 . Very similar shower (#747) found by [2] with R.A. ¼ 141.9 , Decl. ¼ þ21.5 and Vg ¼ 39.5 km/s around lo ¼ 287.6 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409; [2] Jenniskens P., et al. (2018) PSS 154, 21e29.

650

Anthelion source

December

651

December 30 (lo ¼ 279 )

1121 LAD d December alpha Lyncids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, sunskirter, TJ ¼ þ0.26  0.53 Annual shower December 28eJanuary 5 (lo ¼ 277 e285 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 279.4 140.9 þ33.5 213.4 þ17.3 49.3 þ0.98 0.29 0.08 0.00 þ0.21 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 40.7 0.130 0.997 73.5 317.5 279.2 236.6 eV 0.0065 0.0121 3.08 1.85 1.57 1.85 þ0.0001 0.0017 0.66 þ0.14 þ1.00 þ1.14 w0.01/h (N ¼ 20, hr ¼ 74.0 , m(Mv ¼ 0) ¼ 0.04 g) c w 2.37 (s ¼ w1.94) IIa: Hb ¼ 105.9  0.00 Mv; Hmax ¼ 91.7 þ 4.39 Mv; He ¼ 87.5 þ 4.35 Mv (N ¼ 7) IIa: r w 0.21 g/cm3 (a1 ¼ 0.173 km, a2 ¼ 4.89/s) duncertain due to low N From c and s: w5200 y e

Brief history: First identified by [1] from cluster analysis of 2007e2020 SonotaCo data. Four triangulated meteors radiated from R.A. ¼ 140.5 , Decl. ¼ þ33.7 and Vg ¼ 49.6 km/s around lo ¼ 278.9 . Name and number by [1]. References: [1] Kanamori T., Uehara S., Sekiguchi T., Fujiwara Y., Maeda K., Ueda M. (2022) JIMO 49, 76e97. December 27 (lo ¼ 276 )

1170 LTM d 10 Leonis Minorids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Long-period comet, TJ ¼ þ0.36  0.65 Episodic shower 2009, 2013e2019 December 22eJanuary 1 (lo ¼ 271 e280 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 275.8 143.0 þ37.2 216.5 þ21.3 50.2 þ1.04 0.61 þ0.06 0.31 þ0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 20.5 0.189 0.992 82.2 309.1 275.8 223.7 eV 0.0211 0.0250 2.66 3.79 2.79 3.79 0.0047 þ0.0008 þ0.43 þ0.65 þ1.00 þ1.65 w0.02/h (N ¼ 29, hr ¼ 63.2 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 2.47  0.12 (s ¼ 1.98  0.05) IIa: Hb ¼ 103.6  1.54 Mv; Hmax ¼ 93.8 þ 1.40 Mv; He ¼ 90.1 þ 0.77 Mv (N ¼ 15) dpossibly Na free (low N) IIa: r w 4.0 g/cm3 (a1 ¼ 0.014 km, a2 ¼ 5.92/s) From c and s: w9700 y e

Brief history: First identified here. Detected in 2009, 2013e2019, but not in 2020e2021.

652

Anthelion source

653

January

January 3 (lo ¼ 282 )

319 JLE d January Leonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, sunskirter, TJ ¼ þ0.80  0.50 Annual shower December 22eJanuary 9 (lo ¼ 270 e288 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 282.0 147.1 þ24.0 219.5 þ10.1 52.2 þ0.51 0.20 0.48 0.03 0.34 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 6.64 0.050 0.993 104.5 334.8 282.0 257.0 eV 0.0152 0.0102 8.43 4.26 3.41 4.26 0.0036 0.0001 2.54 þ0.84 þ1.00 þ1.84 w0.4/h (N ¼ 315, hr ¼ 58.5 , m(Mv ¼ 0) ¼ 0.04 g) c ¼ 3.71  0.20 (s ¼ 2.42  0.06) Component IIb has low He: Ke < 79, like III; high III/II ratio (low q heating): IIb: Hb ¼ 97.9  0.15 Mv; Hmax ¼ 92.3 þ 0.61 Mv; He ¼ 87.8 þ 0.74 Mv (N ¼ 62) III: Hb ¼ 94.9  0.02 Mv; Hmax ¼ 91.2 þ 0.31 Mv; He ¼ 86.8 þ 0.64 Mv (N ¼ 140) IIb: F ¼ 0.55, III: F ¼ 0.46 IIb: r w 0.92 g/cm3 (a1 ¼ 0.055 km, a2 ¼ 6.25/s) dpossibly Na poor III: r w 2.4 g/cm3 (a1 ¼ 0.039 km, a2 ¼ 12.00/s) dpossibly Na free From c and s: w3400 y; high dP/dlo versus i e

Lightcurve shape: Meteoroid density: Age: Source:

FIG 8.44

Brief history: Shower has low perihelion distance q w 0.05 AU. Height distribution is shown in Fig. 8.44, with dashed line a leastsquares fit. Lower component is typical of sodium “free” particles, with beginning height nearly independent of meteor magnitude over this range. First described from 138 measured CMOR radar orbits by [1] with R.A. ¼ 148.3 , Decl. ¼ 23.9 and Vg ¼ 52.7 km/s around lo ¼ 282.5 . Detected in singlestation video observations by [2,4]. Confirmed from triangulated low-light video observations by [3]. Possible wing to higher ecliptic longitude and latitude, with velocity increasing to higher longitude. Radar shower #1190 is part of this structure. Name and number by [1]. Height distribution.

References: [1] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [2] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Molau S., et al. (2013) JIMO 41, 61e66. January 18 (lo ¼ 298 )

708 RLM d R Leonis Minorids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR:

Mellish-type shower, toroidal shower, TJ ¼ þ1.08  0.28 Annual shower January 11e26 (lo ¼ 291 e306 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 298.3 151.6 þ34.7 202.8 þ21.5 þ0.71 0.27 0.31 0.03 a (AU) q (AU) e i ( ) u ( ) 8.66 0.259 0.970 44.1 299.8 0.0152 0.0218 2.22 2.79 þ0.0028 þ0.0010 0.52 0.43 w0.05/h (N ¼ 111, hr ¼ 68.3 , m(Mv ¼ 0) ¼ 0.07 g)

Vg (km/s) 41.0 0.11 U ( ) 298.3 3.55 þ1.00

P ( ) 237.9 2.79 þ0.57

eV

654

Anthelion source

January

January 19 (lo ¼ 299 )

708 RLM d R Leonis Minorids (cont.)

Magn. distribution index: Lightcurve:

c ¼ 2.59  0.18 (s ¼ 2.03  0.07) Ib: Hb ¼ 105.1  0.81 Mv; Hmax ¼ 95.1 þ 0.84 Mv; He ¼ 90.4 þ 1.26 Mv (N ¼ 86) III: Hb ¼ 94.3  0.21 Mv; Hmax ¼ 89.6 þ 0.50 Mv; He ¼ 85.5 þ 1.02 Mv (N ¼ 11) F ¼ 0.68 Ib: r w 0.90  0.40 g/cm3 (a1 ¼ 0.032 km, a2 ¼ 5.99/s) From c and s: w7600 y e

Lightcurve shape: Meteoroid density: Age: Source:

655

Brief history: First reported from low-light video observations by [1] with R.A. ¼ 148.6 , Decl. ¼ 36.4 and Vg ¼ 40.9 km/s around lo ¼ 293.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409. January 5 (lo ¼ 285 )

96 NCC d Northern delta Cancrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.10  0.24 Annual shower December 22eJanuary 23 (lo ¼ 270 e300 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 285.1 118.6 þ23.3 190.7 þ2.4 28.3 þ0.87 0.18 0.18 0.02 0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.20 0.375 0.830 2.79 291.5 285.1 217.6 eV 0.0306 0.037 0.94 3.29 7.49 3.29 þ0.0033 0.0013 0.04 0.39 þ1.00 þ0.61 w0.06/h (N ¼ 441, hr ¼ 58.0 , m(Mv ¼ 0) ¼ 0.17 g) c ¼ 2.37  0.09 (s ¼ 1.94  0.04) Components Ib and II meteoroids penetrate deep, KE < 79, like shower NTA: Ib: Hb ¼ 100.7 þ 1.70 Mv; Hmax ¼ 85.5 þ 1.69 Mv; He ¼ 79.7 þ 2.36 Mv (N ¼ 138) II: Hb ¼ 94.1  1.67 Mv; Hmax ¼ 84.3 þ 1.52 Mv; He ¼ 78.2 þ 2.49 Mv (N ¼ 40) IIIb: Hb ¼ 86.5 þ 0.48 Mv; Hmax ¼ 82.6 þ 1.00 Mv; He ¼ 78.6 þ 0.95 Mv (N ¼ 26) Ib: r w 1.4  1.0 g/cm3 (a1 ¼ 0.098 km, a2 ¼ 3.30/s) dchondritic II: Possibly Na poor; III: Possibly Na free Mg1.65 Fe1.78 Na0.060 (N ¼ 1), weak O emission e 2P/Encke a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2015-Sep-16.0 TDB

Brief history: Part of Taurid Complex, after showers #17 and #256 have moved westwards. [1] first detected the d-Cancrids from 7 similar photographed orbits radiating from R.A. ¼ 126 , Decl. ¼ þ20 and Vg ¼ 28 km/s during January 13e21. This combination of showers #96 and #97 was subsequently detected in Harvard Radio Meteor Project radar data by [2] from R.A. ¼ 124.8 , Decl. ¼ þ20.8 and Vg ¼ 25.8 km/s around lo ¼ 292.9 and by [3] from R.A. ¼ 130.7 , Decl. ¼ þ19.7 with Vg ¼ 26.4 around lo ¼ 297.1 . Separated in Northern and Southern branches in line with Northern and Southern Taurids in Working List by [4]. Northern component detected in single-station video by [6]. Both components confirmed from triangulated video data by [7]. Link with 1991 AQ by [4,5]. Link with 2P/ Encke here. Name by [1,4] and number by [4]. References: [1] Lindblad B. A. (1971) SCoA 12, 14e24; [2] Sekanina Z. (1973) Icarus 18, 257e259; [3] Sekanina Z. (1976) Icarus 27, 265e321; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP p. 693; [5] Ye Q.-Z. (2018) PSS 164, 7e12; [6] Molau S., et al. (2013) JIMO 41, 61e66; [7] Jenniskens P., et al. (2016) Icarus 266, 331e354.

656

Anthelion source

97 SCCdSouthern delta Cancrids

657

January

January 1 (lo ¼ 281 )

97 SCC d Southern delta Cancrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.07  0.20 Annual shower December 22eJanuary 22 (lo ¼ 270 e300 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 280.9 112.2 þ17.1 188.9 4.7 27.2 þ0.85 0.14 0.17 0.01 0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.23 0.411 0.816 4.89 107.2 100.9 210.2 eV 0.0313 0.035 0.84 3.56 8.03 3.56 þ0.0031 0.0010 0.03 0.36 þ1.00 þ0.64 w0.1/h (N ¼ 581, hr ¼ 53.3 , m(Mv ¼ 0) ¼ 0.19 g) c ¼ 2.86  0.10 (s ¼ 2.14  0.04) Components Ib and II meteoroids penetrate deep, KE < 79, like shower STA: Ib: Hb ¼ 99.7  1.24 Mv; Hmax ¼ 85.4 þ 1.88 Mv; He ¼ 79.4 þ 2.59 Mv (N ¼ 208) II: Hb ¼ 92.9  0.40 Mv; Hmax ¼ 84.2 þ 1.24 Mv; He ¼ 79.0 þ 2.05 Mv (N ¼ 51) III: Hb ¼ 88.1  0.33 Mv; Hmax ¼ 83.9 þ 0.19 Mv; He ¼ 79.5 þ 0.53 Mv (N ¼ 47) Ib: r w 1.5  0.7 g/cm3 (a1 ¼ 0.059 km, a2 ¼ 3.76/s) dchondritic II: Possibly Na poor; III: Possibly Na free Mg0.74 Fe0.53 Na0.043 (N ¼ 2), chondritic e 2P/Encke a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.22 0.336 0.848 11.8 186.5 334.6 161.1

Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2015-Sep-16.0 TDB

Brief history: Part of Taurid Complex, follows after #2 and #257 have moved westwards. [1] first detected the d-Cancrids from 7 similar photographed orbits radiating from R.A. ¼ 126 , Decl. ¼ þ20 and Vg ¼ 28 km/s during January 13e21. The combination of showers #96 and #97 was detected in Harvard Meteor Project radar data by [2] from R.A. ¼ 124.8 , Decl. ¼ þ20.8 and Vg ¼ 25.8 km/s around lo ¼ 292.9 and by [3] from R.A. ¼ 130.7 , Decl. ¼ þ19.7 with Vg ¼ 26.4 around lo ¼ 297.1 . Split in Northern and Southern branches in Working List by [3], but Southern branch poorly documented. Southern branch confirmed from single-station data by [6] over lo ¼ 294e298 interval, and from triangulated video observations by [5]. Activity curve in Fig. 8.45. Link with 2001 YB5 proposed by [3,4]. Link with 2P/Encke here. Name by [1,3] and number by [3]. References: [1] Lindblad B. A. (1971) SCoA 12, 14e24; [2] Sekanina Z. (1973) Icarus 18, 257e259; [3] Sekanina Z. (1976) Icarus 27, 265e321; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP p. 693; [4] Ye Q.-Z. (2018) PSS 164, 7e12; [5] Jenniskens P., et al. (2016) Icarus 266, 331e354; [6] Molau S., Rendtel J. (2009) JIMO 37, 98e121.

FIG 8.45

ZHR profile (scale uncertain).

658

Anthelion source

January

659

January 10 (lo ¼ 289 )

643 OLS d omega Leonids

Dynamic type: Year of outbursts: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, sunskirter, TJ ¼ þ0.80  0.47 2015: lo ¼ 289.315 , ZHR ¼ 13  2/h, W ¼ 0.027 , c w 3.0 [2,3] Annual shower with episodic outbursts January 3e19 (lo ¼ 282 e298 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 289.5 138.7 þ8.5 208.7 7.1 46.1 þ0.70 0.14 0.29 þ0.06 0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.93 0.054 0.995 33.9 153.2 109.5 263.0 eV 0.0169 0.0086 9.10 4.54 3.40 4.54 þ0.0017 þ0.0002 1.16 0.53 þ1.00 þ0.47 N 0.055 1.000 35.0 152.6 109.5 262.1 e R[1] Annual: w0.1/h (N ¼ 224, hr ¼ 46.5 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 2.69  0.06 (s ¼ 2.07  0.03) Near-continuous distribution. High III/II ratio > heating from low q?: II: Hb ¼ 100.6 þ 1.10 Mv; Hmax ¼ 94.7 þ 2.47 Mv; He ¼ 88.5 þ 2.48 Mv (N ¼ 43) III: Hb ¼ 95.4 þ 0.13 Mv; Hmax ¼ 88.8 þ 1.56 Mv; He ¼ 84.5 þ 1.61 Mv (N ¼ 57) II: Low F ¼ 0.49, fragile II: r  1.8 g/cm3 (a1 ¼ 0.026 km, a2 ¼ 7.46/s), lower if fragile dNa free III: r w 1.7 g/cm3 (a1 ¼ 0.076 km, a2 ¼ 7.92/s) dpossibly Na free Mg1.45 Fe0.84 Na0.005 (N ¼ 1), Na depleted AMOS: Mg1.00 Fe0.38 Na0.005 (N ¼ 1) [4] From c and s: w2700 y, core stream: sU < su 793 KCA d kappa Cancrids

Lightcurve shape: Meteoroid density: Spectroscopy: Age: Alternative name:

Brief history: Shower has a compact core in the radiant distribution. First described by [1] from a cluster of low-light video observations from R.A. ¼ 136.5 , Decl. ¼ þ8.9 with Vg ¼ 44.9 km/s around lo ¼ 287 . An outburst was detected at this radiant by the CMOR radar on January 9, 2015 [2]. Radiant was at R.A. ¼ 137.8 , Decl. ¼ þ8.9 with Vg ¼ 47.3 km/s around lo ¼ 289 . Confirmed from single-station video observations by [3]. Finding chart in Fig. 8.46. Although the meteoroids are sodium “free”, they do not appear to have a higher density. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409; [2] Brown P. (2016) Proc. of the International Meteor Conference 2016, Egmond, the Netherlands, 2e5 June. Eds: A. Roggemans, P. Roggemans, Mechelen: IMC, p 42e45; [3] Molau S., et al. (2016) JIMO 44, 116e119; [4] Matlovic P., et al. (2019) AA 629, A71eA90.

FIG 8.46

Finding chart.

660

Anthelion source

661

January

January 19 (lo ¼ 299 )

341 XUM d January xi Ursae Majorids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet or asteroid, toroidal shower, TJ ¼ þ3.86  0.33 Annual shower January 12e25 (lo ¼ 292 e305 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 298.5 169.6 þ32.8 218.3 þ25.9 40.8 þ0.50 0.42 0.37 0.20 þ0.26 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.45 0.221 0.850 67.2 313.6 298.5 251.8 eV 0.0249 0.0322 3.76 3.62 1.64 3.62 þ0.0004 0.0011 0.21 0.26 þ1.00 þ0.74 w0.4/h (N ¼ 491, hr ¼ 63.8 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.95  0.06 (s ¼ 2.17  0.03) Component III has low He, and high F: IIa: Hb ¼ 103.4  2.26 Mv; Hmax ¼ 94.1  0.93 Mv; He ¼ 84.2 þ 1.24 Mv (N ¼ 35) III: Hb ¼ 94.0  0.97 Mv; Hmax ¼ 87.0 þ 1.12 Mv; He ¼ 82.6 þ 1.54 Mv (N ¼ 178) III: F ¼ 0.61, rather than typical F w 0.50 for type III IIa: r w 3.1 g/cm3 (a1 ¼ 0.179 km, a2 ¼ 2.17/s) III: r w 3.5 g/cm3 (a1 ¼ 0.045 km, a2 ¼ 8.25/s) dNa free Mg1.66 Fe0.75 Na0.003 (N ¼ 1), Na depleted From c: 24,000 y e

Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source:

Brief history: Strong and compact shower at an unusual radiant position near the toroidal ring. Short semi-major axis (asteroidal) orbit with high Tisserand parameter TJ ¼ þ3.86. Shower first detected from 12 orbits measured by the SonotaCo network during 2007e2008 by [1] from R.A. ¼ 169.0 , Decl. ¼ þ33.0 and Vg ¼ 40.2 km/s around lo ¼ 300.6. Confirmed from single-station data of the IMO Video Meteor Network by [2], but at higher Vg ¼ 44.2 km/s. Confirmed from triangulated data by [3]. Activity curve in Fig. 8.47. Name and number by [1]. References: [1] Kanamori T. (2009) JIMO 37, 55e62; [2] Molau S., Kac J., Berko E., Crivello S., Stomeo E., Igaz A., Barentsen G., Goncalves R. (2013) JIMO 41, 61e66; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354. FIG 8.47

ZHR profile.

662

Anthelion source

January

663

January 22 (lo ¼ 302 )

515 OLE d omicron Leonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, possible part of Phaethon Complex, TJ ¼ þ2.97  0.49 Annual shower January 10eFebruary 3 (lo ¼ 289 e315 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 302.4 150.4 þ4.9 208.3 6.7 39.6 þ0.92 0.31 0.03 þ0.02 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.00 0.088 0.956 22.1 150.1 122.4 271.6 eV 0.0391 0.0195 5.62 7.12 6.48 7.12 þ0.0000 þ0.0001 þ0.06 0.02 þ1.00 þ0.98 w0.2/h (N ¼ 592, hr ¼ 47.6 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.39  0.04 (s ¼ 1.95  0.02) Component IIa has low He, ke < 79, like III: IIa: Hb ¼ 101.2  0.49 Mv; Hmax ¼ 91.5 þ 1.43 Mv; He ¼ 85.6 þ 2.00 Mv (N ¼ 121) III: Hb ¼ 94.0  0.33 Mv; Hmax ¼ 88.6 þ 1.10 Mv; He ¼ 84.0 þ 1.42 Mv (N ¼ 199) IIa: r w 1.12  0.36 g/cm3 (a1 ¼ 0.039 km, a2 ¼ 6.45/s) III: r w 2.3  1.1 g/cm3 (a1 ¼ 0.049 km, a2 ¼ 8.38/s) dpossibly Na free From c: 8000 y e

Meteoroid density: Age: Source:

Brief history: Shower first identified from Croatian Meteor Network and SonotaCo data by [1], with 38 meteors from R.A. ¼ 144  4 , Decl. ¼ þ7  3 with speed Vg ¼ 41.5  3.8 km/s during lo ¼ 281 e308 , centered on lo ¼ 296 . Confirmed here, and identified as possibly part of Phaethon Complex. Name and number by [1]. References: [1] Segon D., et al. (2013) JIMO 41, 70e74. January 13 (lo ¼ 293 )

1168 DCN d delta1 Canis Minorids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.71  0.09 Annual shower with episodic outbursts 2015, 2020 January 2e23 (lo ¼ 282 e303 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 293.2 110.6 0.1 179.0 22.0 23.6 þ0.56 0.45 0.33 0.37 0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.83 0.622 0.780 16.1 80.5 113.2 194.0 eV 0.0120 0.0369 0.77 1.50 5.19 1.50 þ0.0062 0.0016 þ0.11 0.77 þ1.00 þ0.23 w0.03/h (N ¼ 132, hr ¼ 48.2 , m(Mv ¼ 0) ¼ 0.26 g) c ¼ 2.64  0.25 (s ¼ 2.05  0.11) Component IIa has low He, Ke < 79, like III: IIa: Hb ¼ 95.0  1.68 Mv; Hmax ¼ 84.3 þ 0.77 Mv; He ¼ 77.2 þ 2.43 Mv (N ¼ 55) IIa: r w 2.6  1.1 g/cm3 (a1 ¼ 0.039 km, a2 ¼ 4.43/s) dpossibly Na free e e

Meteoroid density: Age: Source:

Brief history: First reported from a CAMS video detection here.

664

Anthelion source

February

665

February 22 (lo ¼ 334 )

749 NMV d Northern March gamma Virginids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, possible part of Phaethon Complex, TJ ¼ þ2.92  0.37 Annual shower February 8eMarch 9 (lo ¼ 320 e348 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 334.3 184.4 þ3.6 208.5 þ5.0 40.3 þ0.66 0.38 0.24 0.08 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.03 0.077 0.964 17.7 331.8 334.3 306.2 eV 0.0231 0.0169 8.41 4.46 6.73 4.46 þ0.0024 0.0010 0.60 0.46 þ1.00 þ0.54 w0.3/h (N ¼ 714, hr ¼ 45.0 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.98  0.20 (s ¼ 2.19  0.08) High IIb/IIa ratio may point to heating from low q: IIa: Hb ¼ 100.3  0.12 Mv; Hmax ¼ 90.6 þ 1.90 Mv; He ¼ 85.7 þ 1.94 Mv (N ¼ 149) III: Hb ¼ 93.4  0.06 Mv; Hmax ¼ 88.4 þ 0.90 Mv; He ¼ 83.9 þ 1.06 Mv (N ¼ 256) IIa: r w 1.3  0.9 g/cm3 (a1 ¼ 0.116 km, a2 ¼ 4.77/s) dpossibly Na poor III: r w 1.8  1.0 g/cm3 (a1 ¼ 0.079 km, a2 ¼ 7.63/s) dpossibly Na free From c: 8600 y 323P/SOHO duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.58 0.039 0.985 5.4 353.2 324.2 317.4

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2021-Feb-12.0 TDB

Brief history: Shower is among those with the lowest perihelion distances and may be more than one shower. First described from CAMS and SonotaCo low-light video observations by [1] with R.A. ¼ 189.1 , Decl. ¼ þ3.0 and Vg ¼ 42.7 km/s around lo ¼ 339.0 . Possible parent body identified here. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409. February 15 (lo ¼ 327 )

750 SMV d Southern March gamma Virginids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, possible part of Phaethon Complex, TJ ¼ þ2.82  0.42 Annual shower February 1eMarch 8 (lo ¼ 312 e347 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 326.6 172.3 3.0 207.9 6.0 40.2 þ0.97 0.40 þ0.05 þ0.01 0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.12 0.085 0.962 20.2 150.4 146.6 296.8 eV 0.0355 0.0210 7.05 7.08 10.74 7.08 0.0005 0.0001 0.01 þ0.12 þ1.00 þ1.12 w0.4/h (N ¼ 1267, hr ¼ 43.0 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 3.10  0.28 (s ¼ 2.23  0.10) Component IIb has low He, ke < 79, like III: IIa: Hb ¼ 102.0  0.42 Mv; Hmax ¼ 92.8 þ 1.33 Mv; He ¼ 87.1 þ 1.87 Mv (N ¼ 236) IIb: Hb ¼ 94.6  0.31 Mv; Hmax ¼ 88.8 þ 0.96 Mv; He ¼ 84.3 þ 1.25 Mv (N ¼ 508) IIa: r w 1.3 g/cm3 (a1 ¼ 0.091 km, a2 ¼ 4.21/s)dpossibly Na poor IIb: r w 2.0  0.8 g/cm3 (a1 ¼ 0.043 km, a2 ¼ 8.35/s)dpossibly Na free From c: 10,000 y 323P/SOHO duncertain (see #749)

Meteoroid density: Age: Source:

Brief history: Shower is among those with the lowest perihelion distances and may be more than one shower. First described from CAMS and SonotaCo low-light video observations by [1] with R.A. ¼ 188.1 , Decl. ¼ 8.8 and Vg ¼ 40.8 km/s around lo ¼ 344.0 . Possible parent body here. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

666

Anthelion source

February

667

February 2 (lo ¼ 313 )

110 AAN d alpha Antliids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type comet, toroidal, sunskirter, TJ ¼ þ1.76  0.51 Annual shower January 20eFebruary 19 (lo ¼ 300 e330 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 313.2 158.7 10.2 210.8 17.5 44.3 þ0.75 0.36 0.14 0.05 0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.54 0.141 0.960 57.6 138.6 133.2 272.0 eV 0.0217 0.0223 5.26 3.58 11.99 3.58 þ0.0015 0.0006 0.35 0.24 þ1.00 þ0.76 w0.23/h (N ¼ 635, hr ¼ 44.1 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 5.55  0.38 (s ¼ 2.86  0.07) Predominantly deeply penetrating component IIb: Ib: Hb ¼ 105.3  1.40 Mv; Hmax ¼ 96.5 þ 0.18 Mv; He ¼ 91.2 þ 0.20 Mv (N ¼ 49) IIb: Hb ¼ 95.9  0.65 Mv; Hmax ¼ 90.9 þ 0.16 Mv; He ¼ 85.5 þ 0.62 Mv (N ¼ 456) Ib: r w 1.3 g/cm3 (a1 ¼ 0.034 km, a2 ¼ 6.79/s) IIb: r w 2.3  0.8 g/cm3 (a1 ¼ 0.035 km, a2 ¼ 9.72/s) dpossibly Na poor/free From c and s: w19,000 y e

Meteoroid density: Age: Source:

Brief history: Strong shower in video and in radar. Follows the a-Hydrids (#331) after lo ¼ 305 , but located at a different latitude. First reported by [1] from AMOR radar data with 327 meteors radiating from R.A. ¼ 162.1 , Decl. ¼ 13.3 and Vg ¼ 42.7 km/s around lo ¼ 313.1 (“Peak 1”). That detection was confirmed by [2] from CMOR radar observations (called “alpha Antilids”), giving a range lo ¼ 308 e321 . Shower is rich in faint meteors. In IMO Video Meteor Network single-station video data, [3] detected a weak shower at R.A. ¼ 162 , Decl. ¼ 14 and Vg ¼ 45 km/s. [4] confirmed the shower from triangulated video data. Before that, visual observers of the International Meteor Organization reported “a-Hydrids” with R.A. ¼ 140.0 , Decl. ¼ 10.0 around lo ¼ 304.7 , which includes perhaps this shower. Name by [1], number by [5]. References: [1] Galligan D. P., Baggaley W. J. (2002) In: Dust in the Solar System and Other Planetary Systems. Eds: S. F. Green, I. P. Williams, J. A. M. McDonnell, N. McBride. New York: Pergamon, pp. 48e60; [2] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [3] Molau S., Kac J. (2009) JIMO 37, 75e76; [4] Jenniskens P., et al. (2016) Icarus 266, 331e354; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 696.

668

Anthelion source

February

669

February 24 (lo ¼ 337 )

732 FGV d February gamma Virginids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2021-Feb-11.0 TDB

Jupiter-family comet/asteroid, sunskirter, TJ ¼ þ3.70  0.58 (increase with lo) Annual shower February 19e28 (lo ¼ 332 e340 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 337.0 190.8 2.8 213.9 þ1.7 41.2 þ0.66 þ0.36 0.26 0.07 þ0.21 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.49 0.030 0.980 9.8 343.7 337.0 320.9 eV 0.0076 0.007 3.13 1.85 1.86 1.85 þ0.0002 þ0.0006 0.39 0.18 þ1.00 þ0.82 w0.4/h (N ¼ 99, hr ¼ 47.4 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 4.07  0.13 (s ¼ 2.52  0.04) III: Hb ¼ 92.4  0.06 Mv; Hmax ¼ 88.6 þ 0.29 Mv; He ¼ 84.5 þ 0.30 Mv (N ¼ 81) III: r w 1.8  0.7 g/cm3 (a1 ¼ 0.063 km, a2 ¼ 10.17 /s) dpossibly Na poor/free From c: 4600 y 323P/SOHO a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.58 0.039 0.985 5.37 353.2 324.2 317.4

Brief history: First identified by [1] from CAMS, SonotaCo, CMN, and EDMOND video data from R.A. ¼ 191.1 , Decl. ¼ 3.0 and Vg ¼ 41.2 km/s around lo ¼ 338 . 323P source identified here. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

670

Anthelion source

171 ARIdDaytime Arietids

C H A P T E R

9

Helion source

Atlas of Earth's Meteor Showers https://doi.org/10.1016/B978-0-323-88447-1.00002-8

671

© 2024 Elsevier Inc. All rights reserved.

672

Helion source

673

March

March 8 (lo ¼ 348 )

128 MKA d Daytime kappa Aquariids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB Source: Epoch 2007-Jun-04.0 TDB

Jupiter-family comet or asteroid, TJ ¼ þ4.79  0.36 Annual or episodic shower -.March 3e12 (lo ¼ 343e351 ) R.A. ( ) Decl. ( ) l ( ) b ( ) lo ( ) 347.7 326.7 10.1 339.3 þ2.8 þ0.89 0.41 þ0.11 0.05 a (AU) q (AU) e i ( ) u ( ) 1.23 0.244 0.803 4.3 46.0 0.024 0.025 1.9 3.0 þ0.0010 þ0.0001 0.07 þ0.17 N ¼ 401 (m(Mv ¼ 0) ¼ 0.19 g) -.r w 0.7e3.5 g/cm3 -.2002 EV11 a (AU) q (AU) e i ( ) u ( ) 2.34 0.317 0.864 5.55 115.3 2007 KG7 1.78 0.237 0.867 4.74 318.3

eR

Vg (km/s) 27.3 þ0.01 U ( ) 347.7 3.2 þ1.00

P ( ) 33.1 4.0 þ1.17

U ( ) 108.4

P ( ) 223.7

66.3

24.6

e R[S]

Brief history: First detected from three orbits measured by the radar of the University of Adelaide, Australia, during March 12e16, 1961 [1]. Shower was again detected from 10 meteors in 1968e1969 season [2]. Average radiant was at R.A. ¼ 338 , Decl. ¼ 8 . Proposed daytime twin of Northern i-Aquariids [2]. Confirmed by Canadian Meteor Orbit Radar (CMOR) during March 6 to 10 (lo ¼ 346e350 ) [3]. Activity may be episodic, as it was not seen in AMOR data (Fig. 9.1). A compact group was detected by SAAMER from R.A. ¼ 326.8 , Decl. ¼ 9.3 and Vg ¼ 26.5  1.2 km/s during lo ¼ 349.1e350.3 (N ¼ 6, in 2018 and 2020). Yearly number detected by SAAMER starting in 2017: 34, 113, 137, 117. Peak activity on March 10 (lo ¼ 350 ) from radiant at R.A. ¼ 332 , Decl. ¼ 8.4 . Geocentric velocity Vg ¼ 31.4 km/s. Semi-major axis likely as small as measured here. Proposed parent body: 2002 EV11 by [4] and 2007 KG7 by [3]. Name and number by [5]. References: [1] Nilsson C. S. (1964) AuJPh 17, 226e229; [2] Gatrell G., Elford W. G. (1975) AuJPh 28, 596e603; [3] Brown P., Wong D. K., Weryk R. J., Wiegert P. (2010) Icarus 207, 66e81; [4] Ye Q.-Z. (2018) PSS 164, 7e12; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 701. FIG 9.1 Shower MKA not detected by AMOR (partial sky coverage).

674

Helion source

675

April

April 19 (lo ¼ 29 )

144 APS d Daytime April Piscids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

Jupiter-family comet or asteroid, TJ ¼ þ4.70  0.75 Annual shower April 5eMay 6 (lo ¼ 15e46 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 29.3 4.9 þ5.5 341.9 þ3.3 þ1.01 0.45 þ0.09 þ0.02 a (AU) q (AU) e i ( ) u ( ) 1.10 0.253 0.771 4.4 50.5 0.0439 0.0529 1.41 4.92 þ0.0006 0.002 þ0.03 þ0.10 1.51 0.256 0.831 4.7 50.1 N ¼ 3900 (m(Mv ¼ 0) ¼ 0.22 g) -.r w 0.7e3.5 g/cm3 -.(242643) 2005 NZ6 a (AU) q (AU) e i ( ) u ( ) 1.83 0.247 0.865 8.42 49.0

eR

Vg (km/s) 25.7 þ0.01 U ( ) 29.3 6.80 þ1.00 24.7

P ( ) 78.8 4.92 þ1.10 74.8

U ( ) 38.8

P ( ) 87.8

e R[S] e R[4]

Brief history: First mentioned by [1] from 3 meteors detected by the Adelaide radar from R.A. ¼ 6.5 , Decl. ¼ þ4.3 and Vg ¼ 25.1 km/s during April 13e29 (Shower 61.4.2). Confirmed by [2] from 34 meteors detected by the Kharkov Polytechnical Institute radar from R.A. ¼ 7 , Decl. ¼ þ3 with Vg ¼ 31 km/s and centered on lo ¼ 30 . [4] gives Vg ¼ 28.9  3.4 km/s and duration range lo ¼ 16e33 . Semi-major axis likely as small as measured here. Source identified by [4] as possibly the low albedo (0.041) and slow rotating (10 h) 1.99-km sized minor planet 2005 NZ6. Possibly associated with the Iota Aquariids [4]. Name and number assigned by [3]. References: [1] Nilsson C. S. (1964) AuJPh 17, 205e256; [2] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [4] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339. April 4 (lo ¼ 14 )

1207 OMP d omicron Piscids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, TJ ¼ þ4.19  0.48 Annual shower April 3e12 (lo ¼ 13e22 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 14.4 28.4 þ7.7 341.2 5.0 þ0.87 þ0.37 0.06 0.00 a (AU) q (AU) e i ( ) u ( ) 1.24 0.285 0.774 5.7 229.6 0.0428 0.0484 3.82 5.04 0.0009 þ0.0003 þ0.01 0.14 N ¼ 2893 (m(Mv ¼ 0) ¼ 0.21 g) -.r w 0.7e3.5 g/cm3 -.-.-

eR

Vg (km/s) 25.9 þ0.01 U ( ) 194.4 3.20 þ1.00

P ( ) 64.9 5.04 þ0.86

e R[S]

Brief history: Identified from SAAMER-OS radar data by [1] in this work. Semi-major axis likely as small as measured here. Name and number assigned here. References: [1] Bruzzone J. S., et al. (2020) PSS 188, article id. 104936.

676

Helion source

677

May

May 5 (lo ¼ 45 )

156 SMA d Southern Daytime May Arietids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, TJ ¼ þ3.73  0.77 Annual shower April 11eMay 25 (lo ¼ 21e65 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 44.9 27.1 þ6.3 344.3 4.4 þ0.92 þ0.34 0.31 0.01 a (AU) q (AU) e i ( ) u ( ) 1.37 0.325 0.768 4.6 235.2 0.0476 0.0530 1.90 5.75 0.0003 0.000 0.01 0.07 1.51 0.272 0.820 5.1 231.7 N ¼ 10,276 (m(Mv ¼ 0) ¼ 0.22 g) -.r w 0.7e3.5 g/cm3 -.-.-

eR

Vg (km/s) 25.6 þ0.00 U ( ) 224.9 10.81 þ1.00 227.1

P ( ) 99.1 5.75 þ0.94 98.8

e R[S] e R[1]

Brief history: Shower first reported from 1961 Adelaide radar data by [1] from R.A. ¼ 40.6 , Decl. ¼ þ5.6 (B1950.0) and Vg ¼ 31.3 km/s around lo ¼ 64.0 (shower 61.5.6) at the end of the activity period. Kharkiv radar [2] had radiant at R.A. ¼ 33.7 , Decl. ¼ þ9.2 and Vg ¼ 28.9 km/s around lo ¼ 52.7 . Also observed by CMOR radar [3] from R.A. ¼ 28.4 , Decl. ¼ þ7.7 and Vg ¼ 28.3 km/s around lo ¼ 47.1 . Number and name assigned by [4]. References: [1] Nilsson C. S. (1964) AuJPh 17, 205e256; [2] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [3] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp.

May 16 (lo ¼ 56 )

155 NMA d Northern Daytime May Arietids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter family comet, TJ ¼ þ3.21  0.77 Annual shower April 26eMay 31 (lo ¼ 36e71 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 55.8 38.0 þ18.7 347.0 þ0.83 þ0.27 0.18 a (AU) q (AU) e i ( ) 1.56 0.353 0.777 4.3 0.0415 0.0472 1.38 0.0025 þ0.0002 þ0.04 1.53 0.33 0.785 3.4 N ¼ 1789 (m(Mv ¼ 0) ¼ 0.22 g) -.r w 0.7e3.5 g/cm3 -.-.-

eR b ( ) þ3.5 þ0.01 u ( ) 60.4 5.29 0.37 60.8

Vg (km/s) 25.8 þ0.03 U ( ) 55.8 8.39 þ1.00 55.0

P ( ) 115.3 5.29 þ0.64 115.8

e R[S] e R[2]

Brief history: Shower first reported from Adelaide radar data by [1] at R.A. ¼ 46.5 , Decl. ¼ þ19.8 (B1950.0) and Vg ¼ 26.4 km/s around lo ¼ 62.1 (shower 61.5.2). Confirmed by [2] (shower 10), while [3] reported 56 Harvard Meteor Project radar orbits from R.A. ¼ 37.2 , Decl. ¼ þ18.1 and Vg ¼ 25.2 km/s around lo ¼ 55.0 . Number and name assigned by [4]. Stands out from shower 144 in ecliptic longitude versus solar longitude diagram. References: [1] Nilsson C. S. (1964) AuJPh 17, 205e256; [2] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [3] Sekanina Z. (1976) Icarus 27, 265e321; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp.

678

Helion source

679

May

May 7 (lo ¼ 48 )

143 LPE e Daytime lambda Pegasids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter family comet or asteroid, sunskirter, TJ ¼ +5.38  0.74 Annual shower April 29 e May 15 (lo ¼ 38 e 55 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 47.6 4.3 +20.7 325.5 +17.9 33.7 +0.47 +0.31 -0.45 +0.10 -0.16 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.07 0.131 0.873 43.3 31.4 47.6 78.3 eV 0.0141 0.0184 2.90 1.77 6.32 1.77 -0.0012 -0.0015 +0.33 -0.47 +1.00 +0.53 w0.01 /h (N ¼ 10, hr ¼ 21.5 , m(Mv¼0) ¼ 0.12 g) c ¼ 3.08  0.43 (s ¼ 2.22  0.16) IIa: Hb ¼ 100.5 - 1.93 Mv; Hmax ¼ 85.5 + 2.40 Mv; He ¼ 81.9 + 2.44 Mv (N ¼ 8) IIa: r w 2.3 g/cm3 (a1 ¼ 0.0975 km, a2 ¼ 3.78 /s) e uncertain due to low N

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

April 21 e May 20 (lo ¼ 30 e 60 ) lo ( ) R.A. ( ) Decl. ( ) 45.2 1.8 +21.8 +0.95 +0.33 a (AU) q (AU) e 1.03 0.155 0.850 0.0265 0.0450 -0.0014 +0.0026 1.42 0.21 0.785 N ¼ 323

l ( ) 325.5 -0.01 i ( ) 43.5 8.89 +0.38 61.0

b ( ) +19.3 -0.07 u ( ) 32.3 4.18 -0.01 44.0

Vg (km/s) 33.4 +0.20 U ( ) 45.3 8.66 +1.00 29.7

P ( ) 78.1 4.18 +0.99 73.7

e R[M] e R[1]

Brief history: Detected in MAARSY data. Shower perhaps first reported from Kharkiv radar data by [1] from R.A. ¼ 343.5 , Decl. ¼ +19.9 (B1950.0) and Vg ¼ 38.4 km/s around lo ¼ 29.7 , corresponding to R.A. ¼ 358.2 , Decl. ¼ +26.9 around lo ¼ 45.2 , a few degrees above the observed position. Detection in CAMS video data reported here. Name and number by [2]. Fig. 9.2 shows same period of time in AMOR radar data.. References: [1] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp. FIG 9.2

Detection of shower #153 by AMOR, which has partial sky coverage.

680

Helion source

681

June

June 11 (lo ¼ 81 )

325 DLT d Daytime lambda Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter family comet, sunskirter, TJ ¼ þ2.31  0.27 Annual shower May 21eJune 18 (lo ¼ 61 e89 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 81.4 51.4 þ11.5 331.7 6.9 40.6 þ0.87 þ0.38 0.07 þ0.13 þ0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.61 0.083 0.969 27.1 209.4 261.4 106.5 eV 0.0295 0.0188 9.48 5.32 9.01 5.32 0.0015 þ0.0005 0.19 0.31 þ1.00 þ0.69 w0.7/h (N ¼ 35, hr ¼ 12.7 , m(Mv ¼ 0) ¼ 0.07 g) 3.97  0.28 (s ¼ 2.50  0.08) Component II has high end height, Ke > 82: II: Hb ¼ 100.2 þ 0.02 Mv; Hmax ¼ 94.9 þ 1.18 Mv; He ¼ 89.9 þ 1.77 Mv (N ¼ 34) II: low F ¼ 0.51, fragile IIa: r  3.0 g/cm3 (a1 ¼ 0.142 km, a2 ¼ 2.68/s) duncertain due to low N

Lightcurve shape: Meteoroid density:

Period of activity: May 21eJune 18 (lo ¼ 79 e95 ) R.A. ( ) Decl. ( ) Shower radiant/speed lo ( ) Median (geocentric): 86.0 59.2 þ14.0 Drift per day (d/dlo): þ0.94 þ0.29 Orbital elements (J2000.0) a (AU) q (AU) e Median: 1.92 0.112 0.942 Dispersion (±s): 0.0438 0.0326 Drift (d/dlo): 0.0015 þ0.0013 Median: 1.57 0.104 0.934 Number observed: N ¼ 210

l ( ) 333.8 0.05 i ( ) 16.9 6.76 0.23 23.2

b ( ) 6.1 þ0.11 u ( ) 212.2 7.33 0.17 210.8

Vg (km/s) 37.0 þ0.09 U ( ) 265.6 3.77 þ1.00 265.5

96P captured by Jupiter: w20000 y [4]; Formation Marsden group 1100e1900 y [4]; mostly 96P 10000e20000 y [4]; 3000e5000 y [2] From c: 12,000 y Source: 96P/Machholz 1 Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) Epoch 2008-Nov-03.0 TDB 3.03 0.123 0.959 58.5 14.7 94.4 Source: C/1733 K1 Epoch 1864-Jul-28.0 TDB N 0.103 1.000 23.8 187.9 271.1

P ( ) 118.8 7.95 þ0.83 116.3

e R[M] e R[1]

Age:

P ( ) 109.1 duncertain 99.0

Brief history: Part of Machholz Complex. Strong shower in CMOR radar observations [1] from wavelet analysis with R.A. ¼ 56.7  0.8 , Decl. ¼ þ11.5  0.3 and Vg ¼ 36.4  3.7 km/ s around lo ¼ 85.5 . Node reported incorrectly by [1]. Weak detection in video reported here. Identified here as “Filament 4” from 96P ejecta in [2], with R.A. ¼ 49.9  3.4 , Decl. ¼ þ13.1  1.6 and Vg ¼ 38.6 km/s during May 26eJune 15. C/1733 K1 proposed as an alternative source by [3]. Name and number by [1]. References: [1] Brown P., et al. (2008) Icarus 195, 317e339; [2] Neslusan L., Hajduková M., Jakubík M. (2015) AA 560, A47eA57; [3] Brown P., et al. (2010) Icarus 207, 68e81; [4] Abedin A., et al. (2018) Icarus 300, 360e385.

682

Helion source

683

June

June 20 (lo ¼ 90 )

324 EPR d epsilon Perseids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Mellish-type shower, toroidal, TJ ¼ þ0.88  0.39 Annual shower June 6e30 (lo ¼ 76 e106 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 90.1 54.9 þ37.4 331.3 þ17.3 44.3 þ0.96 þ0.17 0.18 0.01 þ0.14 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.67 0.151 0.982 56.0 44.7 90.0 134.5 0.0243 0.0184 5.15 3.93 6.41 3.93 0.0015 þ0.0004 þ0.60 0.22 þ1.00 þ0.78 w0.4/h (N ¼ 112, hr ¼ 18.7 , m(Mv ¼ 0) ¼ 0.06 g) 2.57  0.25 (s ¼ 2.03  0.10) Component IIa has high end height, Ke > 82 due to shallow entry angle: IIa: Hb ¼ 102.41.02 Mv; Hmax ¼ 96.2 þ 0.33 Mv; He ¼ 91.6 þ 0.71 Mv (N ¼ 80) IIa: r w 3.9 g/cm3 (a1 ¼ 0.038 km, a2 ¼ 3.52/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

June 12eJuly 2 (lo ¼ 80 e100 ) lo ( ) R.A. ( ) Decl. ( ) 91.1 51.9 þ38.1 þ1.03 þ0.29 a (AU) q (AU) e 2.50 0.150 0.943 0.0249 0.0330 þ0.0005 0.0013 4.55 0.130 0.971 N ¼ 186

b ( ) þ18.6 þ0.07 u ( ) 41.0 4.50 0.02 39.7

Vg (km/s) 42.2 0.09 U ( ) 91.1 5.18 þ1.00 96.0

Age: Source: Orbital elements (J2000.0) Epoch 2008-Mar-20.0 TDB

From c and s: w6200 y Meyer group of sunskirting comets, e.g., C/2008 F1 a (AU) q (AU) e i ( ) u ( ) N 0.032 (1.000) 66.7 46.1

U ( ) 94.6

l ( ) 328.7 0.09 i ( ) 58.4 6.99 þ0.01 63.0

P ( ) 131.9 4.50 þ0.98 135.7

eV

e R[M] e R[1]

duncertain P ( ) 140.7

Brief history: First identified in 2002e2006 CMOR radar observations by [1] from R.A. ¼ 58.2 , Decl. ¼ þ37.9 and Vg ¼ 44.8 km/s around lo ¼ 95.5 . Activity period lo ¼ 92e107 . Not known by visual observers. The IMO Video Meteor Network detected this shower only on lo ¼ 94.0 from 1993e2012 single-station meteor tracks, when 27 meteors appeared to radiate from R.A. ¼ 60.8 , Decl. ¼ þ41.5 [2]. Confirmed from CAMS video triangulations by [3]. Activity curve shown in Fig. 9.3. Number and name by [1].

FIG 9.3

ZHR profile (scale uncertain).

References: [1] Brown P., et al. (2008) Icarus 195, 317e339; [2] Kronk G. W. (2014) Meteor Showers, An Annotated Catalog, 2nd ed., New York: Springer, p. 117e121; [3] Jenniskens P., et al. (2016) Icarus 266, 355e370.

684

Helion source

685

July

July 7 (lo ¼ 105 )

369 JTR d July Taurids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, sunskirter, TJ ¼ þ4.50  0.72 Annual shower July 2e14 (lo ¼ 100 e112 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 105.0 70.7 þ2.2 324.8 19.9 36.6 þ0.84 þ0.14 0.11 þ0.02 þ0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) 1.23 0.148 0.881 52.5 214.6 285.0 0.0135 0.0248 6.43 2.28 2.97 0.0011 þ0.0014 þ0.48 0.09 þ1.00 1.54 0.155 0.900 60.9 217.8 284.0 N ¼ 188 (m(Mv ¼ 0) ¼ 0.09 g) -.r w 0.7e3.5 g/cm3 -.-.-

eR

P ( ) 139.5 2.28 þ0.91 141.8

e R[S] e R[1]

Brief history: First reported from CMOR radar data by [1] from R.A. ¼ 70.0 , Decl. ¼ þ1.5 and Vg ¼ 39.7 km/s around lo ¼ 104.0 . Semi-major axis may be higher than measured here. Name and number by [1]. References: [1] Brown P., Wong D. K., Weryk R J., Wiegert P. (2010) Icarus 207, 66e81. July 16 (lo ¼ 116 )

1210 GAG d gamma Geminids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2015-Oct-01.0 TDB

Jupiter-family comet, TJ ¼ þ4.30  0.81 Annual shower June 30eAugust 16 (lo ¼ 99 e144 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 115.8 99.3 þ14.9 342.7 þ1.58 0.14 þ0.54 a (AU) q (AU) e i ( ) 1.47 0.302 0.810 8.25 0.126 0.124 6.83 þ0.0094 0.0055 0.25 N ¼ 8120 (m(Mv ¼ 0) ¼ 0.19 g) -.r w 0.7e3.5 g/cm3 -.2P/Encke a (AU) q (AU) e i ( ) 2.22 0.336 0.848 11.8

eR b ( ) 7.2 0.02 u ( ) 233.4 15.3 þ1.10

Vg (km/s) 27.4 0.28 U ( ) 295.8 10.2 þ1.00

P ( ) 169.4 15.3 þ2.10

u ( ) 186.5

U ( ) 334.6

P ( ) 161.1

e R[S]

Brief history: First identified here from strong asymmetry in helion source in SAAMER data described by [1]. Shower velocity is lower than that of shower #1211. References: [1] Bruzzone J. S., et al. (2020) PSS 188, article id. 104936.

686

Helion source

687

August

August 3 (lo ¼ 131 )

188 XRI e Daytime xi Orionids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, sunskirter, TJ ¼ +1.00  1.03 Annual shower July 25 e August 23 (lo ¼ 122 e 151 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 130.7 104.1 +15.5 331.3 -7.4 43.6 +0.73 -0.10 -0.28 -0.02 -0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.94 0.063 0.986 30.0 208.0 310.6 159.3 eV 0.0105 0.0085 4.71 2.16 9.95 2.16 -0.0014 -0.0007 +0.44 -0.44 +1.00 +0.56 w0.02 /h (N ¼ 11, hr ¼ 10.3 , m(Mv¼0) ¼ 0.06 g) c ¼ 3.45  0.89 (s ¼ 2.34  0.27) IIa: Hb ¼ 103.4 - 1.37 Mv; Hmax ¼ 96.3 + 0.20 Mv; He ¼ 90.4 + 0.81 Mv (N ¼ 9) e uncertain due to low N IIa: r w 3.5 g/cm3 (a1 ¼ 0.113 km, a2 ¼ 1.87 /s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

July 24 e August 26 (lo ¼ 121 e 154 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) 136.0 103.8 +16.9 327.4 +0.91 -0.02 -0.13 a (AU) q (AU) e i ( ) 1.68 0.054 0.972 24.6 0.0671 0.0396 11.5 -0.0009 +0.0004 +0.00 8.33 0.080 0.990 32.8 N ¼ 153

Age: Source:

-.-.-

b ( ) -5.7 +0.07 u ( ) 202.0 3.69 -0.21 211.6

Vg (km/s) 40.0 +0.03 U ( ) 316.0 8.66 +1.00 301.9

P ( ) 157.0 3.69 +0.78 153.5

e R[M] e R[1]

Brief history: First reported from Adelaide radar observations by [1] based on three meteors radiating from R.A. ¼ 94.4 , Decl. ¼ +15.0 and Vg ¼ 44.0 km/s around lo ¼ 121.9 . Confirmed by [2] from CMOR data with Vg ¼ 45.4 km/s, who noticed a more extended period of activity and put the peak activity at lo ¼ 131.5 . These CMOR observations combine showers #188 and #1211, here separated. Detection from CAMS low-light video observations reported here. Name and number by [3]. References: [1] Nilsson C. S. (1964) AuJPh 17, 226e229; [2] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp.

August 12 (lo ¼ 140 )

1211 SFG d 74 Geminids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Meteoroid density:

Jupiter-family comet, sunskirter, TJ ¼ þ1.98  1.52 Annual shower July 24eAugust 27 (lo ¼ 121 e155 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 139.7 115.9 þ16.0 335.1 5.2 þ0.89 0.17 0.12 0.03 a (AU) q (AU) e i ( ) u ( ) 2.66 0.116 0.968 14.8 216.2 0.0524 0.0539 7.30 7.01 0.0012 þ0.0004 þ0.21 0.19 N ¼ 410 (m(Mv ¼ 0) ¼ 0.08 g) r w 0.7e3.5 g/cm3

eR

Vg (km/s) 39.5 þ0.07 U ( ) 319.7 3.56 þ1.00

P ( ) 175.5 7.01 þ0.81

e R[M]

Brief history: Higher-ecliptic longitude component of original shower #188, which was found here to be split in two components in MU Radar [1], MAARSY [2], and SAAMER data [3]. Perhaps first detected by [4] from 23 Kharkiv radar detected meteors, but with lower mean velocity Vg ¼ 38.4 km/s. References: [1] Kero J., et al. (2012) MNRAS 425, 135e146; [2] Schult C., Kero J., Stober G., Brown P. (2021) Icarus 355, id. 114137; [3] Bruzzone J. S., et al. (2020) PSS 188, article id. 104936; [4] Kashcheyev B. L., Lebedinets V. N. (1967) SCoA 7, 183e199.

688

Helion source

689

August

August 27 (lo ¼ 154 )

426 DCR d Daytime Craterids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1994-Feb 17.0 TDB

Mellish type shower or Jupiter-family comet, TJ ¼ þ3.32  0.77 Episodic shower 2002 (CMOR), 2008 (CMOR), 2018 (SAAMER) June 30eJuly 25 (lo ¼ 140 e159 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 154.0 165.8 15.9 20.3 20.2 15.1 þ0.52 þ0.02 0.55 þ0.22 þ0.20 a (AU) q (AU) e i ( ) u ( ) U ( ) 2.23 0.851 0.624 8.46 306.4 334.0 0.0265 0.137 1.84 4.37 4.42 0.0047 þ0.0055 þ0.04 0.70 þ1.00 4.07 0.805 0.802 9.7 303.0 338.0 N ¼ 515 (m(Mv ¼ 0) ¼ 0.65 g) -.r w 0.4e2.8 g/cm3 -.C/2007 W1 (Boattini) a (AU) q (AU) e i ( ) u ( ) U ( ) Inf. 0.850 1.0002 9.89 306.5 334.5

eR

P ( ) 279.5 4.37 þ0.30 281.0

e R[S] e R[1]

duncertain P ( ) 281.0

Brief history: Shower first reported from 2002 CMOR observations by [1] from R.A. ¼ 168.8 , Decl. ¼ 15.3 and Vg ¼ 18.9 km/s around lo ¼ 158.1 . Shower is completely absent in nonoutburst years (e.g., Fig. 9.4), but is active over many days in outburst years. The orbit passes close to Jupiter. Model by [1], who suggested the association with C/2007 W1 meaning that this comet was likely perturbed into a hyperbolic orbit during the 2007 return. Predicted a return in 2015. In 2018 SAAMER data, there may be two radiating centers at R.A. ¼ 167.3 , Decl. ¼ 15.0 and R.A. ¼ 166.5 , Decl. ¼ 17.8 , respectively. Name and number by [1]. References: [1] Wiegert P. A., Brown P. G., Weryk R. J., Wong D. K. (2011) MNRAS 414, 668e676.

FIG 9.4 Episodic shower not detected by AMOR during 1990e99 (partial sky coverage).

690

Helion source

691

August

August 23 (lo ¼ 151 ) 202 ZCA d Daytime zeta Cancrids

[map see on p. 692]

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density:

Mellish-type comet, TJ ¼ þ0.98  0.85 Annual shower August 10dSep. 8 (lo ¼ 138 e165 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 151.1 123.8 þ13.5 335.0 5.9 43.4 þ1.13 0.28 þ0.14 0.01 0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 8.31 0.084 0.989 22.6 212.7 331.1 178.6 eV 0.0191 0.0112 2.40 5.02 8.57 5.02 þ0.0016 0.0001 0.24 þ0.36 þ1.00 þ1.36 w0.08/h (N ¼ 13, hr ¼ 11.4 , m(Mv ¼ 0) ¼ 0.06 g) 2.78  0.52 (s ¼ 2.11  0.17) IIa: Hb ¼ 102.60.44 Mv; Hmax ¼ 98.90.45 Mv; He ¼ 93.3 þ 0.04 Mv (N ¼ 7) F ¼ 0.40: Fragile; meteors also have relatively high end height IIa: r  1.05 g/cm3 (a1 ¼ 1.22 km, a2 ¼ 1.02/s) duncertain due to low N

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

August 13e31 (lo ¼ 141 e156 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 147.8 124.3 þ13.3 334.8 6.2 þ0.85 0.26 0.14 0.07 a (AU) q (AU) e i ( ) u ( ) 2.46 0.117 0.956 16.5 215.1 0.0342 0.0305 5.35 5.43 0.0012 þ0.0000 þ0.30 0.24 N ¼ 969

Vg (km/s) 38.8 þ0.04 U ( ) P ( ) 327.8 183.4 3.84 5.43 þ1.00 þ0.76

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

September 1e12 (lo ¼ 158 e170 ) R.A. ( ) Decl. ( ) l ( ) b ( ) lo ( ) 164.1 138.9 þ10.8 333.3 4.9 þ0.98 0.21 þ0.01 þ0.08 a (AU) q (AU) e i ( ) u ( ) 2.55 0.087 0.969 15.3 210.9 0.0362 0.0224 8.15 7.22 þ0.0001 0.0003 0.34 þ0.02 4.64 0.088 0.981 16.6 212.6 N ¼ 1159

Vg (km/s) 40.2 0.03 U ( ) P ( ) 343.8 195.1 2.60 7.22 þ1.00 þ0.98 340.0 192.6

Age: Source:

From c and s: w4100 y -.-

e R[S]

e R[S] e R[1]

Brief history: First reported by [1] (shower 61.8.5) from Adelaide radar observations from R.A. ¼ 119.7 , Decl. ¼ þ19.0 and Vg ¼ 43.8 km/s around lo ¼ 146.9 . Confirmed by [2] from CMOR data, who found a radiant at R.A. ¼ 136.1 , Decl. ¼ þ11.7 and Vg ¼ 42.1 km/s around lo ¼ 160.0 using a hat-function algorithm. SAAMER data shows perhaps two related showers, the second component being the strongest. Weak detection in video observations reported here. Name and number by [2]. References: [1] Nilsson C. S. (1964) AuJPh 17, 226e229; [2] Brown P., et al. (2010) Icarus 207, 66e81.

692

Helion source

693

September

September 25 (lo ¼ 182 )

212 KLE d Daytime kappa Leonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Long-period comet, sunskirter, TJ ¼ þ0.54  0.22 Annual shower September 18eOct. 4 (lo ¼ 160 e191 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 182.2 160.7 þ15.6 334.6 þ7.2 45.2 þ0.57 0.29 0.38y 0.06y þ0.10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 21.3 0.075 0.997 27.4 32.2 181.4 215.3 eV 0.0197 0.0092 7.59 3.83 4.41 3.83 0.0038 0.0003 þ0.56 0.83 þ1.00 þ0.17 w1/h (N ¼ 58, hr ¼ 12.6 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 3.16  0.36 (s ¼ 2.25  0.12) Wide distribution, no clear separation. Ib has high He from shallow entry: Ib: Hb ¼ 107.4e1.12 Mv; Hmax ¼ 99.7 þ 0.68 Mv; He ¼ 96.5 þ 0.94 Mv (N ¼ 19) IIb: Hb ¼ 98.7e0.10 Mv; Hmax ¼ 95.2 þ 0.93 Mv; He ¼ 91.3 þ 0.87 Mv (N ¼ 14) Ib: r w 2.2 g/cm3 (a1 ¼ 0.466 km, a2 ¼ 1.08/s) duncertain due to low N IIb: r w 5.5 g/cm3 (a1 ¼ 0.059 km, a2 ¼ 3.46/s) dpossibly Na poor

Meteoroid density:

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

September 3eOct. 13 (lo ¼ 160 e200 ) R.A. ( ) Decl. ( ) l ( ) lo ( ) 182.1 161.4 þ17.1 334.3 þ0.66 0.30 0.30 a (AU) q (AU) e i ( ) 5.94 0.1105 0.994 27.3 0.0217 0.0139 4.22 0.0036 þ0.0002 þ0.53 (17) 0.17 0.99 24.8 N ¼ 422

Age: Source: Orbital elements (J2000.0) Epoch 2022-Jan-21.0 TDB

From c and s: w7500 y C/1917 F1 (Mellish) a (AU) q (AU) e 27.4 0.190 0.993

i ( ) 32.7

b ( ) þ8.5 0.04 u ( ) 38.1 4.31 0.66 31.9

Vg (km/s) 43.1 þ0.18 U ( ) 182.1 7.65 þ1.00 184.2

P ( ) 220.4 4.31 þ0.34 216.1

u ( ) 121.3

U ( ) 88.7

P ( ) 210.0

e R[M] e R[1]

Brief history: Possible twin shower of the December Monocerotids (#19) [3]. High percentage of type II deeply penetrating meteoroids. First detected with Adelaide radar by [1] recording 9 meteors from R.A. ¼ 162.2 , Decl. ¼ þ14.0 with Vg ¼ 44.8 km/s (shower 61.9.4). Confirmed by [2], with 21 meteors from Kharkiv Radar. Confirmed from video observations here. [4,5] identify this shower as possibly representing “Filament 2” from C/1917F1 ejecta in their model. Predicted radiant, however, is at R.A. ¼ 152.6  7.3 , Decl. ¼ þ19.6  4.5 with Vg ¼ 40.5  4.0 km/s around lo ¼ 158.6 . There is a possible more diffuse stream just NE of the radiant active mostly earlier in solar longitude. Name and number by [5]. References: [1] Nilsson C. S. (1964) AuJPh 17, 226e229; [2] Kashcheyev B. L., Lebedinets V. N. (1963) SCoA 7, 183e199; [3] Neslusan L., Hajduková M. (2014) AA 566, A33eA42; [4] Neslusan L., Vaubaillon J., Hajduková M. (2016) AA 589, A100eA110; [5] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp.

694

Helion source

September

695

696

Helion source

697

October

September 18 (lo ¼ 175 )

381 DPL d Daytime pi Leonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, sunskirter, TJ ¼ þ2.12  1.18 Annual shower September 5e27 (lo ¼ 162 e184 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 174.7 149.9 þ7.6 334.4 4.5 41.3 þ0.96 0.43 þ0.04 0.08 0.12 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.06 0.082 0.973 15.6 211.7 354.7 206.5 eV 0.0247 0.0302 6.24 3.26 6.53 3.26 þ0.0015 0.0013 þ0.09 þ0.22 þ1.00 þ1.22 w0.3/h (N ¼ 17, hr ¼ 11.9 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 3.18  0.64 (s ¼ 2.25  0.25) IIa: Hb ¼ 101.51.84 Mv; Hmax ¼ 95.40.26 Mv; He ¼ 91.6 þ 0.51 Mv (N ¼ 15) IIa: r w 3.1 g/cm3 (a1 ¼ 0.061 km, a2 ¼ 3.10/s) duncertain due to low N

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

September 1e26 (lo ¼ 158 e183 ) R.A. ( ) Decl. ( ) l ( ) lo ( ) 167.0 141.3 þ9.7 332.5 þ0.81 0.25 0.17 a (AU) q (AU) e i ( ) 2.70 0.076 0.975 17.1 0.0300 0.0177 8.01 0.0020 þ0.0007 þ0.23 2.35 0.0585 0.975 20.2 N ¼ 1,383

Age:

From c: 9800 y

b ( ) 5.0 þ0.01 u ( ) 208.7 6.05 0.39 204.8

Vg (km/s) 41.3 0.12 U ( ) 346.6 6.46 þ1.00 354.0

P ( ) 197.3  6.05 þ0.61 198.8

e R[S] e R[1]

Brief history: First identified from CMOR radar data by [1] with radiant at R.A. ¼ 145.6 , Decl. ¼ þ8.7 with Vg ¼ 41.7 km/s around lo ¼ 174.0 . Confirmed from SAAMER data here. Name and number by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81. October 14 (lo ¼ 202 )

926 OMH d October mu Hydrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age:

Long-period comet, TJ ¼ þ0.30  0.34 Annual shower October 5e22 (lo ¼ 191 e209 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 201.5 154.0 23.8 325.3 31.5 47.7 þ0.54 0.59 0.18 0.32 0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 49.5 0.377 0.993 74.9 255.9 21.5 276.8 eV 0.0564 0.0262 2.42 7.19 4.70 7.19 þ0.0060 0.0013 þ0.16 þ0.69 þ1.00 þ1.68 w0.3/h (N ¼ 34, hr ¼ 25.6 , m(Mv ¼ 0) ¼ 0.05 g) c ¼ 3.86  0.42 (s ¼ 2.47  0.12) I: Hb ¼ 109.11.31 Mv; Hmax ¼ 96.9 þ 2.01 Mv; He ¼ 92.6 þ 2.13 Mv (N ¼ 26) I: r w 1.2 g/cm3 (a1 ¼ 0.549 km, a2 ¼ 1.94/s) duncertain due to low N From c and s: w45,000 y

Brief history: Shower elongated along toroidal source. First detected by [1] from R.A. ¼ 154.5 , Decl. ¼ 18.7 and Vg ¼ 46.7 km/s around lo ¼ 196.0 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

698

Helion source

699

November

November 4 (lo ¼ 222 )

895 OAB d October alpha Comae Berenicids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density:

Long-period comet, TJ ¼ þ0.55  0.15 Annual shower October 24eNov. 16 (lo ¼ 210 e233 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 221.8 204.5 þ18.8 333.8 þ26.8 43.7 þ0.76 0.32 0.11 0.00 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 25.2 0.311 0.987 57.0 67.6 221.7 288.6 eV 0.0215 0.0174 1.88 2.83 6.32 2.83 0.0008 0.0002 þ0.20 0.04 þ1.00 þ0.96 w0.2/h (N ¼ 40, hr ¼ 17.3 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.39  0.26 (s ¼ 1.95  0.12) Component I has high He: I: Hb ¼ 107.7  0.72 Mv; Hmax ¼ 100.9 þ 0.96 Mv; He ¼ 95.2 þ 2.35 Mv (N ¼ 18) I: low F ¼ 0.54, fragile meteoroids I: r  1.6 g/cm3 (a1 ¼ 0.049 km, a2 ¼ 3.07/s) euncertain due to low N

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

October 24eNov. 14 (lo ¼ 210 e231 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) 220.7 201.1 þ17.8 331.9 þ1.02 0.32 þ0.12 a (AU) q (AU) e i ( ) 5.38 0.263 0.953 54.4 0.0332 0.0437 4.82 þ0.0029 þ0.0010 0.07 N ¼ 58

Age: Source:

From c and s: w18,000 y; radiant drift sU > su -.-

b ( ) þ24.3 þ0.10 u ( ) 60.1 4.97 þ0.37

Vg (km/s) 42.2 0.00 U ( ) 220.8 5.84 þ1.00

P ( ) 278.5 4.97 þ1.37

e R[M]

Brief history: First detected by [1] with R.A. ¼ 200.6 , Decl. ¼ þ21.7 and Vg ¼ 43.4 km/s around lo ¼ 215.5 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29. October 16 (lo ¼ 203 )

917 OVI d omicron Virginids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Asteroid, Phaethon Complex, TJ ¼ þ3.70  0.87 Annual shower October 13e21 (lo ¼ 200 e208 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 202.6 180.5 þ10.6 333.3 þ10.0 36.7 þ0.81 0.42 0.08 0.07 þ0.08 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.57 0.132 0.918 25.2 35.7 202.6 238.0 eV 0.0234 0.0272 3.12 3.93 2.50 3.93 0.0012 þ0.0013 þ0.10 0.14 1.00 þ0.86 w0.5/h (N ¼ 25, hr ¼ 16.1 , m(Mv ¼ 0) ¼ 0.09 g) c ¼ 2.20  0.91 (s ¼ 1.86  0.40) Component IIa has high end height, Ke > 82 due to shallow entry angle: IIa: Hb ¼ 100.0  0.75 Mv; Hmax ¼ 93.0 þ 1.61 Mv; He ¼ 89.5 þ 1.77 Mv (N ¼ 17) duncertain due to low N IIa: r w 1.7 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 3.48/s)

Meteoroid density:

700

Helion source

701

October

October 18 (lo ¼ 205 )

917 OVI d omicron Virginids (cont.)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

October 07e21 (lo ¼ 194 e208 ) lo ( ) R.A. ( ) Decl. ( ) 199.6 175.1 þ14.3 þ0.45 0.42 a (AU) q (AU) e 1.53 0.124 0.928 0.0314 0.0346 0.0044 þ0.0004 N ¼ 82

Age: Source:

From c: 11,000 y -.-

l ( ) 329.3 0.42 i ( ) 30.3 6.21 0.04

b ( ) þ11.2 0.21 u ( ) 33.7 3.69 0.90

Vg (km/s) 37.3 0.02 U ( ) 199.6 3.78 þ1.00

P ( ) 233.7 3.69 þ0.10

e R[M]

Brief history: First detected by [1] from low-light video detected meteors radiating from R.A. ¼ 179.2 , Decl. ¼ þ10.8 and Vg ¼ 36.4 km/s around lo ¼ 202.5 . Radiant just above and velocity slightly lower than #212. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29. October 26 (lo ¼ 212 )

845 OEV d October eta Virginids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, possible part of Phaethon Complex, TJ ¼ þ2.45  0.61 Annual shower October 13e31 (lo ¼ 200e217 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 211.9 182.6 7.9 332.9 6.2 40.3 þ0.89 0.39 0.03 0.01 þ0.22 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.38 0.091 0.961 19.2 211.1 31.8 243.3 eV 0.0193 0.0114 5.34 4.22 4.44 4.22 0.0014 þ0.0016 þ0.34 0.13 1.00 þ0.87 w0.5/h (N ¼ 20, hr ¼ 7.3 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.41  0.15 (s ¼ 1.95  0.07) Component IIa has high end height, Ke > 82 due to shallow entry angle: IIa: Hb ¼ 101.6 0.96 Mv; Hmax ¼ 95.3 þ 1.20 Mv; He ¼ 91.3 þ 2.45 Mv (N ¼ 14) duncertain due to low N IIa: r w 2.1 g/cm3 (a1 ¼ 0.529 km, a2 ¼ 1.21/s) From c: 8000 y -.-

Meteoroid density: Age: Source:

Brief history: Southern component to #917. First reported by [1] from R.A. ¼ 181.6 , Decl. ¼ 7.5 and Vg ¼ 40.7 km/s around lo ¼ 211.5 . Shower also detected in SAAMER data. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

702

Helion source

October

703

704

Helion source

705

December

December 21 (lo ¼ 269 )

783 ILU d iota Lupids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet or asteroid, sunskirter, TJ ¼ þ3.95  0.39 Annual shower December 17e23 (lo ¼ 265 e271 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 267.9 214.1 42.4 318.7 27.1 41.9 þ1.33 0.06 þ0.04 þ0.31 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.44 0.242 0.837 73.5 228.2 87.9 316.5 eV 0.0167 0.0530 6.11 8.29 1.50 8.29 0.0022 þ0.0006 þ0.10 0.32 þ1.00 þ0.67 w0.5/h (N ¼ 32, hr ¼ 26.7 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.73  0.17 (s ¼ 2.09  0.07) IIb: Hb ¼ 97.4 þ 0.57 Mv; Hmax ¼ 90.4 þ 1.83 Mv; He ¼ 86.0 þ 1.83 Mv (N ¼ 30) IIb: r w 2.2 g/cm3 (a1 ¼ 0.093 km, a2 ¼ 3.80/s) e uncertain due to low N

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

December 15e25 (lo ¼ 263 e273 ) R.A. ( ) Decl. ( ) lo ( ) 268.9 212.6 43.0 þ1.06 0.19 a (AU) q (AU) e 1.01 0.227 0.782 0.038 0.043 0.0016 þ0.0023 1.05 0.268 0.744 N ¼ 609

Age: Source:

From c: 25,000 y -.-

l ( ) 317.0 0.08 i ( ) 65.7 10.0 þ0.43 66.2

b ( ) 28.2 þ0.12 u ( ) 219.8 7.6 0.06 225.1

Vg (km/s) 37.0 þ0.17 U ( ) 88.8 2.0 þ1.00 91.0

P ( ) 308.9 7.7 þ0.94 316.1

e R[S] e R[1]

Brief history: Shower first reported by [1] from SAAMER radar data R.A. ¼ 213.0 , Decl. ¼ 46.1 and Vg ¼ 37.0 km/s around lo ¼ 271 . Video-detected meteors are found slightly north of the radiant center. Name and number assigned by [1]. References: [1] Pokorny P., Janches D., Brown P. G., Hormaechea J. L. (2017) Icarus 290, 162e182.

706

Helion source

707

December

December 26 (lo ¼ 274 )

320 OSE d omega Serpentids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density:

Jupiter-family comet or asteroid, TJ ¼ þ4.16  1.00 Annual shower December 7eJan. 11 (lo ¼ 256 e291 ) R.A. ( ) Decl. ( ) l ( ) b ( ) lo ( ) 273.9 241.2 1.0 325.9 þ19.4 þ0.74 0.04 0.21 þ0.12 a (AU) q (AU) e i ( ) u ( ) 1.40 0.159 0.887 53.4 37.9 0.0303 0.0503 8.87 3.95 þ0.0001 0.0011 þ0.41 0.09 1.60 0.156 0.899 56.8 38.8 N ¼ 5350 (m(Mv ¼ 0) ¼ 0.08 g) -.r w 0.7e3.5 g/cm3

eR

Vg (km/s) 38.7 0.01 U ( ) 273.9 6.73 þ1.00 275.5

P ( ) 311.7 3.95 þ0.91 314.3

e R[S] e R[1]

Brief history: Component of #330 (s-Serpentids), first identified by [1] from CMOR radar orbits. Name given as “omega Serpentids” with code “OMS.” From wavelet analysis of 29.85 MHz observations, a radiant was found at R.A. ¼ 242.7 , Decl. ¼ þ0.7 and Vg ¼ 38.9  3.4 km/s around lo ¼ 275.5 , 4 higher in declination than #330 (at R.A. ¼ 244.8 , Decl. ¼ 3.7 and Vg ¼ 42.7  4.0 km/s). This component was not detected by [2], but here confirmed in SAAMER data. There is no clear separation between the two showers, instead #320 is identified as the tail of radiants stretching north from #330. Not detected in video observations. Name and number by [1]. Fig. 9.5 shows AMOR data this time of year. References: [1] Brown P., Weryk R. J., Wong D. K., Jones J. (2008) Icarus 195, 317e339; [2] Brown P., et al. (2010) Icarus 207, 66e81.

FIG 9.5

Detection of Daytime x-Sagittariids in 1990e99 AMOR data (partial sky coverage).

708

Helion source

709

January

January 7 (lo ¼ 287 )

100 XSA d Daytime xi Sagittariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, TJ ¼ þ3.92  0.66 Annual shower December 20eJan. 22 (lo ¼ 269 e302 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) 286.9 281.0 16.7 354.3 þ6.3 þ0.67 þ0.05 0.34 þ0.00 a (AU) q (AU) e i ( ) u ( ) 1.67 0.505 0.701 5.1 79.4 0.0460 0.0756 1.29 5.23 0.0050 þ0.0000 þ0.04 0.72 1.74 0.383 0.780 4.3 66.6 N ¼ 6867 (m(Mv ¼ 0) ¼ 0.30 g) -.r w 0.4e2.8 g/cm3 -.-.-

eR

Vg (km/s) 22.3 þ0.07 U ( ) 286.8 6.74 þ1.00 296.0

P ( ) 5.9 5.23 þ0.28 2.6

e R[S] e R[1]

Brief history: First identified by [1] from Harvard Meteor Project radar data at R.A. ¼ 284.1 , Decl. ¼ 18.7 and Vg ¼ 26.3 km/s around lo ¼ 295.3 (B1950), called “January Sagittariids.” [1] also found a second shower from nearby R.A. ¼ 283.2 , Decl. ¼ 21.9  and Vg ¼ 24.4 km/s later around lo ¼ 304.9 (B1950) called “xi Sagittariids.” Those positions are at the edge of the radiant point cloud. [2] detected the shower in radar data at Davis Station, Antarctica, and Darwin, Australia, with a radiant at R.A. ¼ 281.7 , Decl. ¼ 19.5 around lo ¼ 288 and called it the “chi Sagittariids.” Also detected by [3] over lo ¼ 278e296 . Name and number by [4]. References: [1] Sekanina Z. (1976) Icarus 27, 265e321; [2] Younger J. P., Reid I. M., Vincent R. A., Holdsworth D. A., Murphy D. J. (2009) MNRAS 398, 353e354; [3] Brown P., et al. (2010) Icarus 207, 66e81; [4] Jenniskens P. (2006) Meteor Showers and their parent Comets, Cambridge: CUP, p. 684. December 25 (lo ¼ 274 )

1209 FOS d 58 Ophiuchids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Meteoroid density: Age: Source:

Jupiter-family comet or asteroid, TJ ¼ þ4.09  0.49 Annual shower December 19eJan. 1 (lo ¼ 268 e280 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 274.4 267.0 18.5 352.9 þ4.9 þ0.55 0.03 0.46 0.02 a (AU) q (AU) e i ( ) u ( ) 1.59 0.505 0.694 4.2 76.4 0.0441 0.0783 1.04 4.11 0.0061 0.0016 þ0.02 1.00 N ¼ 1549 (m(Mv ¼ 0) ¼ 0.29 g) -.r w 0.4e2.8 g/cm3 -.-.-

eR

Vg (km/s) 22.5 þ0.02 U ( ) 274.3 3.16 þ1.00

P ( ) 351.0 4.11 þ0.00

e R[S]

Brief history: First identified here as separate from #100 in l versus lo diagram based on SAAMER radar data described in [1]. References: [1] Bruzzone J. S., et al. (2020) PSS 188, article id. 104936.

710

Helion source

711

February

January 21 (lo ¼ 299 )

114 DXC e Daytime chi Capricornids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, TJ ¼ +2.82  0.25 Annual shower January 13 e 22 (lo ¼ 293 e 302 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 299.6 305.7 -30.9 361.8 +0.74 +0.25 -0.32 a (AU) q (AU) e i ( ) 2.70 0.591 0.781 8.00 0.0081 0.0296 1.17 -0.0076 +0.0012 +0.02 w0.7 /h (N ¼ 8, hr ¼ 2.3 , m(Mv¼0) ¼ 0.29 g) c ¼ 3.81  0.61 (s ¼ 2.45  0.18) IIa: Hb ¼ 95.8 + 2.27 Mv; Hmax ¼ 91.0 + 3.16 Mv; IIa: r w 6.2 g/cm3 (a1 ¼ 2.53 km, a2 ¼ 0.25 /s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

January 7 e Feb. 6 (lo ¼ 287 e 317 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 300.6 303.5 -29.2 359.9 +0.63 +0.21 -0.40 a (AU) q (AU) e i ( ) 2.04 0.578 0.721 6.65 0.0382 0.0776 1.21 -0.0064 +0.0014 +0.02 2.67 0.556 0.792 7.3 N ¼ 4,880

b ( ) -9.4 +0.08 u ( ) 270.8 4.37 -0.83 270.9

Vg (km/s) 21.7 +0.14 U ( ) 120.7 7.36 +1.00 121.0

P ( ) 31.9 4.37 +0.17 31.9

Age: Source: Orbital elements (J2000.0) Epoch 2007-Dec-30.0 TDB Source: Epoch 2007-Dec-30.0 TDB

-.2017 MB1 a (AU) 2.37 169P/NEAT 2.60

b ( ) -11.2 +0.10 u ( ) 275.1 0.54 -0.97

Vg (km/s) 22.9 +0.39 U ( ) 119.6 2.33 +1.00

P ( ) 34.7 0.54 +0.03

eV

He ¼ 88.9 + 3.37 Mv (N ¼ 7) e uncertain due to low N

q (AU) 0.589

e 0.752

i ( ) 8.5

u ( ) 264.7

U ( ) 126.9

P ( ) 32.6

0.607

0.767

11.3

218.0

176.2

34.2

e R[S] e R[2]

Brief history: Perhaps two showers over lo ¼ 285 e 304 and 304 e 322 intervals, respectively. First reported by [1] from Harvard Meteor Radio Project data with R.A. ¼ 315.0 , Decl. ¼ -23.3 and Vg ¼ 26.8 km/s around lo ¼ 325.1 called “chi Capricornids”. Confirmed by [2] from CMOR radar observations with radiant at R.A. ¼ 304.7 , Decl. ¼ -29.2 , Vg ¼ 23.8 km/s around lo ¼ 301.0 (called “Daytime chi Capricornids”). Detection in CAMS low-light video observations reported here. Name by [1], number by [3]. References: [1] Sekanina Z. (1973) Icarus 18, 257e259; [2] Brown P., Wong D. K., Weryk R. J., Wiegert P. (2010) Icarus 207, 66e81; [3] Jenniskens P. (2006) Meteor Showers and their parent Comets. Cambridge: CUP, p. 684.

712

Helion source

713

February

February 1 (lo ¼ 312 )

115 DCS d Daytime CapricornidseSagittariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Magn. distribution index: Meteoroid density: Source:

Jupiter-family comet or asteroid, TJ ¼ þ3.54  0.49 Annual shower January 24eFebruary 8 (lo ¼ 304 e319 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) 311.5 311.0 26.9 355.7 8.5 þ0.81 þ0.22 0.22 þ0.04 a (AU) q (AU) e i ( ) u ( ) 1.91 0.506 0.735 6.72 261.7 0.0348 0.0578 1.04 3.26 0.0047 þ0.0030 þ0.05 0.49 1.68 0.355 0.792 73.0 93.1 N ¼ 1391 (m(Mv ¼ 0) ¼ 0.27 g) e r w 0.4e3.9 g/cm3 e

eR

Vg (km/s) 23.2 þ0.15 U ( ) 131.6 3.63 þ1.00 242.0

P ( ) 33.0 3.26 þ0.50 335.1

e R[S] e R[1]

Brief history: First identified by [1] from Harvard Meteor Project radar data with R.A. ¼ 315 , Decl. ¼ 23.3 and Vg ¼ 26.8 km/s around lo ¼ 325.1 during the 1961/1965 observing seasons. Perhaps related to the nearby shower below. Name by [1], number by [2]. References: [1] Sekanina Z. (1973) Icarus 18, 253e284; [2] Jenniskens P. (2006) Meteor Showers and their parent Comets, Cambridge: CUP, p. 684. Jan. 19 (lo ¼ 298 ).

1208 OES e 62 Sagittariids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density:

Jupiter-family comet, TJ ¼ þ2.88  0.50 Annual shower January 12 e 22 (lo ¼ 292 e 302 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 297.9 305.6 -30.4 2.4 -10.7 22.5 þ0.36 0.02 0.71 0.09 þ0.68 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.63 0.609 0.776 7.79 277.5 117.9 35.1 eV 0.0250 0.0454 1.28 3.03 3.73 3.03 0.0137 þ0.0173 þ0.34 1.26 þ1.00 0.26 w0.01 /h (N ¼ 9, hr ¼ 2.7 , m(Mv ¼ 0) ¼ 0.30 g) c ¼ 3.09  0.50 (s ¼ 2.22  0.18) IIa: Hb ¼ 94.8 þ 1.22 Mv; Hmax ¼ 88.4 þ 2.51 Mv; He ¼ 85.1 þ 3.39 Mv (N ¼ 9) euncertain due to low N IIa: r w 3.9 g/cm3 (a1 ¼ 2.75 km, a2 ¼ 0.40 /s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

January 5 e Feb. 1 (lo ¼ 285 e 312 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 296.8 302.2 -30.2 1.3 þ0.95 þ0.20 0.13 a (AU) q (AU) e i ( ) 2.14 0.600 0.721 6.68 0.0321 0.0721 1.15 0.0024 þ0.0012 þ0.02 1.68 0.355 0.792 73.0 N ¼ 2,827

b ( ) -9.9 þ0.02 u ( ) 273.6 3.33 0.28 93.1

Vg (km/s) 21.3 þ0.07 U ( ) 116.9 5.10 þ1.00 242.0

P ( ) 31.5 3.33 þ0.72 335.1

eR[S] eR[1]

Brief history: First identified by [1] from CMOR radar data with R.A. ¼ 304.7 , Decl. ¼ 29.2 and Vg ¼ 22.8 km/s around lo ¼ 301 . Identified as shower #115, but that name is reserved for a later shower slightly offset in l v.s. lo diagram. Weak video detection here. Name and number here. References: [1] Brown P., et al. (2010) Icarus 207, 66e81.

714

Helion source

18 AND e Andromedids

C H A P T E R

10

Northern antapex

Atlas of Earth's Meteor Showers https://doi.org/10.1016/B978-0-323-88447-1.00008-9

715

© 2024 Elsevier Inc. All rights reserved.

716

Northern antapex

June

717

April 21 (lo ¼ 31 )

923 FBO d 15 Bootids

Dynamic type: Shower type: Years of outbursts:

Mellish-type shower, TJ ¼ þ1.12  0.13 Episodic shower 2013e2014: lo ¼ 30.72e31.00 2019: lo ¼ 31.23e31.34 April 19e24 (lo ¼ 29e33 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 31.12 213.3 þ11.3 175.9 þ23.2 27.8 þ1.09 0.08 þ0.12 þ0.31 þ0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 25.6 0.639 0.979 19.2 254.8 31.1 285.8 eV 1 0.0058 0.0185 0.39 0.85 0.29 0.85 ) 0.0002 0.0008 þ0.30 þ0.07 þ1.00 þ1.07 1 var. (N ¼ 23, hr ¼ 49.5 , m(Mv ¼ 0) ¼ 0.18 g) ) core c ¼ 1.71  0.18 (s ¼ 1.58  0.12) Ib: Hb ¼ 101.0  1.32 Mv; Hmax ¼ 91.2 þ 0.60 Mv; He ¼ 86.1 þ 1.23 Mv (N ¼ 18) Ib: F ¼ 0.66: not fragile Ib: r  1.7 g/cm3 (a1 ¼ 0.037 km, a2 ¼ 5.92/s) elow N From c and s: 3000 y C/539 W1 e uncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) N 0.16 1.00 19 246 33 279 e [7] 90 0.630 0.993 19.2 253.4 33.3 286.7 e [6] C/1245 D1 e uncertain N 0.50 1.00 20 87 180 267 e [7] N 0.61 1.00 26 252 52 304 e [6] 82 0.627 0.992 19.4 254.4 31.7 286.1 e [6] *) Epoch assumed to be the perihelion time

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 539-Nov-06.0 TDB Epoch 539-Sep-15.0 TDB* Source: Epoch 1245-Apr-1.0 TDB Epoch 1245-Apr-12.0 TDB* Epoch 1245-Apr-09.0 TDB*

Brief history: Shower first isolated by [1] as a few video meteors in a tight cluster from R.A. ¼ 213.1 , Decl. ¼ þ11.2 and Vg ¼ 27.5 km/s around lo ¼ 30.9 in 2013e2014. May be same as removed shower #454 [3]. Shower recognized to be active again in 2019 [2e5]. Relatively rich in bright meteors. Models show rapid precession due to low inclination. Predictions for future returns in [4]. Possible source 539 W1 identified by [2], but with historic observations suggesting a lower perihelion distance according to orbit calculations by [7]. [4] showed that historic observations can reasonably match the 15-Bootid orbit, and suggested that the relatively short median semi-major axis of the 15-Bootids orbit could imply that the comet had returned to the solar system more than once since 539 CE, possibly sometime around 1260 CE. Suggestions for an observing strategy to search for the comet’s anticipated return to the inner solar system were given. Subsequently, [6] proposed 1245 D1 may have been this return, recalculating its orbit from historic observations. Table above shows the backward integrated orbital elements from a combination of comet and meteor observations. Name and number by [1]. References: [1] Jenniskens P. et al. (2018) PSS 154, 21e29; [2] Jenniskens P. (2019) CBET 4624. Ed.: D. W. E Green, Cambridge: CBAT, issued May 10, p. 1e1; [3] Roggemans P. (2019) eMeteorNews 4, 216e219; [4] Jenniskens P., Lyytinen E., Johannink C., Odeh M., Moskovitz N., Abbott T. M. C. (2020) PSS 181, id 104829; [5] Johannink C. (2019) eMeteorNews 4, 213e215; [6] Usó M. J., Marco F. J. (2021) PSS 204, id. 105282; [7] Hasegawa I. (1979) PASJ 31, 257e270.

June 8 (lo ¼ 78 )

61 TAH d tau Herculids

Dynamic type: Shower type: Years of outbursts:

Jupiter-family comet, TJ ¼ þ2.73  0.31 Episodic shower 1930?: June 9/10, Japan; lo w 78.00 , ZHR w 50/h?? 1970: May 30, Japan; low rates 2001: May 30, Europe; lo w 68.62e69.09 2011: June 2, USA; lo w 71.23e35

e 1925/30-dust trail [7,12] e 1925-dust trail e 1941-dust trail e 1952-dust trail

718

Northern antapex

June

June 8 (lo ¼ 78 )

719

61 TAH d tau Herculids (cont.)

2017: May 31, BeNeLux; lo w 68.74e70.39 [9] e 1941-dust trail 2019: June 8; lo w 72.92e79.92 2022: May 31; lo ¼ 69.436  0.017 , ZHR ¼ 40  3/h, W ¼ 3.5 h e1995-debris Period of activity: June 2e10 (lo ¼ 72 e80 ) Shower radiant/speed lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) Median (geocentric): 77.9 231.0 þ36.4 135.7 þ52.6 15.2 e 2019 Drift per day (d/dlo): þ0.57 0.24 0.15 0.03 þ0.15 Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Median: 3.14 0.981 0.687 18.9 203.3 77.9 280.6 e 2019 Dispersion (±s): 0.0019 0.0600 1.31 0.40 2.21 0.40 Drift (d/dlo): 0.0000 þ0.0106 þ0.13 0.06 þ1.00 þ0.94 Peak ZHR: var. (N ¼ 2370, hr ¼ 54.5 , m(Mv ¼ 0) ¼ 0.64 g) Magn. distribution index: 2022: c ¼ 3.21  0.53 (s ¼ 2.27  0.19), bright ( 0 mag.): w2.5, faint: w3.8; 2.5  0.1 [14] Lightcurve: Ib: Hb ¼ 94.3  0.88 Mv; Hmax ¼ 86.2 þ 0.65 Mv; He ¼ 81.3 þ 1.26 Mv (N ¼ 2329) Meteoroid density: r w 0.25 g/cm3 [18] Ib: r w 0.28  0.05 g/cm3 (a1 ¼ 0.269 km, a2 ¼ 2.83/s) Spectroscopy: Mg0.71 Fe2.06 Na0.084 (N ¼ 2), Fe enhanced, sp: continuum þ strong Na line Age: 2022 outburst: 27 y Source: 73P/Schwassmann-Wachmann 3 Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Epoch 2017-Feb-16.0 TDB 3.09 0.972 0.686 11.2 199.4 69.7 269.1

Brief history: Following discovery of comet 73P in 1930, [1] reported faint meteor shower from R.A. ¼ 234.0e236.3 , Decl. ¼ þ41.5e42.0 (B1930). [11] pointed out this position conformed to an erroneously predicted radiant, 10 away from the theoretical radiant calculated now. [2,10] found two photographed meteor orbits similar to 73P. [3] rejected 1, but found 7 others. Weak activity observed in dedicated obFIG 10.1 2022 tau-Herculid. servations in 2001 on May 30 [4]. On 2011, June 2, CAMS [8] detected 3 s-Herculids from R.A. ¼ 215.5  0.4 , Decl. ¼ þ34.0  0.6 with Vg ¼ 12.55  0.09 km/s from the 1952 dust trail encounter predicted by [5] at R.A. ¼ 214.2 , Decl. ¼ þ33.5 and Vg ¼ 12.9 km/s. In 2017, CAMS BeNeLux detected 5 s-Herculids [5] from encounter with 1941-dust trail [9] from R.A. ¼ 212.6 , Decl. ¼ þ29.7 and Vg ¼ 12.4 km/s on May 31.136. Weak video activity found here in 2019 (“þ” in map is theoretical radiant, precessing along dashed line over time). [5,6,12] note that there was no predicted dust trail encounter in 1930, but [7] lists calculations by M. Sato who had 1925 CE dust trail in Earth’s path. Model by [5,16] predicted shower in 2022 from the 1995 breakup debris of 73P. [17] pointed out that 2022 shower to occur only if the ejection velocities were a factor of 2.5 higher than predicted from normal comet gas ejection during the breakup. Because the comet gas production rate was an order of magnitude higher, the expected ejection velocities were a factor of 2.7 higher. An outburst was observed [13e15] (Fig. 10.1). Peak modeled by 1995 ejecta, while tail in radiant map modeled by dust trails ejected in 1930e1941 [19]. Name by [2], number by [10]. References: [1] Nakamura K. (1930) MNRAS 91, 204e209; [2] Southworth R. B., Hawkins G. S. (1963) SCoA 7, 261; [3] Lindblad B. A. (1971) SCoA 12, 1e13; [4] Arlt R. (2001) JIMO 29, 93e95; [5] Lüthen H., et al. (2001) JIMO 29, 15e28; [6] Wiegert P. A., et al. (2005) MNRAS 361, 638e644; [7] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [8] Jenniskens P., et al. (2011) CBET 2817, Ed.: D. W. E. Green, Cambridge: CBAT, 1 pp; [9] Johannink C., et al. (2017) eMeteorNews 2, 102e104; [10] McCrosky R. E., Posen A. (1961) SCoA 4, 15e84; [11] Arlt R., Vaubaillon J. (2006) JIMO 34, 15e18; [12] Vaubaillon J. (2021) 31st of May 2022 s-Herculids. On IMCCE website (last accessed 2022 May 3); [13] Jenniskens P. (2022) CBET 5126, Ed.: D.W.E. Green, Cambridge: CBAT, 1 pp; [14] Jenniskens P. (2022) eMeteorNews 7, 228e229 and 230e231; [15] Ogawa H., Sugimoto H. (2022) eMeteorNews 7, 232e235; [16] Horii S., Watanabe J.-I., Sato M. (2008) EMP 102, 85e89; [17] Ye Q., Vaubaillon J. (2022) MNRAS 515, L45e49. [18] Buccongello N., et al. (2023) In: Asteroids, Comets, Meteors 2023 (LPI Contrib. No. 2851), Abstract 2464; [19] Egal A., et al. (2023) ApJ 949, 96e204.

720

Northern antapex

June

721

June 16 (lo ¼ 83 )

21 AVB d alpha Virginids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.01  0.15 Annual shower May 21eJuly 13 (lo ¼ 60 e111 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 83.4 229.3 þ47.1 118.5 þ58.8 14.2 þ0.29y þ1.13y þ1.89y þ0.96y þ0.06 At lo ¼ 83 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.67 1.005 0.628 18.1 192.0 83.4 276.6 eV 0.0146 0.0701 2.44 2.89 11.52 2.89 þ0.0018 0.0011 þ0.17 1.15 þ1.00 0.15 2.56 0.720 0.715 2.0 250.5 45.7 296.7 e P[1] w0.2/h (N ¼ 375, hr ¼ 66.8 , m(Mv ¼ 0) ¼ 0.72 g) c ¼ 2.55  0.11 (s ¼ 2.01  0.05) Component IIa has high He, Ke > 82; IIb has low He, ke < 79, like III: IIa: Hb ¼ 91.3  0.76 Mv; Hmax ¼ 81.8 þ 1.05 Mv; He ¼ 76.9 þ 1.58 Mv (N ¼ 202) IIb: Hb ¼ 82.4  0.52 Mv; Hmax ¼ 76.2 þ 1.05 Mv; He ¼ 71.9 þ 2.05 Mv (N ¼ 57) IIa: r w 2.0  0.6 g/cm3 (a1 ¼ 0.036 km, a2 ¼ 3.74/s) IIb: r w 7.0 (a1 ¼ 0.052 km, a2 ¼ 5.47/s) d perhaps Na free or irons e 1998 SH2 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.74 0.785 0.714 2.40 268.4 6.4 274.8

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2023-Sep-13.0 TDB

Brief history: This shower was first detected from 1952 to 1954 Harvard SuperSchmidt program photographed meteors by [1]. [5] shows that in 1953, four meteors radiated from R.A. ¼ 214.0  3.3 , Decl. ¼ 12.5  3.6 with Vg ¼ 17.5  0.7 km/s around lo ¼ 46.5 , with range 45e48 (B1950.0). The shower was again detected in 1954, when 6 meteors FIG 10.2 Radiant evolution of alpha Virginids. radiated from R.A. ¼ 214.0  2.5 ,  Decl. ¼ 13.5  5.6 with Vg ¼ 20.4  2.4 km/s around lo ¼ 43.0 , during range lo ¼ 40e45 (B1950.0). Name “alpha-Virginids” given by [1] and number 21 was assigned by [5]. Dataset stood out from sporadic background of anthelion source also in later efforts to extract showers from photographic orbits [2]. Jupiter-family comet showers tend to evolve quickly and 50 years later, there might not have been any trace left. However, we detected in CAMS data a faint shower at high latitude (#186) that aligns in the evolution of orbital elements as a function of P and node with those early alpha Virginids. There is also a strong shower at lower ecliptic latitude that aligns in radiant evolution with the AVB, but not in the evolution of speed (Fig. 10.2, and Chapter 2, shower #136). As a result, the orbital elements also don’t evolve smoothly. We assumed here that both are from the same source, but representing different episodes of activity. The orbital elements presented here are those of the higher latitude component that most directly aligns with the 1953/54 ejecta. Association of low albedo asteroid 1998 SH2 to “sigma Leonids” by [3], link to #21 by [4]. References: [1] McCrosky R. E., Posen A. (1959) AJ 64, 25e27; [2] Lindblad B. A. (1971) SCoA 12, 1e13; [3] Wiegert P., Brown P. (2004) EMP 95, 19e26; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 704; [5] McCrosky R. E., Posen A. (1961) SCoA 4, 15e84.

722

Northern antapex

June

June 22 (lo ¼ 92 )

723

170 JBO d June Bootids

Jupiter-family comet, TJ ¼ þ2.84  0.24 Episodic shower 1916: lo ¼ 98.1  0.1 , c ¼ 2.20  0.10, w 200  50/h [3,4], 100 kg/activity period [12] 1921: ZHR w 7  5 [4]; 1927: ZHR < 30 [3] 1998: lo ¼ 95.69  0.01 , 250  50/h, B ¼ 2.5/ , c ¼ 2.05  0.05 [3,4], 145 kg/ap [12] 2004: lo ¼ 92.21  0.01 , ZHR ¼ 18  2, c ¼ 2.3  0.2 [4] 2010: lo ¼ 92.24  0.08 , W ¼ 0.67  0.12 ; ZHR ¼ 5  2/h [10] 2016: lo ¼ 90.15  0.04 (N ¼ 4) 2022: lo ¼ 90.27  0.08 , W ¼ 0.90  0.07 (221.2 1.9 , þ48.6  1.2 , 14.3  1.1 km/s) Calculated trail crossings: 1916: 1819-trail, lo ¼ 98.0e98.3 [4] 1998: 1813e1852 trails, lo ¼ 95.6e96.3 [4] 2004: 1813e1852 trails, lo ¼ 92.1e92.6 , ZHR ¼ 18  2, FWHM ¼ 12  2 h [4] 2010: 1819, 1825, 1830, 1836 trails, lo ¼ 92.2e92.4 [4] 2016: 1921 trail, lo ¼ 91.7 , requiring high 97 m/s ejection speed [15] Period of activity: June 21e23 (lo ¼ 91.8 e93.2 , in 2010) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) Shower radiant/speed lo ( ) Median (geocentric): 92.25 223.5 þ47.2 103.0 þ59.1 13.8 (2010) Drift per day (d/dlo): þ0.84 0.22 þ0.15 þ0.14 þ0.24 Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Median: 3.06 1.014 0.669 18.1 185.6 92.2 277.9 Dispersion (±s): 0.0005 0.052 1.07 0.65 0.34 0.65 Drift (d/dlo): 0.0002 þ0.0090 þ0.27 þ0.30 þ1.00 þ1.30 Number observed: 2010: N ¼ 20; 2022: N ¼ 28 (hr ¼ 60.0 , m(Mv ¼ 0) ¼ 0.75 g) Peak ZHR: Low or absent ZHR w0.3/h [16], up to ZHR ¼ 100/h in outburst years Magn. distribution index: 2022: c ¼ 2.33  0.21 (s ¼ 1.92  0.10); 1998: 2.05  0.05 [3]; 2.2, var [13] Lightcurve: Ib: Hb ¼ 92.07  0.88 Mv; Hmax ¼ 82.4 þ 1.26 Mv; He ¼ 78.0 þ 1.76 Mv (N ¼ 35) Meteoroid density: Ib: r w 0.94 g/cm3 (a1 ¼ 0.099 km, a2 ¼ 3.71/s); 0.6e2.2 g/cm3 [14] Age: w180 y Source: 7P/Pons-Winnecke Orbital elements (J2000.0) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) Epoch 2012-Sep-28.0 TDB 3.43 1.251 0.635 22.3 172.2 93.4 264.8 Epoch 2019-Jul-25.0 TDB 3.14 0.772 0.754 22.3 162.0 115.5 277.5 Dynamic type: Shower type: Years of outbursts:

Brief history: First detected visually by [1] on June 27, 1916. Meteors radiated from near iDraconis, with short paths and end flares. Few meteors observed in the next return in 2021. Details in [2e4]. [5] also identified the parent body as 7P. Association confirmed by [6]. First trail model identifying 1819 dust from 7P as the source by [7]. June 27, 1998, surprise outburst of relatively bright meteors [3e4]. 2016 observations reported here from EDMOND and CMN video networks. Radar detection by [11], called “alpha Draconids” Model by [8] showed dust possibly librating about 2:1 resonance. Contributions from several years: dust trails are wide and elongated in direction to the Sun [9]. Number and name by [4]. References: [1] Denning W. F. (1916) MNRAS 76, 740e743; [2] Oliver C. P. (1925) Meteors. Baltimore: Williams & Wilkins, p. 79e81; [3] Arlt R., et al. (1999) MNRAS 308, 887e896; [4] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 334e345; [5] Denning W. F. (1923) MNRAS 84, 43e56 (p.52); [6] Smith F. W. (1932) MNRAS 93, 156e158; [7] Reznikov E. A. (1982) In: Meteoric Material in Interplanetary Space (in Russian). Ed.: O. I. Belkovich et al., Moscow: Kazan, pp. 151e152 (in Russian); [8] Asher D. J., Emel’yanenko V. V. (2002) MNRAS 331, 126e132; [9] Emel’yanenko V. V. (2001) ESA SP 495, 43e45; [10] Jenniskens P., Vaubaillon J. (2010) CBET 2357. Ed.: D.W.E. Green, Cambridge USA: Minor Planet Center, 1 pp; [11] Sekanina Z. (1976) Icarus 27, 265e321; [12] Trigo-Rodríguez J. M., Blum J. (2022) MNRAS 512, 2277e2289; [13] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam:IMO, p. 25; [14] Konovalova, N. A., Madiedo J. M., Trigo-Rodriguez J. M. (2011) 42nd LPSC, abstract id. 1355; [15] Maslov M. (2014) June Bootids 2016: prediction of activity (website: feraj.ru/Radiants/Predictions/Junebootids2016eng.html); [16] Molau S., et al. (2012) JIMO 40, 176e180.

724

Northern antapex

725

June

June 27 (lo ¼ 95 )

63 COR d Corvids

Dynamic type: Shower type: Year of outburst: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Individual orbits:

Jupiter-family comet, TJ w þ3.16 Episodic shower 1937 June 25eJuly 2 (lo ¼ 93 e100 ) R.A. ( ) Decl. ( ) lo (  ) 94.9 191.6 19.2 e e a (AU) q (AU) e 2.460 0.959 0.610 2.367 0.900 0.620 2.461 0.911 0.630 0.0017 þ0.0007 (2.50) 0.930 0.628 ZHR w 13/h [1] c w 1.9 [1] e 300P/Catalina a (AU) q (AU) e 2.69 0.825 0.694

Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Age: Source: Orbital elements (J2000.0) Epoch 2007-Apr-24.0 TDB

l ( ) 102.6 e i ( ) 0.8 1.2 4.3 þ0.09 2.5

b ( ) 13.1 e u ( ) 31.2 45.2 42.8 þ0.08 38.8

Vg (km/s) e e U ( ) 253.9 254.9 263.7 þ1.00 275.7

P ( ) 285.0 300.1 306.5 þ1.08 314.5

i ( ) 5.7

u ( ) 222.7

U ( ) 95.9

P ( ) 318.8

HV7734 HV7750 HV4111 e V[4]

Brief history: The Corvids were detected visually by [1] during a meteor expedition to South-West Africa (now Namibia) during 1937e1938. From 1937 June 25 to July 2, Corvids were detected at a rate of ZHR ¼ 4.1, 13.1, 9.5, 7.8 6.0, 1.7, 0.5, 2.3/h, respectively, radiating from R.A. ¼ 191.6 , Decl. ¼ 19.2 centered on lo ¼ 94.9 (June 27). The orbit above is for an assumed entry velocity so that a ¼ 2.50 AU [1]. Here we note that shower #459 is captured when selecting similar video-detected orbits using a Discriminant criterion DSH, and therefore is likely from the same source, which was identified as 300P by [2]. Perturbations by Jupiter on the orbit of 300P results in a rapid rotation of the nodal line. Name by [1]. Number assigned to Hoffmeister’s shower by [3], based on number given to a tentative shower identified by [4] made up of 1952e53 meteors HV7734, HV7750, and HV4111. Those have similar orbital elements, but a different node (and P). References: [1] Hoffmeister C. (1948) Meteorströme. Leipzig: Verlag Werden und Werken Weimar, p. 138; [2] Jenniskens P., Baggaley W. J., Cooper T., et al. (2019) CBET 4642. Ed.: D.W.E. Green, Cambridge: CBAT, p. 1e1; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets, Cambridge: CUP, p. 712; [4] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129.

726

Northern antapex

July

727

July 10 (lo ¼ 108 )

865 JES d June epsilon Serpentids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.09  0.21 Annual shower June 15eJuly 24 (lo ¼ 84 e122 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 107.8 237.1 þ24.9 120.8 þ43.2 12.1 0.32y þ1.10 1.81y þ0.96 0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.63 1.000 0.628 11.9 197.2 107.8 304.5 eV 0.0135 0.105 1.69 5.17 10.16 5.17 þ0.0030 0.0014 þ0.21 1.25 þ1.00 0.25 w0.2/h (N ¼ 720, hr ¼ 57.0 , m(Mv ¼ 0) ¼ 0.92 g) c ¼ 2.84  0.39 (s ¼ 2.13  0.16) Ib: Hb ¼ 90.4  0.59 Mv; Hmax ¼ 82.3 þ 0.61 Mv; He ¼ 77.5 þ 1.21 Mv (N ¼ 367) III: Hb ¼ 80.5 þ 0.07 Mv; Hmax ¼ 74.6 þ 1.21 Mv; He ¼ 69.8 þ 1.91 Mv (N ¼ 139) Ib: F ¼ 0.64 Ib: r w 1.5  0.4 (a1 ¼ 0.093 km, a2 ¼ 2.61/s) III: r w 3.3 (a1 ¼ 0.143 km, a2 ¼ 2.61/s) d possibly Na poor/free e 2015 LK24 d uncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.67 1.023 0.617 14.4 202.5 94.9 297.4

Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2023-Sep-13.0 TDB

Brief history: Weak shower that moves out of anthelion source toward higher declination. Activity possibly increasing toward lo ¼ 120 , where stream’s q > 1.016 AU and thus no longer detected. First identified by [1] early in that track near b ¼ 24 , when the radiant was at R.A. ¼ 239.1 , Decl. ¼ þ4.5 and Vg ¼ 12.9 km/s around lo ¼ 87.9 . Activity curve in Fig. 10.3. Number and name by [1]. Source identified here has low albedo ¼ 0.043 and 0.306 km diameter object 2015 LK24. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29. FIG 10.3

ZHR profile (scale uncertain).

728

Northern antapex

August

August 7 (lo ¼ 134 )

587 FNC d 59 Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.10  0.61 Annual shower August 2e11 (lo ¼ 130 e139 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 133.8 312.6 þ45.9 205.2 þ59.4 35.2 þ0.88 þ0.56 þ0.59 þ0.14 þ0.10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 11.8 0.842 0.929 54.1 229.9 133.8 3.6 0.0151 0.097 2.11 2.91 1.90 2.91 þ0.0014 0.0020 þ0.31 0.20 þ1.00 þ0.80 w0.12/h (N ¼ 455, hr ¼ 68.3 , m(Mv ¼ 0) ¼ 0.10 g) c ¼ 2.37  0.12 (s ¼ 1.94  0.06) Ib: Hb ¼ 103.4  1.20 Mv; Hmax ¼ 94.7 þ 0.69 Mv; He ¼ 90.2 þ 1.20 Mv (N ¼ 39) III: Hb ¼ 92.3  0.67 Mv; Hmax ¼ 84.1 þ 1.55 Mv; He ¼ 77.7 þ 3.17 Mv (N ¼ 9) Ib: r w 0.65 g/cm3 (a1 ¼ 0.158 km, a2 ¼ 4.46/s) III: Possibly Na poor/free From c and s: w20,000 y e

Meteoroid density: Age: Source:

729

eV

Brief history: First identified from Croatian Meteor Network and SonotaCo video observations by [1] from R.A. ¼ 314.2 , Decl. ¼ þ47.5 and Vg ¼ 35.3 km/s around lo ¼ 137 . Activity curve from the total number of triangulated meteors is shown in Fig. 10.4. Name and number by [1]. References: [1] Gural P., et al. (2014) JIMO 42, 132e138.

FIG 10.4

ZHR profile (vertical scale uncertain).

730

Northern antapex

731

September

September 16 (lo ¼ 173 )

1181 SOS d September 72 Ophiuchids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.12  0.25 Annual shower September 13e23 (lo ¼ 170 e180 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 173.1 271.8 þ11.2 98.9 þ34.5 9.58 þ1.58 0.25 2.88 0.24 þ0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.63 1.0028 0.645 8.22 186.6 173.1 360.0 eV 0.0027 0.125 1.22 2.67 2.09 2.67 þ0.0008 þ0.0016 þ0.02 1.59 þ1.00 0.59 w0.3/h (N ¼ 139, hr ¼ 49.7 , m(Mv ¼ 0) ¼ 1.25 g) c ¼ 2.97  0.04 (s ¼ 2.18  0.02) Ib: Hb ¼ 90.6  0.62 Mv; Hmax ¼ 82.5 þ 0.92 Mv; He ¼ 77.2 þ 1.75 Mv (N ¼ 81) II: Hb ¼ 85.1  2.83 Mv; Hmax ¼ 77.7  0.55 Mv; He ¼ 74.5  0.32 Mv (N ¼ 28) Ib: r w 2.8  0.8 g/cm3 (a1 ¼ 0.760 km, a2 ¼ 1.49/s) II: Possibly Na poor e 2004 QN22 d uncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.49 1.017 0.592 7.11 187.7 163.2 350.9

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2004-Aug-29.0 TDB

Brief history: First identified here. 2004 QN22 can be an interloper instead of the source. Theoretical radiant is at R.A. ¼ 264.0 , Decl. ¼ þ8.3 , Vg ¼ 8.78 km/s around lo ¼ 164.3 . October 1 (lo ¼ 187 )

233 OCC d October Capricornids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.11  0.21 Episodic shower 1972, 1987 September 29eOctober 4 (lo ¼ 186 e192 ) R.A. ( ) Decl. ( ) l ( ) lo ( ) 189.6 295.4 2.0 107.4 þ0.95 0.72 0.15 a (AU) q (AU) e i ( ) 2.60 0.993 0.619 4.3 0.0006 0.0423 0.38 0.0002 þ0.0003 0.22 N ¼ 10 (hr ¼ 52.3 , m(Mv ¼ 0) ¼ 1.38 g) Annual: 0.02/h; 1978e1987: 3.5  1.5 [2] c ¼ 2.85  0.47 (s ¼ 2.14  0.19); 2.81 [1] Meteors are deeply penetrating: IIb: Hb ¼ 81.2 þ 1.09 Mv; Hmax ¼ 74.2 þ 1.46 Mv; IIb: r w 7.3 g/cm3 (a1 ¼ 0.049 km, a2 ¼ 3.16/s) e D/1978 R1 (Haneda-Campos) a (AU) q (AU) e i ( ) 3.29 1.101 0.665 5.95

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1978-Sep-22.0 TDB

b ( ) þ19.1 0.88 u ( ) 191.7 0.45 0.07

Vg (km/s) 8.8 0.04 U ( ) 189.6 1.93 þ1.00

P ( ) 21.1 0.45 þ0.93

eV

He ¼ 68.2 þ 1.82 Mv (N ¼ 6) d uncertain due to low N u ( ) 240.5

U ( ) 132.3

P ( ) 12.8

Brief history: First noticed by Western Australian Meteor Society observers in early October 1971 [1]. From plotted meteors, they found weak radiants near a‐Capricorni during September 27/28 to October 11/12. Reported from routine observations of NAPO-MS between 1971 and 1987 in search of activity from comet D/1978 R1. An outburst was detected on October 2/3, 1972, when ten bright meteors were seen in 35 min by two observers before clouds came in. Most appeared to be fragmenting. Comet evolution studied by [3]. [4] predicted a theoretical radiant at R.A. ¼ 290 , Decl. ¼ 5 for September 28, 1972. Shower focus

732

Northern antapex

October

733

of observing campaign in 1987. Combined with other years, shower active from lo ¼ 178e197 . Radiant was placed at R.A. ¼ 301.5 , Decl. ¼ 8.7 (B1950) on October 2/3. Some more recent video-detected meteors in similar orbits. Name and number by [2]. References: [1] Wood J. (1988) JIMO 16, 191e194; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 345e346; [3] Belyaev N. A., et al. (1986) Catalogue of Short Period Comets. Bratislava: Astron. Inst. Slovak Academy of Science, p. 316e317; [4] Drummond J. (1981) Icarus 47, 500e518. October 5 (lo ¼ 192 )

386 OBC d October beta Camelopardalids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, toroidal shower, TJ ¼ þ0.98  0.29 Annual shower September 1eNovember 14 (lo ¼ 158 e234 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 192.3 32.7 þ45.7 212.0 þ31.5 43.5 þ1.16 þ0.33 þ0.02 0.00 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 7.19 0.362 0.949 65.8 292.6 192.3 120.3 eV 0.0651 0.0294 5.25 8.12 18.05 8.12 0.0002 0.0002 þ0.02 þ0.02 þ1.00 þ1.02 6.57 0.417 0.936 80.9 281.5 214.0 135.5 e R[1] w0.2/h (N ¼ 1659, hr ¼ 62.0 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 3.07  0.16 (s ¼ 2.21  0.06) Component IIa has low He (Ke < 82); IIb has low He, Ke < 79, like III: IIa: Hb ¼ 104.1  0.45 Mv; Hmax ¼ 93.7 þ 1.58 Mv; He ¼ 88.1 þ 1.89 Mv (N ¼ 491) IIb: Hb ¼ 96.6  0.28 Mv; Hmax ¼ 88.5 þ 1.33 Mv; He ¼ 83.8 þ 1.60 Mv (N ¼ 370) IIIb: Hb ¼ 91.4 þ 0.14 Mv; Hmax ¼ 87.4 þ 0.90 Mv; He ¼ 83.8 þ 0.81 Mv (N ¼ 208) IIa: r w 1.1 g/cm3 (a1 ¼ 0.042 km, a2 ¼ 6.03/s) d possibly Na poor IIb: r w 3.0 g/cm3 (a1 ¼ 0.027 km, a2 ¼ 8.32/s) IIIb: r w 2.6 g/cm3 (a1 ¼ 0.028 km, a2 ¼ 12.18/s) d Na free Na0.016 (N ¼ 1), Na depleted From c: w18,000 y, from s (tail): w41,000 y; Radiant drift sU > su e

Meteoroid density:

Spectroscopy: Age: Source:

Brief history: Part of toroidal ring, faint. First reported from 355 CMOR radar-derived trajectories with a mean radiant at R.A. ¼ 66.8 , Decl. ¼ þ56.2 and with Vg ¼ 47.6 km/s around lo ¼ 214.0 with period of activity lo ¼ 194e216 . We find broader range here. Confirmed from video observations by [2] with R.A. ¼ 45.8 , Decl. ¼ þ52.3 and with Vg ¼ 43.6 km/s around lo ¼ 205 . Wide array of beginning heights. Name and number by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81; [2] Jenniskens P., et al. (2016) Icarus 266, 355e370.

734

Northern antapex

October

October 8 (lo ¼ 195 )

9 DRA d October Draconids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index:

Jupiter-family comet, TJ ¼ 2.62  0.17 Episodic shower See Table 10.1. October 7e9 (lo ¼ 194.7 e195.8 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 195.4 262.8 þ55.9 53.3 þ78.8 20.8 þ0.27 þ0.04 1.42 þ0.17 þ0.35 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.36 0.9961 0.704 32.7 173.2 195.4 8.5 0.0015 0.128 1.19 0.93 0.16 0.93 0.0003 0.0019 þ0.65 0.08 þ1.00 þ0.92 N ¼ 1361 (hr ¼ 37.3 , m(Mv ¼ 0) ¼ 0.35 g) Variable; 1933: w10,000, 1946: w10,000 [9] c ¼ 2.96  0.18 (s ¼ 2.18  0.07); c ¼ 3.0  0.2 [27]; also: see Table; 1998: s ¼ 1.81  0.36 [19]; 2005: 2.0  0.1 [20], 1.87  0.15, 2011: 2.0  0.1 [21] 2018: s ¼ 1.74  0.18 (lo ¼ 195.407), s ¼ 2.32  0.27 (lo ¼ 195.436) [34] Component I has high He, fragile: I: Hb ¼ 100.7  0.79 Mv; Hmax ¼ 93.0 þ 0.83 Mv; He ¼ 87.1 þ 1.91 Mv (N ¼ 1058) I: low F ¼ 0.57, fragile meteoroids r ¼ 0.3 g/cm3 (bulk density), 90% porosity if 3.0 g/cm3 grain density [16] r ¼ 0.2 g/cm3 [22] I: r w 0.28  0.04 g/cm3 (a1 ¼ 0.141 km, a2 ¼ 3.68/s) 106 J/m2 sufficient to erode grains early, 30% of largest meteoroids Resist thermal erosion at 15e30 higher energy flux, disrupting mechanically at rairV2 ¼ 5e20 kPa [16,22] Na/Mg ¼ 0.064, Fe/Mg ¼ 0.66 (to 50%) [16]. Nearly chondritic Mg/Si ¼ 1.06, Na/Si ¼ 0.07, Fe/Si ¼ 0.78, Ca/Si ¼ 0.0045, early release of Na [17,18] 7e110 y: dust trail encounters [13] 21P/Giacobini-Zinner a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.50 1.013 0.710 32.0 172.8 195.4 8.2

Lightcurve: Lightcurve shape: Meteoroid density:

Strength:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2017-Nov-06.0 TDB

735

eV e 2018

Brief history: 21P perihelion evolved from well outside to just inside Earth’s orbit following close (D ¼ 0.188 AU) passage by Jupiter on 1898 October 28.0 TT. First seen in 1892, [1,2] predicted that 21P could cause a meteor shower on date of October 10. Visual observers did not detect this shower with certainty in 1913 and 1920 [3]. 21P predicted to pass close to Earth’s orbit in 1926, with Earth passing the node 70 days ahead of the comet. The predicted radiant was at R.A. ¼ 261e265 , Decl. ¼ þ53.5e54.0 [3]. J.P.M. Prentice detected 16 meteors from R.A. ¼ 263 , Decl. ¼ þ54 during 3 h centered on October 9.9 [2], called shower “Giacobinids.” No October Draconids were seen in later years. The orbit evolved closer and Earth passed the node just 80 days after the comet in 1933. A meteor storm was seen in Europe around 20:15 UT on October 9, when meteors were slow and mostly faint. In 1939, the Earth passed the node 136 days ahead of the comet, but no shower seen. In 1946, expectations were high when Earth passed the node 15 days after the comet. A meteor storm was seen in the United States and Canada, as far as south as Venezuela. First singlestation photographic data by [4]. The 1946 storm was the first meteor shower to be detected by radar [5]. [6] detected an ionized layer at 90 km altitude created by the meteors, which lasted 3 h. The 1952 return was observed by Jodrell Bank meteor radar [7] and two Draconids were photographed in the Super Schmidt program, showing these to be the most fragile of meteoroids [8,14]. In 1985, an unexpected outburst was photographed from Japan [9]. Predictions for the 1998 Draconids varied widely and were generally significantly off in time, except for the prediction by [10], an early application of dust trail modeling [see review by 9].

736

Northern antapex

#9 DRA d Draconids

TABLE 10.1 Recorded October Draconid shower dust trail encounters. Date

Time (UTC)

1926-10-09 22:58 1933-10-09 20:07 1946-10-10 03:47

1952-10-09 21:34 1985-10-08 18:58 09:42 1998-10-08 13:10 13:20 1999-10-09 e 2005-10-08 16:06 16:06 2011-10-08 20:07 19:30 2012-10-08 16:48 2017-10-08 e 2018-10-08 23:30 22:21 2020-10-07 01:25 01:57

Eject

lo ( )

Dr (AU)

R.A. ( )

Decl. ( )

Vg (km/s)

lo ( )

W ( )

c

ZHR (/h)

1920 1907 1900 1900 1907 1933 1940 1805 1920 1933 1946 1926, 1926 1959 1966 1946 1953 1900 1907 1966 1959 e 1953 1953 1704 1711

196.910 197.001

þ0.00063 1.018 þ0.00005 þ0.0217

e 0.036

[9] [9,13]

263 265

þ54 þ55

e e

196.9 196.999

e 0.025

e 3.6

e 10,000

[9] [9,25]

196.993 196.993

þ0.00140 þ0.0105 þ0.00179 þ0.0209

0.257 0.299

262.33  0.13 þ54.05  0.04

e

196.992

0.035

3.2

12,000

[9,25]

0.044 e 0.068

[9,13] [9,13] [9,13] [9,13] [9]

197.187 196.933 195.174

þ0.00054 0.0081 þ0.00004 0.0620 0.01140 þ0.0035

271.23

þ47.26

17.12

196.934

0.027

e

250

[9]

[9,13]

264.0

þ54.9

21.1

195.174

0.063  0.012 3.0

150

[9]

195.076

þ0.00033 0.0043

1.025

[9,24]

263.20  0.13 þ55.75  0.19

20.90  0.26 195.08  0.04

0.075

3.0

300

[9]

e

e

e

e

e

e

e

195.72  0.03

e

e

w32

[13]

195.50

e

e

e

[13] [13] [12,13]

256.9  2.2

56.6  1.8

19.90

195.42  0.01

0.069  0.012 2.5  0.3

40

[12]

195.034

0.00076 þ0.0085

0.041

[12,13]

262.92  1.37 þ55.62  0.70

20.05  1.13 195.04  0.07

0.067

3.1  0.6

460  60

195.629

þ0.00140 þ0.0607

e

[12,13]

262.34  1.18 þ55.80  0.84

20.11  0.80 195.69  0.05

0.053

3.1  0.5

w250

This, [27] [13]

e 195.375 195.327 193.960 193.981

e e

e e

e [24,25]

262.85  1.01 þ55.62  0.38 262.71  1.24 þ55.95  0.79

21.13  2.63 194.82  0.07 20.95  1.81 195.38  0.09

0.066 0.095

3.5  0.7 3.3  0.2

e 140  30

2.111 1.293

[9]

e

e

w0.18

e

25  5

Dao (AU)

e e

þ0.00011 þ0.1203 þ0.00019 þ0.1231

fm (AU)

e

194.02  0.05

This This, [22,32] [33]

738

Northern antapex

November

739

Observations summarized by [28]. Meteoroids not quite as fragile, density measured by [22]. [11] detected a 2005 Draconid outburst with CMOR. Results in the Table below from more recent outbursts are from video observations. The anticipated 2011 outburst by [30,31] was observed from aircraft and detected by MU Radar [15] from R.A. ¼ 263.3  0.6 , Decl. ¼ þ55.8  0.2 and Vg ¼ 20.6  0.4 km/s [16]. A smaller outburst occurred in 2018 [23]. First dust trail model by [10], more recent models summarized by [9,13,29]. Name and number by [8]. References: [1] Davidson M. (2015) JBAA 125, 292e292; [2] Davidson M. (1920) MNRAS 80, 739e741; [3] Denning W. F. (1926) MNRAS 87, 104e106; [4] Jacchia L. G., Kopal Z., Millman P. M. (1950) AJ 111, 104e133; [5] Hey J. S., et al. (1947) MNRAS 107, 176e183; [6] Pierce J. A. (1947) Phys. Rev. Ser. 2 71, 88e92; [7] Davies J. G., Lovell A. C. B. (1955) MNRAS 115, 23e31; [8] Jacchia L. G., Verniani F., Briggs R. E. (1967) SCoA 10, 1e139; [9] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [10] Reznikov V. V. (1993) Trudy Kazan Gor. Astron. Obs. 53, 80e101; [11] Campbell-Brown M. D., et al. (2006) AA 451, 339e344; [12] Campbell-Brown M. D., et al. (2021) MNRAS 507, 852e857; [13] Egal A., et al. (2019) Icarus 330, 123e141; [14] Jacchia L. G. (1952) AJ 61, 6e7; [15] Kero J., et al. (2012) Ann. Geophys. 30, 639e659; [16] Borovicka J., et al. (2007) AA 473, 661e672; [17] Madiedo J. M. (2013) MNRAS 433, 571e580; [18] Rudawska R., et al. (2014) Earth, Moon Planets 112, 45e57; [19] Watanabe J.-I., et al. (1998) Geophys. Res. Lett 26, 1117e1120; [20] Koten P., et al. (2007) AA 466, 729e735; [21] Koten P., et al. (2014) Earth Moon Planets 112, 15e31; [22] Borovicka J., et al. (2014) EMP 113, 15e31; [23] Koten P., et al. (2020) PSS 184, id.104871; [24] Maslov M. (2011) JIMO 39, 64e67; [25] Egal A., et al. (2018) ApJ 866, L8eL16; [26] Lovell A. C. B (1954) Meteor Astronomy. Oxford: Clarendon Press, p. 326e337; [27] Molau S., et al. (2019) JIMO 47, 188e192; [28] Kac J. (2015) JIMO 43, 75e80; [29] Sato M. (2003) JIMO 31, 59e63; [30] Maslov M. (2011) JIMO 39, 64e67; [31] Vaubaillon J. (2011) JIMO 39, 59e61; [32] Miskotte K. (2019) eMeteorNews 4, 74e78; [33] Ogawa H. (2020) eMeteorNews 5, 406e407; [34] Vida D., et al. (2020) AA 635, 153e169.

November 3 (lo ¼ 221 )

557 SFD d 64 Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.23  0.16 Annual shower October 23eNovember 13 (lo ¼ 210 e231 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 221.4 301.0 þ64.6 145.3 þ77.0 25.5 0.12 0.16 1.82 0.00 0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 22.2 0.977 0.956 36.7 194.5 221.4 54.9 eV 0.0034 0.0530 1.49 1.65 4.79 1.65 þ0.0005 þ0.0026 0.23 0.35 þ1.00 þ0.65 w0.07/h (N ¼ 251, hr ¼ 51.0 , m(Mv ¼ 0) ¼ 0.22 g) 1.97  0.06 (s ¼ 1.74  0.04) I: Hb ¼ 101.3  1.15 Mv; Hmax ¼ 88.6 þ 1.76 Mv; He ¼ 84.6 þ 1.94 Mv (N ¼ 92) IIa: Hb ¼ 96.2  1.03 Mv; Hmax ¼ 87.3  0.32 Mv; He ¼ 79.3 þ 3.07 Mv (N ¼ 10) F ¼ 0.76 I: r w 1.4 g/cm3 (a1 ¼ 0.070 km, a2 ¼ 2.68/s) IIa: r w 2.1 g/cm3 (a1 ¼ 1.60 km, a2 ¼ 2.68/s) d uncertain due to low N AMOS: Mg1.00 Fe0.75 Na0.059 (N ¼ 1) [2] From c: w5000 y, from s (tail): 31,000 y; radiant drift sU > su e

Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source:

Brief history: First detected from CMN video data by [1] from 37 meteors with radiant R.A. ¼ 302.9 , Decl. ¼ þ65.6 and Vg ¼ 26.4 km/s around lo ¼ 216.0 . Name and number by [1]. References: [1] Andreic Z., Gural P., Segon D., Skokic I., Korlevic K., Vida D., Novoselnik F., Gostinski D. (2014) JIMO 42, 90e97; [2] Matlovic P., et al. (2019) AA 629, A71eA90.

740

Northern antapex

November

741

November 11 (lo ¼ 230 ) 18 AND d Andromedids Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Lightcurve shape: Meteoroid density:

Age: Source: Orbital elements (J2000.0) Epoch 1832-Dec-03.0 TDB

Jupiter-family comet, TJ ¼ þ2.77  0.24 Annual shower, variable, with occasional outbursts See Table 10.2. October 23eDecember 4 (lo ¼ 210 e252 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 230.3 22.2 þ31.7 162.6 þ20.7 17.4 þ0.18 þ0.76 0.51 þ0.64 0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.93 0.801 0.731 10.0 236.7 230.9 107.9 eV 0.0157 0.0722 1.25 2.07 9.68 2.07 þ0.0052 0.0020 þ0.17 0.83 þ1.00 þ0.17 Annual: w0.4/h (N ¼ 1423, hr ¼ 64.3 , m(Mv ¼ 0) ¼ 0.50 g) 3.33  0.10 (s ¼ 2.30  0.05); 2011: s ¼ 2.2 [13] Fragile: I component has high He, low F ¼ 0.54: I: Hb ¼ 98.1  0.99 Mv; Hmax ¼ 90.2 þ 0.38 Mv; He ¼ 83.2 þ 1.47 Mv (N ¼ 1741) IIIb: Hb ¼ 80.8 þ 0.21 Mv; Hmax ¼ 77.2 þ 0.60 Mv; He ¼ 74.5 þ 0.77 Mv (N ¼ 108) I: F ¼ 0.53: fragile r ¼ 1.0 g/cm3 [13] I: r w 0.33  0.05 g/cm3 (a1 ¼ 0.181 km, a2 ¼ 2.87/s), lower if fragile IIIb: r w 2.8 g/cm3 (a1 ¼ 0.087 km, a2 ¼ 7.22/s) d possibly Na poor/free Annual component: w175 y?; outbursts: 26e175 y [14,15] 3D/Biela a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.53 0.879 0.751 13.2 221.7 250.7 112.4

Brief history: Shower long known as “Bielids.” The comets of 1772 (Montaigne) and 1805 (Pons) were recognized to move in similar orbits and an elliptical orbit was calculated by [1], following the 72-day long sighting during the return in 1826, when W. von Biela first detected it on February 27. [2] enabled the mathematically link of apparitions by [3]. Comet 3D/Biela was seen split in two during the 1845 return, with nuclei slowly moving FIG 10.5 Andromedid activity in 2021 [20]. apart. Breakup estimated by [4] to have occurred during early 1842 to mid-1843. 1852 return still showed two nuclei, but comet has been lost since. Nonsightings during favorable return in 1865e1866 suggested that comet had completely fallen apart. 3D/Biela produced meteoroids even before this breakup. Andromedids first noticed by G. W. Krafft from St. Petersburg in 1741 [5]. Chinese records of “stars fell like rain” date from December 6, 1798 [4]. Evening of 1798 December 6, Brandes [6] observed high rates of unusually slow meteors from atop a mail coach on his way to Bremen. [7] observed shower on December 7, 1830. Many visual observations on December 6 and 7, 1838 [8]. Radiant from observations during 1839e1849 at R.A. ¼ 21 , Decl. ¼ þ54 by [9]. [10] first noticed steady decreasing ascending node of 3D and predicted shower activity peaking progressively earlier. Meteor storms on November 27 in 1872 and 1885. Strong showers in 1892, 1899, and 1904. Outburst detected in 1940. First photographic orbits by [11]. Detected as annual shower in single-station video survey by [12]. CMOR radar detected outbursts in 2008 and 2011 [13]; Model of long-term evolution by [14]. Dust trail model by [15] identified 1872 storm due to 1839 and 1846 ejecta, while that in 1885 originated from the 1846 and 1852 returns. [16] showed that 1940 outburst was also due to the 1852 dust trail. Expanded model by [17] showed that 1872 and 1885 storms were not due to debris released in an aphelion breakup, but resulted from activity of fragments in 1872 and 1885. Unexpected outburst in 2021 (Fig. 10.5) reported by [20]. Name by [18], number by [19].

742

TABLE 10.2

Recorded Andromedid shower dust trail encounters.

Time (UTC)

Dr (AU)

Dao (AU)

fm (AU)

1741-12-06 00 h

e

e

e

e

e

1798-12-06 19 h 1847-12-06 20 h 1872-11-27 20:40

e e 1846 1856 1846 1856 1856 1846 1856 1852 1649 1649 e

e e 247.749 247.701 247.385 247.399 243.880 243.843 243.983 234.174 251.6 253.7 e

e e þ0.00119 þ0.00404 þ0.00032 0.00070 þ0.00428 0.00853 0.00231 0.00029 e e e

e e þ0.0222 þ0.0268 0.0060 0.0057 þ0.0211 þ0.0386 þ0.0394 þ0.0722 e e e

e e 0.249 0.287 0.275 0.211 0.214 0.090 0.189 0.043 e e e

1885-11-27 19:49 1892-11-24 02:00 1899-11-24 18:00 1940-11-15 2008-11-27 2011-12-05 2021-11-28

20:07 23 h 10:30 04:34

R.A. ( )

Decl. ( )

Vg (km/s) lo ( )

W ( )

c

ZHR (/h)

e

e

e

e

257.6

e

e

e e [15]

e 21.0 27.3

e þ54.8 þ43.8

e e e

257.8 256.3 247.713

e e e e 0.062  0.005 w3.6

“Large number” w100 w150 7400

[16] [16] [16]

[15]

26.2

þ45.3

e

247.336

0.062  0.010 3.6

6400

[16]

[15] [15]

27.2 25.2

þ40.8 þ43.0

e e

243.8 243.7

e e

e e

w300 w150

[16] [16]

[15] [13] [13] e

e 26.6 18.2 25.72  0.16

e þ44.4 þ57.5 þ44.79  0.13

e 15.9 16.2 16.9  0.3

234.2 246.0 252.75  0.10 245.856  0.004

e e e 0.081

e e 3.02 4.54  1.15

w30 w30 w50 e

[16] [13] [13] [20]

[16]

Northern antapex

Eject lo ( )

Date

December

743

References: [1] Gauss C. F., Bessel F. W. (1806) Die Monatliche Correspondenz 13, 310e313; [2] von Biela W. (1826) AN 4, 433e434; [3] Gambart J. F. A. (1926) AN 5, 125e126; [4] Marsden B. G., Sekanina Z. (1971) AJ 6, 1135e1151; [5] van Musschenbroeck P., Lulofs J. (1762) Introductio ad Philosophiam Naturalem, vol. 2, Leiden: S. and J. Luchtmans, p. 1061; [6] Benzenberg J. F., Brandes H. W. (1800) Versuch die Entfernung, die Geschwindigkeit und die Bahn der Sternschnuppen zu bestimmen. Hamburg: Friedrich Perthes, pp. 80e81; [7] Raillard F. (1839) Comptes Rendus Hebd. des Séances de l’Ac. des Sci. 8, 177e; [8] Herrick E. C. (1839) American J. of Sci. and Arts 36, 355e; [9] Heiss E. (1867) AN 69, 159e160; [10] Weiss E. (1868) AN 72, 81e102; [11] Hawkins G. S., et al. (1959) AJ 64, 183e188; [12] Rendtel J., Molau S. (2009) JIMO 37, 106e110; [13] Wiegert P. A., et al. (2013) AJ 145, 70e80; [14] Babadzhanov P. B., et al. (1991) MNRAS 253, 69e74; [15] Reznikov E. A. (1982) In: Meteornoe Veshchestvo v Mezhplanetnom Prostranstve (Meteoric Material in Interplanetary Space). Ed.: O. I. Belkovich et al., Moscow: Kazan, pp. 151e152 (in Russian); [16] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [17] Jenniskens P., Vaubaillon J. (2007) AJ 134, 1037e1045; [18] Denning W. F. (1904) Nature 71, 139e139; [19] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129; [20] Jenniskens P. (2022) eMeteorNews 7, 1e2 and 3e5.

December 4 (lo ¼ 252 )

446 DPC d December phi Cassiopeiids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.81  0.17 Episodic shower 2011, 2013, 2015/16, 2019/2020 December 2e6 (lo ¼ 250 e254 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo (  ) 252.0 19.7 þ57.1 152.5 þ44.2 16.1 0.60 þ1.30 0.48 þ1.29 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.97 0.897 0.697 17.6 218.5 252.0 110.7 0.0070 0.0537 1.33 1.39 1.04 1.39 þ0.0040 0.0012 þ0.43 0.89 þ1.00 þ0.11 w0.6/h (N ¼ 153, hr ¼ 64.1 , m(Mv ¼ 0) ¼ 0.57 g) 3.85  0.41 (s ¼ 2.46  0.11) Fragile: Component I has high He and low F ¼ 0.53 I: Hb ¼ 96.3  0.28 Mv; Hmax ¼ 88.8 þ 0.71 Mv; He ¼ 82.1 þ 1.59 Mv (N ¼ 100) F ¼ 0.53: fragile meteoroids I: r  0.52 g/cm3 (a1 ¼ 0.095 km, a2 ¼ 2.94/s), lower if fragile: low a2 w300 y [2] 3D/Biela a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.53 0.879 0.751 13.2 221.7 250.7 12.4

Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1832-Dec-03.0 TDB

eV

Brief history: Component of Andromedids (#18), different by slightly higher entry speed than annual Andromedids (see Fig. 10.6). Outburst observed on December 3e6, 2011, by CMOR radar [1] from R.A. ¼ þ18 ,  Decl. ¼ þ56 . Confirmed from low-light video observations by [2] from R.A. ¼ 252.0 , Decl. ¼ þ19.5 and Vg ¼ 16.5 km/s around lo ¼ 252.0 . [2,3] both noticed that the shower can also be divided from #18, the annual Andromedids, from a decrease in R.A. combined with a steep increase in Declination. [1] pointed out that the #446 radiant was typical of the Andromedids of the early 1800s, when the radiant was in Cassiopeia. Later, some activity from #446 was also detected in other years. Identified FIG 10.6 Finding chart of #446 in speed vs solar as debris from comet 3D by [1]. Model by [1] longitude. suggests it is debris from late 17th century. Name and number by [2].

744

Northern antapex

January

745

References: [1] Wiegert P. A., Brown P. G., Weryk R. J., Wong D. K. (2013) AJ 145, 70e80; [2] Jenniskens P., et al. (2016) Icarus 266, 384e409; [3] Molau S., et al. (2013) JIMO 41, 23e30. January 8 (lo ¼ 319 )

1171 JGC d January gamma Camelopardalids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ3.03  0.18 Annual shower January 21eFebruary 10 (lo ¼ 300 e347 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 319.2 6.0 þ72.3 112.6 þ60.5 14.4 þ1.32y 0.59y 1.62y þ0.70y 0.15y elo > 320 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.67 0.973 0.638 19.1 187.5 319.1 146.9 e V 0.0091 0.0784 2.62 6.75 12.59 6.75 1 0.0006 0.0016 0.32y 0.85y þ1.00 þ0.15 ) 1  ) lo > 320 w0.3/h (N ¼ 801, hr ¼ 40.3 , m(Mv ¼ 0) ¼ 0.70 g) 2.95  0.05 (s ¼ 2.18  0.02) I: Hb ¼ 94.7  1.41 Mv; Hmax ¼ 82.6 þ 1.01 Mv; He ¼ 76.5 þ 1.92 Mv (N ¼ 272) IIa: Hb ¼ 88.6  1.86 Mv; Hmax ¼ 79.7 þ 0.46 Mv; He ¼ 75.2 þ 1.10 Mv (N ¼ 162) III: Hb ¼ 80.7  0.79 Mv; Hmax ¼ 77.5  0.44 Mv; He ¼ 74.8  0.45 Mv (N ¼ 43) I: r w 1.8  0.4 g/cm3 (a1 ¼ 0.089 km, a2 ¼ 2.57/s) IIa: r w 2.4 g/cm3 (a1 ¼ 0.126 km, a2 ¼ 2.65/s) d possibly Na poor III: r w 3.8 g/cm3 (a1 ¼ 0.084 km, a2 ¼ 4.15/s) d possibly Na free e e

Meteoroid density:

Age: Source:

Brief history: Long duration shower (Fig. 10.7) with a large radiant drift, first detected in CAMS low-light video observations and submitted to the MDC in preparation of [1], assigned shower #711 (from R.A. ¼ 69.6 , Decl. ¼ þ78.1 and Vg ¼ 14.5 km/s around lo ¼ 309.0 ), but not published and retracted for being uncertain. Now confirmed. Shower emerges from anthelion source, then makes a large loop to higher latitudes. Perihelion increases to 1 AU limit for lo < 318.5 , then remains close to limit, before decreasing for lo > 330 . Number by [1]. Name here. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

FIG 10.7

ZHR profile (scale uncertain).

746

Northern antapex

758 VOL d Volantids

C H A P T E R

11

Southern antapex

Atlas of Earth's Meteor Showers https://doi.org/10.1016/B978-0-323-88447-1.00011-9

747

© 2024 Elsevier Inc. All rights reserved.

748

Southern antapex

April

749

April 20 (lo ¼ 30 )

137 PPU d pi Puppids

Dynamic type: Shower type: Years of outburst:

Jupiter-family comet, TJ ¼ 2.73  0.12 Episodic shower 1972: ZHR w 1.9/h [6,7] 1977: ZHR > 180  60/h, B ¼ 10  1/ , lo  32.973 [8], c  1.6 [8]; c ¼ 1.98  0.11 (s ¼ 1.74  0.06) [7] 1982: ZHR  20/h, B ¼ 8.4  2.5/ , lo < 32.556 [6,8], c ¼ 1.9 [8] April 15e30 (lo ¼ 27 e39 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 30.1 110.1 46.4 99.3 66.7 15.9 þ1.59 0.43 þ1.92 0.00 þ0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.06 1.0039 0.672 22.2 1.8 210.1 211.7 eV 0.0009 0.0232 2.33 3.19 3.30 3.19 þ0.0002 þ0.0014 þ0.07 þ0.79 þ1.00 þ1.79 N ¼ 19 (hr ¼ 43.7 , m(Mv ¼ 0) ¼ 0.70 g) c ¼ 2.41  0.28 (s ¼ 1.95  0.13); 2.0, var. [12] Component Ib has low penetration depth, like III Ib: Hb ¼ 94.3  1.30 Mv; Hmax ¼ 81.6 þ 1.87 Mv; He ¼ 74.0 þ 3.23 Mv (N ¼ 12) III: Hb ¼ 85.0  0.71 Mv; Hmax ¼ 84.2  0.99 Mv; He ¼ 80.5  0.89 Mv (N ¼ 7) Ib: r w 1.2 g/cm3 (a1 ¼ 0.283 km, a2 ¼ 3.53/s) d uncertain, low N su e

Meteoroid density: Age: Source:

751

eV

Brief history: First identified in [1] with R.A. ¼ 295.9 , Decl. ¼ -63.3 and Vg ¼ 39.2 km/s around lo ¼ 82.1 . Number and name by [1]. Reference: [1] Jenniskens P., et al. (2018) Plan. Space Sci 154, 21e29.

752

Southern antapex

July

July 10 (lo ¼ 108 )

1069 JOP d July omicron Pavonids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ1.12  0.26 Annual shower June 30eJuly 16 (lo ¼ 98 e114 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 108.0 310.8 72.5 179.7 51.6 28.9 þ2.94 0.10 þ0.26 0.40 þ0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 21.5 0.820 0.962 37.6 52.4 288.0 339.6 0.0134 0.065 1.37 2.23 4.32 2.23 þ0.0021 0.0007 þ0.30 0.30 þ1.00 þ0.70 w0.07/h (N ¼ 54, hr ¼ 43.6 , m(Mv ¼ 0) ¼ 0.17 g) c ¼ 3.07  0.09 (s ¼ 2.22  0.03) I: Hb ¼ 103.7  1.27 Mv; Hmax ¼ 94.7 þ 0.57 Mv; He ¼ 87.7 þ 2.03 Mv (N ¼ 47) I: low F ¼ 0.58, fragile meteoroids I: r w 0.55  0.20 g/cm3 (a1 ¼ 0.065 km, a2 ¼ 4.39/s) From c and s: w33,000 y e

753

eV

Brief history: Shower first detected here from 2019 to 2021 CAMS observations of southern hemisphere showers. July 11 (lo ¼ 109 )

1144 JKV d July kappa Velids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.94  0.24 Annual shower July 5e21 (lo ¼ 103 e119 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 109.2 140.5 55.6 70.4 63.2 14.7 þ0.51 0.13 0.39 þ0.10 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.80 1.0126 0.639 20.5 351.8 289.2 280.9 eV 0.0031 0.0780 1.79 2.64 3.86 2.64 0.0002 þ0.0029 þ0.02 0.15 þ1.00 þ0.85 w0.2/h (N ¼ 39, hr ¼ 24.9 , m(Mv ¼ 0) ¼ 0.69 g) c ¼ 2.85  0.16 (s ¼ 2.14  0.06) Ib: Hb ¼ 93.4  0.64 Mv; Hmax ¼ 81.7 þ 1.93 Mv; He ¼ 75.7 þ 2.92 Mv (N ¼ 29) IIb: Hb ¼ 84.3  1.55 Mv; Hmax ¼ 80.0  0.50 Mv; He ¼ 73.7 þ 0.34 Mv (N ¼ 9) Ib: normal F ¼ 0.66; IIb, like III with F ¼ 0.41 Ib: r w 2.0 g/cm3 (a1 ¼ 0.268 km, a2 ¼ 1.62/s) d uncertain due to low N IIb: r w 2.1 g/cm3 (a1 ¼ 0.049 km, a2 ¼ 6.00/s) d possibly Na poor/free e e

Lightcurve shape: Meteoroid density: Age: Source:

Brief history: Shower first detected here from 2019 to 2021 CAMS observations of southern hemisphere showers.

754

Southern antapex

755

September

Sep. 26 (lo ¼ 183 )

1089 CTS d September tau Cetids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ0.89  0.37 Annual shower September 13eOctober 3 (lo ¼ 170 e190 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 183.0 22.0 17.4 190.5 24.5 34.2 þ0.74 þ0.05 0.27 0.23 0.16 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 26.9 0.446 0.997 30.4 97.5 3.0 99.5 eV 0.0129 0.031 1.22 1.37 4.88 1.37 þ0.0060 0.0002 0.09 0.71 þ1.00 þ0.29 0.02/h (N ¼ 60, hr ¼ 38.5 , m(Mv ¼ 0) ¼ 0.11 g) c ¼ 2.47  0.24 (s ¼ 1.98  0.11) Ib: Hb ¼ 103.8  0.68 Mv; Hmax ¼ 95.9 þ 0.77 Mv; He ¼ 91.3 þ 0.70 Mv (N ¼ 36) Ib: r w 0.65 g/cm3 (a1 ¼ 0.087 km, a2 ¼ 6.50/s) d uncertain due to low N From c and s: w13,000 y e

Brief history: First identified here. Aug. 16 (lo ¼ 142 )

198 BHY d beta Hydrusids

Dynamic type: Shower type: Year of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed: Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Age: Source:

Jupiter-family comet shower, TJ ¼ þ1.91  0.33 Episodic shower 1985 August 11e17, 1985 (lo ¼ 138 e144 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 142.3 23.2 80.9 149.3 68.0 21.8 þ2.15 þ0.84 þ1.30 þ0.00 þ0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 5.79 0.974 0.829 31.2 23.6 322.3 347.2 0.0093 0.067 0.70 3.20 2.57 3.20 þ0.0016 0.0053 þ0.16 þ0.52 1.00 1.52 (3.25) 0.966 0.703 35.0 27.3 323.8 351.1 N ¼ 4 (hr ¼ 42.0 , m(Mv ¼ 0) ¼ 0.31 g) 1985: lo ¼ 143.794, ZHR ¼ 80  20, W ¼ 0.021  0.004 1985: c ¼ 2.1 [2e3] IIa: Hb ¼ 95.4  0.32 Mv; Hmax ¼ 83.7 þ 0.67 Mv; He ¼ 75.3 þ 0.63 Mv (N ¼ 3) IIa: F ¼ 0.58: fragile e e

[no map shown]

eV e [1]

Brief history: Significant outburst on night of August 16/17, 1985 [1e3]. Meteors were predominantly bright, yelloweorange in color, and moved slowly in long trails. Noticed by public, who alerted police and media. The plotted radiant was at R.A. ¼ 23 , Decl. ¼ 76 (B1950) and estimated speed 18  4 km/s. Rates by experienced NAPO-MS observers B. Macauley at Bickley, J. Tame and S. Evans at Kalamunda, P. Rawlings at Belmont, and J.-A. Borrows and M. Clay from Byford, all in Western Australia. Predicted outbursts in 2019 and 2020 (assuming that the 1985 outburst was from crossing the 1-revolution dust trail of a long-period comet [1]) were not observed. No clear detection in recent video data. Data based on small grouping of four possible b-Hydrusids in 2019e2021 video data. References: [1] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 346e347; [2] Wood J. (1986) NAPO-MS Bull. 121, Perth: NAPO, issued May; [3] Wood J. (1986) Radiant, Journal of the DMS 8, 75e75.

756

Southern antapex

757

September

Sep. 29 (lo ¼ 186 )

1130 ARD d Arids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Date of peak activity: Number observed: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2014-Nov-08.0 TDB

Jupiter-family comet, TJ ¼ 2.70  0.78 Episodic shower 2021 (September 27e30, October 7) September 26e30 þ October 7 (lo ¼ 183.9 e187.2 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 185.9 261.5 57.5 78.8 34.1 10.3 0.73 þ1.19 1.61 þ1.15 0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.32 1.0001 0.699 8.9 355.5 5.9 1.4 eV 0.0015 0.108 0.80 0.58 0.45 0.58 0.0008 þ0.0023 0.32 0.88 þ1.00 þ0.12 September 29 (lo ¼ 185.92 ) N ¼ 97 (hr ¼ 44.0 , m(Mv ¼ 0) ¼ 1.15 g) c ¼ 2.57  0.08 (s ¼ 2.03  0.03) Ib: Hb ¼ 91.9  0.85 Mv; Hmax ¼ 81.5 þ 1.73 Mv; He ¼ 78.0 þ 1.80 Mv (N ¼ 95) Ib: F ¼ 0.75 Ib: r w 1.8  0.4 g/cm3 (a1 ¼ 0.223 km, a2 ¼ 1.59/s) 7e26 y: trails from 1995 (September 29, 2021); 2008 (October 7); 2014 (October 7) 15P/Finlay a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.49 0.976 0.720 6.80 347.6 13.8 1.4

Brief history: Despite earlier searches [1], no meteors from 15P until late September 2021. No trail crossings since 1965, but for 2021 a number of dust trail crossings were predicted ([2], Table 6c). Because of the small orbit inclination, these showers were expected to be broad, perhaps lasting longer than a day. More recent predictions [2e6,9] given in Table below. Comet outbursts on 2014 Dec. 15.4e16.0 UT and 2015 Jan. 15.6e15.7 UT [8], with [5,9] predicting separate encounters in 2021. 2014 debris detected by CAMS video [7] and SAAMER radar (peak ZHR w 120/h) [7]. Further outbursts predicted for 2027 Oct 23 (22:24 UT), 2028 (Oct 6 20:57), strong in 2034 (Oct 4 14:14), 2040 (Oct 19 01:15), 2047 (Oct 1 02:22 and Oct 7 20:49) [3]. Name and number by [7]. Encounter 2021 (UTC)

Eject

lo ( )

R.A. ( )

Decl. ( )

Vg (km/s)

ZHR (/h)

c

09/27 06:14 09/27 13:58e16:22 Obs: 09/28 18:58 09/29 02:30e04:17 09/29 08:35 Obs: 10/07 03:55 Obs: 10/07 01:19 10/07 01:10 10/07 00:35 Obs:

1988 ” ” 1995 ” ” ” 2008 ” 2014 ” ” ”

184.067 184.432 184.35  0.18 185.569 185.914 186.072 186.10  0.07 193.728 193.78  0.01 193.698 193.704 193.674 193.67  0.01

264.1 261.1 261.6  0.7 261.6 261.6 260.8  0.9 261.0  1.0 254.5  1.0 256.0  0.6 255.8 255.7 255.5  0.8 255.9  0.7

60.5 60.5 60.9  0.4 57.7 57.7 57.4  0.5 57.3  0.3 48.3  0.2 48.7  0.3 48.3 48.4 48.3  0.6 48.4  0.3

11.0 11.0 11.2  0.4 10.82 10.8 10.807 10.5  0.2 10.730 10.7  0.4 10.7 10.7 10.752 10.5  0.3

e 5e100 N ¼ 12 e 50e500 13 N ¼ 38 43 N ¼ 12 5e50 e 178 N ¼ 23

e 2.5 2.52  0.20 e 2.5 2.5 2.28  0.11 2.5 2.37  0.45 2.5 e 2.5 2.70  0.12

[2] [3] [2] [3] [6] [6] [3] [4] [6]

References: [1] Beech M., Nikolova S., Jones J. (1999) MNRAS 310, 168e174; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [3] Maslov M. (2009) website: http://feraj.ru/Radiants/Predictions/1901-2100eng/Finlayids1901-2100predeng.html (last accessed 2021 September 30); [4] Sato M. (2009) https://groups.yahoo.com/neo/groups/meteorobs/ conversations/messages/44030 (Deleted December 2020); [5] Ye Q.-Z., et al. (2015) ApJ 814, 79e88; [6] Vaubaillon J., et al. (2020) JIMO 48, 29e35; [7] Jenniskens P., et al. (2021) eMeteorNews 6, 531e533 and 534e535; [8] Ishiguro M., et al. (2016) AJ 152, 169e183; [9] Ye Q. (2021) The Astronomer’s Telegram, No. 14947 (issued October 2021).

758

Southern antapex

December

Dec. 2 (lo ¼ 250 )

254 PHO d Phoenicids

Dynamic type: Shower type: Years of outbursts:

Jupiter-family comet, TJ ¼ þ3.17  0.25 Episodic shower 1887: lo ¼ w252.6 , ZHR w50 /h; R.A. ¼ 24 , Decl. ¼ 55 [6] 1933: lo ¼ w253.6?, R.A. ¼ 23 , Decl. ¼ 57 [6] 1956: lo ¼ w253.14 , 50  30/h, W ¼ 0.46  0.12, (15 , 58 ), c ¼ 2.9 [6] 1972: lo ¼ w252.9 , ZHR ¼ 20/h, R.A. ¼ 20 , Decl. ¼ 53 [6] 2014: lo ¼ w249.6 , ZHR ¼ 16  5 [14,16], R.A. ¼ 7.4 , Decl. ¼ 27.8 December 1e2 (lo ¼ 249 e250 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 249.6 7.4 27.8 105.9 28.0 8.9 þ0.08 1.07 1.46 0.98y 0.15 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.51 0.981 0.609 6.5 9.7 69.6 78.7 0.0011 0.051 0.60 1.11 0.31 1.11 þ0.0020 0.0035 þ0.19 0.99 þ1.00 þ0.01 2014: N ¼ 5 (hr ¼ 61.1 , m(Mv ¼ 0) ¼ 1.36 g) Annual: c ¼ 2.8 [15] 1956: 137 y [1]; 2014: 84e100 y [2]; core of stream (dU < du) #1046 289P/Blanpain a (AU) q (AU e i ( ) u ( ) U ( ) P ( ) 3.05 0.959 0.685 5.9 9.8 68.9 78.7

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Magn. distribution index: Age: Related showers: Source: Orbital elements (J2000.0) Epoch 2019-Aug-04.0 TDB

759

e 2014 eV (2014)

Brief history: Possible prior sightings in 1887 (V. Williams of Parrammatta, NSW, Australia: “bright, slow yellow meteors with long paths”) and 1933 (Capt. Murray, on boat in South Pacific Ocean: “a large number of bright meteors coming from a point near the star Achernar”), but Phoenicids were first well documented during an outburst on December 5, 1956, observed from New Zealand (R. Lynch), Australia, South Africa, and Japan [1e3,18,19]. [2] reported ZHR w 300/h. [3], director of the Meteor Section of ASSA, reported ZHR w 100/h during first 2 h of observing period and radiant at R.A. ¼ 15 , Decl. ¼ 54 . University of Adelaide radar had R.A. ¼ 15  2 , Decl. ¼ 55  3 [4], despite difficulty detecting slow meteors [17]. Analysis and ZHR curve by [5,6]. Weakly active with faint meteors in later years. Outburst of December 4, 1972, was observed by M. Buhagiar and S. Dimmitt. Association with 289P by [19]. Comet D/1910 W1 (¼289P) was long lost until linked to 2003 WY25 by [7] (story in [8]) and weak cometary activity was detected from 2003 WY25 by [9]. Significant PHO activity seen in 2013 [9]. Model by [10] found that this dust may be associated with the breakup of 289P just before its sighting in 1819. [11] linked 1956 outburst to possible activity in returns between 1760 and 1814, in agreement. Possible returns predicted in 2008, 2014 and 2019 by [12]. 2014 activity observed with ZHR ¼ 16  5 [13,14] and shown here as detection in the NASA and SOMN allsky video cameras (N ¼ 5) reported by [14] and by SonotaCo low-light video observations (N ¼ 5). 2008 and 2019 activity was closer to the ecliptic plane and is called shower #1046. Drifts were calculated by including shower #1046. Name by [4], number by [8]. References: [1] Shain C. A. (1957) The Observatory 77, 27e28; [2] Huruhata M., Nakamura J. (1957) Tokyo Astron. Bull., 2nd Ser., No. 99; [3] Venter S. C. (1957) MNASSA 16, 6e7; [4] Weiss A. A. (1958) AuJPh 11, 113e117; [5] Ridley H. B. (1962) JBAA 72, 266e268; [6] Jenniskens P. (1995) AA 295, 206e235; [7] Foglia S., et al. (2005) IAU Circ. 8485. Ed.: D. W. E. Green, Cambridge: CBAT, 1 pp.; [8] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, 790 pp; [9] Jewitt D. (2006) AJ 131, 2327_2331; [9] Ye Q., Clark D. L. (2019) ApJ Lett. 878, L34eL40; [10] Jenniskens P., Lyytinen E. (2005) AJ 130, 1286e1290; [11] Watanabe J.-I., Sato M., Kasuga T. (2005) PASJ 57, L45eL49; [12] Sato M., Watanabe J.-I. (2010) PASJ 62, 509e513; [13] Sato M. (2014) Phoenicids 2014. Online pamphlet, 4 pp; [14] Sato M., Watanabe J.-I., Tuschiya C., Moorhead A. V., Moser D. E., Brown P. G., Cooke W. J. (2014) PSS 143, 132e137; [15] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25; [16] Roggemans P., Johannink C., Martin P. (2019) eMeteorNews 1, 4e10; [17] McBeath A. (2003) JIMO 31, 148e152; [18] Wood J. (1981) WAMS Bull. 157, 1e7; [19] Ridley H. B. (1957) BAA Circular, No. 382.

760

Southern antapex

761

January

Jan. 7 (lo ¼ 286 )

707 BPX d beta Pyxidids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, toroidal shower, TJ ¼ þ0.85  0.35 Annual shower December 27eJanuary 13 (lo ¼ 275 e292 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 286.0 132.5 35.8 224.5 50.6 44.9 þ0.78 0.34 þ0.13 0.06 þ0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 10.0 0.742 0.928 73.1 60.6 106.0 166.5 eV 0.0313 0.0786 2.64 4.90 3.88 4.90 þ0.0015 0.0008 þ0.07 0.18 þ1.00 þ0.82 w0.2/h (N ¼ 180, hr ¼ 55.6 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.76  0.08 (s ¼ 2.10  0.03) Component IIb has low He (ke < 79), like III: IIa: Hb ¼ 104.5  0.74 Mv; Hmax ¼ 93.9 þ 1.94 Mv; He ¼ 88.5 þ 2.36 Mv (N ¼ 86) IIb: Hb ¼ 96.2  0.42 Mv; Hmax ¼ 91.0 þ 0.44 Mv; He ¼ 85.5 þ 0.96 Mv (N ¼ 63) IIa: r w 0.91 g/cm3 (a1 ¼ 0.060 km, a2 ¼ 4.93/s) IIb: r w 1.9 g/cm3 (a1 ¼ 0.050 km, a2 ¼ 9.59/s) d possibly Na poor/free

Meteoroid density:

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed:

January 2e15 (lo ¼ 282 e295 ) R.A. ( ) Decl. ( ) lo (  ) 288.8 134.9 38.0 þ0.84 0.45 a (AU) q (AU) e 2.77 0.735 0.758 0.0299 0.144 þ0.0012 0.0114 N ¼ 507

Age: Source:

From c and s: w29,000 y e

l ( ) 226.1 þ0.30 i ( ) 69.4 4.19 0.13

b ( ) 51.8 0.10 u ( ) 65.6 7.87 þ0.18

Vg (km/s) 41.3 0.20 U ( ) 108.8 2.89 þ1.00

P ( ) 174.4 7.87 þ1.18

e R[S]

Brief history: First described by [1] from radiant at R.A. ¼ 133.0 , Decl. ¼ 36.3 and Vg ¼ 45.7 km/s around lo ¼ 288.0 . Shower reported here based on SAAMER radar data described in [2]. Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409; [2] Bruzzone J. S., et al. (2020) PSS 188, article id. 104936.

762

Southern antapex

February

763

Feb. 12 (lo ¼ 324 )

1032 FHY d February Hydrids

Dynamic type: Shower type: Year of outburst: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2022-Aug-09.0 TDB Source: Epoch 2008-Mar-01.0 TDB

Jupiter-family comet, TJ ¼ þ2.93  0.14 Episodic shower 2013, 2018, 2023 February 9e13 (lo ¼ 321 e325 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 323.9 123.6 þ1.9 161.7 17.5 16.4 e2018 þ0.67 0.53 0.19 0.37 0.17 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.70 0.811 0.699 8.0 55.3 143.9 199.0 eV 0.0060 0.048 0.38 0.44 1.19 0.44 þ0.0032 þ0.0069 þ0.09 0.34 þ1.00 þ0.66 w0.06/h (N ¼ 47, hr ¼ 44.5 , m(Mv ¼ 0) ¼ 0.56 g) c ¼ 3.05  0.41 (s ¼ 2.21  0.14) I: Hb ¼ 95.8  0.85 Mv; Hmax ¼ 82.4 þ 1.97 Mv; He ¼ 76.8 þ 2.50 Mv (N ¼ 44) I: r w 1.3 g/cm3 (a1 ¼ 0.138 km, a2 ¼ 1.72/s) e 2022 EH1 d uncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.66 0.874 0.671 9.0 46.8 162.2 209.0 2008 DV22 d uncertain 2.69 0.986 0.634 11.0 56.2 153.1 209.3

Brief history: [1] reported a weak outburst in CAMS low-light video observations with R.A. ¼ 123.92  1.18 , Decl. ¼ þ1.48  1.15 and Vg ¼ 16.40  1.28 km/s during 2018 February 9e17. Outbursts may return every 5 years. Detected number in 2007e2023 for each year: 0, 0, 0, 0, 0, 0, 3 (2013), 0, 1, 0, 0, 12 (2018), 0, 0, 2, 1, 28 (2023). A D-criterion search of SonotaCo, EDMOND, and CAMS datasets by [2] extracted meteors over a wider radiant area, with highest rates in 2013. Possible sources identified here have TJ ¼ 3.00 and 3.02, respectively, and can be asteroid interlopers. Name and number by [1]. References: [1] Jenniskens P., Johannink C., Moskovitz N. (2018) JIMO 46, 85e86; [2] Roggemans P., Cambell-Burns P. (2018) eMeteorNews 3, 128e133.

764

Southern antapex

40 ZCY d zeta Cygnids

C H A P T E R

12

North and south poles

Atlas of Earth's Meteor Showers https://doi.org/10.1016/B978-0-323-88447-1.00007-7

765

© 2024 Elsevier Inc. All rights reserved.

766

North and south poles

767

March

March 13 (lo ¼ 352 )

108 BTU d beta Tucanids

Dynamic type: Shower type: Years of outbursts:

Meteoroid density:

Jupiter family comet, TJ ¼ þ2.23  0.31 Episodic shower 2018: lo ¼ 352.41  0.05 , N ¼ 16; 2019: lo ¼ 352.41  0.06 , N ¼ 9 eR[S] 2020: lo ¼ 352.40  0.08 [1]; 2021: lo ¼ 352.26  0.05 , FWHM ¼ 0.5 [2] March 12e14 (lo ¼ 351.6 e352.6 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 352.26 62.1 77.4 304.3 76.8 30.6 e V (2021) þ1.54 þ0.25 1.82 0.22 þ0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.86 0.977 0.658 51.0 344.0 172.3 156.0 eV 0.0043 0.058 1.48 2.32 0.24 2.32 þ0.0019 þ0.0085 þ0.44 þ1.13 þ1.00 þ2.13 var. (N ¼ 26 in 2021 e V; hr ¼ 30.8 , m(Mv ¼ 0) ¼ 0.14 g) c ¼ 2.48  0.23 (s ¼ 1.99  0.10) Component IIa has low end height, Ke < 79: IIa: Hb ¼ 98.2  0.94 Mv; Hmax ¼ 86.5 þ 1.63 Mv; He ¼ 81.6 þ 2.37 Mv (N ¼ 33) IIa: r w 1.8 g/cm3 (a1 ¼ 0.175 km, a2 ¼ 2.45/s) duncertain due to low N

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Number observed:

March 12e13 (lo ¼ 351.9 e352.9 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 352.42 58.9 76.5 309.4 þ2.71 0.77 5.24 a (AU) q (AU) e i ( ) 2.43 0.973 0.598 48.2 0.0079 0.071 2.07 þ0.0019 0.0228 þ0.48 3.20 0.960 0.700 50.77 N ¼ 56

b ( ) 76.2 0.17 u ( ) 340.7 3.81 þ0.43 345.31

Vg (km/s) 28.7 þ0.05 U ( ) 172.48 0.24 þ1.00 172.20

P ( ) 153.2 3.81 þ1.43 157.5

e R[4]

Age: Source: Orbital elements (J2000.0) Epoch 2020-Dec-17.0 TDB

e; Earth passing through core of stream (sU < su) (248590) 2006 CS a (AU) q (AU) e i ( ) u ( ) 2.91 0.880 0.698 52.3 346.4

U ( ) 172.4

P ( ) 158.8

[6]

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

FIG 12.1

ZHR profile (scale uncertain).

(2018e2020)

e R[S]

Brief history: First orbital elements measured by Adelaide radar in 1969 [1,2]. Shower number 3.04 with 11 measured trajectories had a radiant at R.A. ¼ 51 , Decl. ¼ 81 , VN ¼ 34 km/s (B1950.0). Average activity was centered on March 18, with radar in operation March 16e22. Gatrell [1] remarked on stark difference in entry speed with nearby shower 3.05 (IAU #130). Strong detection in SAAMER radar observations in 2020, JFC-type orbit [4]. Confirmed in video data when shower returned in 2021 [5]. Activity curve shown in Fig. 12.1. Yearly number of CAMS triangulated beta Tucanids starting in 2020: 14, 26, 10, 7. Source identified as 2006 CS by [4]. Name and number assigned by [3].

References: [1] Gartrell G. (1972) Publ. Astron. Soc. Australia 2, 89e90; [2] Gartrell G., Elford W. G. (1975) AuJPh 28, 591e620; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 701; [4] Janches D., et al. (2020) ApJ Let. 895, L25eL31; [5] Jenniskens P. (2021) eMeteorNews 6, 330e331; [6] Website: https://cneos.jpl. nasa.gov/ (Passadena: JPL/Caltech, last accessed October 2021).

768

North and south poles

March

March 12 (lo ¼ 351 )

346 XHE d x Herculids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, toroidal, TJ ¼ þ2.51  0.25 Annual shower March 4e14 (lo ¼ 343 e353 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 351.2 253.7 þ49.2 245.2 þ70.6 34.7 þ0.91 0.28 þ0.06 þ0.15 þ0.13 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.86 0.977 0.658 59.7 196.2 351.2 186.7 0.0037 0.140 2.53 2.18 1.56 2.18 þ0.0011 0.0063 þ0.06 0.39 þ1.00 þ0.61 w0.2/h (N ¼ 174, hr ¼ 63.7 , m(Mv ¼ 0) ¼ 0.11 g) c ¼ 2.38  0.22 (s ¼ 1.94  0.10); rich in bright meteors [4] Component Ib meteoroids penetrate deep, KE < 82: Ib: Hb ¼ 102.0  0.45 Mv; Hmax ¼ 89.1 þ 2.62 Mv; He ¼ 83.9 þ 3.15 Mv (N ¼ 21) IIa: Hb ¼ 98.6  1.09 Mv; Hmax ¼ 87.5 þ 1.27 Mv; He ¼ 81.8 þ 2.15 Mv (N ¼ 57) Ib: Perhaps fragile, low a2 (but low N); wide dispersion in altitudes IIa: r w 1.6 g/cm3 (a1 ¼ 0.063 km, a2 ¼ 6.77/s) e e

Meteoroid density: Age: Source:

769

eV

Brief history: First identified by [1] from single-station IMO Video Meteor Network video observations from R.A. ¼ 254 , Decl. ¼ þ48 and Vg ¼ 36 km/s around lo ¼ 352 . One photographed orbit in 1954 and six Harvard Meteor Project radar-detected orbits in 1961e1969 may belong to this stream [4]. Confirmed from triangulated observations by [2,3]. There is a nearby shower over a range of later solar longitude. Name and number by [1]. References: [1] Molau S., Kac J. (2009) JIMO 37, 92e93; [2] Greaves J. (2012) JIMO 40, 53e58; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Roggemans P., CambellBurns P. (2018) eMeteorNews 3, 120e127. March 16 (lo ¼ 356 )

1176 SSH d 77 Herculids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.60  0.33 Annual shower March 10e20 (lo ¼ 350 e360 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 355.9 261.6 þ47.9 256.7 þ70.8 35.4 þ0.84 0.00 þ0.68 þ0.09 þ0.10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.75 0.990 0.640 60.7 188.1 356.2 183.8 eV 0.0028 0.270 3.71 2.81 2.42 2.81 þ0.0009 þ0.0030 0.01 0.67 þ1.00 þ0.33 w0.2/h (N ¼ 118, hr ¼ 52.5 , m(Mv ¼ 0) ¼ 0.10 g) c ¼ 1.84  0.08 (s ¼ 1.66  0.03) Component IIb has low He, KE < 79, like III: IIa: Hb ¼ 99.6  1.07 Mv; Hmax ¼ 89.7 þ 0.79 Mv; He ¼ 84.6 þ 1.19 Mv (N ¼ 34) IIb: Hb ¼ 93.8  1.47 Mv; Hmax ¼ 85.7 þ 0.71 Mv; He ¼ 82.6 þ 0.73 Mv (N ¼ 46) IIa: r w 0.52 g/cm3 (a1 ¼ 0.241 km, a2 ¼ 3.10/s) IIb: r w 1.3 g/cm3 (a1 ¼ 0.114 km, a2 ¼ 5.11/s) dpossibly Na poor/free e e

Meteoroid density: Age: Source:

Brief history: First identified here.

770

North and south poles

March

771

772

North and south poles

773

April

April 5 (lo ¼ 15 )

1106 GAD d gamma Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 1954-Mar-29.0 TDB

Mellish-type shower, TJ ¼ þ0.91  0.48 Annual shower April 4e6 (lo ¼ 14.5 e16.1 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 15.2 275.5 þ53.8 269.3 þ1.37 þ0.07 þ2.26 a (AU) q (AU) e i ( ) 18.7 1.0003 0.946 58.8 0.0002 0.112 1.61 þ0.0002 þ0.0339 þ0.17 w0.2/h (N ¼ 34, hr ¼ 36.7 , m(Mv ¼ 0) ¼ 0.09 g) c ¼ 2.23  0.30 (s ¼ 1.87  0.14) Ia: Hb ¼ 110.2  1.53 Mv; Hmax ¼ 101.7  0.51 Mv; Ia: low F ¼ 0.42, fragile meteoroids Ia: r w 0.32 g/cm3 (a1 ¼ 0.105 km, a2 ¼ 3.71/s) From c and s: w14,000 y C/1953 T1 (Abell) a (AU) q (AU) e i ( ) N 0.970 1.000 53.2

b ( ) þ77.0 0.09 u ( ) 178.9 1.02 þ0.16

Vg (km/s) 36.6 0.25 U ( ) 15.2 0.43 þ1.00

P ( ) 194.3 1.02 þ1.16

eV

He ¼ 91.7 þ 2.49 Mv (N ¼ 17) duncertain due to low N u ( ) 194.4

U ( ) 3.0

duncertain P ( ) 197.4

Brief history: Shower first reported by [1] from 20 triangulated orbits by the Global Meteor Network in 2021 from R.A. ¼ 275.7 , Decl. ¼ þ53.9 and Vg ¼ 36.0 km/s around lo ¼ 275.7 . Independently discovered during this work. The orbit of hyperbolic (e ¼ 1.00081  0.00004) comet C/1953 T1 is sufficiently different from that of the meteoroids that this comet was not deemed a viable candidate by [1]. Name and number by [1]. References: [1] Vida D., Segon D. (2021) eMeteorNews 6, 337e339. April 5 (lo ¼ 15 )

1051 AKC d April kappa Cygnids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.95  0.34 Annual shower March 3e27 (lo ¼ 8 e22 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 14.9 287.2 þ54.8 299.3 þ75.4 36.3 þ0.39 þ0.06 0.27 0.08 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 20.6 0.987 0.952 58.1 166.5 14.9 181.6 eV 0.0060 0.085 1.61 2.99 3.29 2.99 þ0.0002 þ0.0008 þ0.15 0.02 þ1.00 þ0.99 w0.2/h (N ¼ 120, hr ¼ 43.6 , m(Mv ¼ 0) ¼ 0.09 g) c ¼ 3.28  0.20 (s ¼ 2.29  0.06) Component IIb has low He, Ke < 79, and F like III: Ib: Hb ¼ 104.0  0.80 Mv; Hmax ¼ 95.2 þ 1.15 Mv; He ¼ 90.5 þ 1.45 Mv (N ¼ 62) IIb: Hb ¼ 93.7 þ 0.13 Mv; Hmax ¼ 88.9 þ 0.56 Mv; He ¼ 83.5 þ 1.07 Mv (N ¼ 11) Ib: r w 0.59 g/cm3 (a1 ¼ 0.239 km, a2 ¼ 3.50/s) IIb: r w 2.7 g/cm3 (a1 ¼ 0.036 km, a2 ¼ 8.94/s) dpossibly Na poor (low N) From c and s: w43,000 y e

Meteoroid density: Age: Source:

Brief history: First reported here.

774

North and south poles

April

775

April 22 (lo ¼ 31 )

581 NHE d 90 Herculids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.78  0.26 Annual shower March 25eMay 1 (lo ¼ 4 e41 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 31.3 262.5 þ40.0 225.4 þ63.0 40.3 þ0.19 0.46 0.53 0.43 þ0.10 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.6 0.914 0.949 65.1 215.3 31.3 246.6 eV 0.0198 0.058 2.94 4.63 8.92 4.63 1 0.0042y þ0.0031 þ0.07 þ0.87y þ1.00 þ1.87 ) 1 ) lo > 15 w0.3/h (N ¼ 748, hr ¼ 64.7 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.80  0.05 (s ¼ 2.12  0.02) Ib: Hb ¼ 105.2  0.96 Mv; Hmax ¼ 96.1 þ 1.07 Mv; He ¼ 91.3 þ 1.51 Mv (N ¼ 584) II: Hb ¼ 99.2  1.69 Mv; Hmax ¼ 92.3  0.33 Mv; He ¼ 87.2  0.23 Mv (N ¼ 43) III: Hb ¼ 92.1  1.13 Mv; Hmax ¼ 85.5 þ 0.86 Mv; He ¼ 81.6 þ 0.76 Mv (N ¼ 28) Ib: r w 0.55  0.28 g/cm3 (a1 ¼ 0.086 km, a2 ¼ 4.79/s) dNa chondritic II: r w 1.9 g/cm3 (a1 ¼ 0.031 km, a2 ¼ 6.57/s) dPossibly Na poor III: r w 1.3 g/cm3 (a1 ¼ 0.280 km, a2 ¼ 5.50/s) dNa free Mg1.34 Fe0.70 Na0.026 (N ¼ 4) From c: w36,000 y, dU > du: Significantly spread in node C/1861 G1 (Thatcher) a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 55.7 0.921 0.983 79.8 213.4 31.9 245.1

Meteoroid density:

Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1861-May-25.0 TDB

Brief history: Narrower in b than in l, b change not linear prior to lo ¼ 16 . First reported from Croatian Meteor Network data by [1] from R.A. ¼ 264.3 , Decl. ¼ þ40.3 and Vg ¼ 39.0 km/s around lo ¼ 38 . Radiant just north-west of that of the April Lyrids and [2] speculates on origin from a fragment of C/1861 G1. References: [1] Gural P., et al. (2014) JIMO 42, 132e138; [2] Hajduková M., Neslusan L. (2021) PSS 203, id. 105246. April 27 (lo ¼ 37 )

653 RLY d R Lyrids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Spectroscopy: Age:

Mellish-type shower, TJ ¼ þ0.76  0.26 Annual shower April 20eMay 5 (lo ¼ 30 e45 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 37.4 287.0 þ49.6 267.8 þ71.0 39.6 þ0.83 þ0.05 þ0.61 0.14 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 14.0 1.006 0.928 65.8 180.3 37.4 217.6 0.0007 0.146 3.43 2.45 3.54 2.45 þ0.0001 0.0005 þ0.04 0.01 þ1.00 þ0.99 w0.06/h (N ¼ 180, hr ¼ 59.2 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 2.04  0.13 (s ¼ 1.78  0.07) Ib: Hb ¼ 104.4  0.91 Mv; Hmax ¼ 95.0 þ 0.85 Mv; He ¼ 90.2 þ 1.36 Mv (N ¼ 95) Ib: r w 0.78 g/cm3 (a1 ¼ 0.083 km, a2 ¼ 6.39/s) Mg0.86 Fe0.95 Na0.060 (N ¼ 1), chondritic From c: w8000 y, young stream with significant radiant spread

eV

Brief history: Separate from #854 PCY (psi Cygnids) in Plo diagram. First reported by [1] from CAMS and SonotaCo data from R.A. ¼ 280.4 , Decl. ¼ þ47.6 and Vg ¼ 40.1 km/s around lo ¼ 32 . Name and number by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 384e409.

776

North and south poles

April

777

778

North and south poles

779

June

June 23 (lo ¼ 93 )

88 ODR d omicron Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ1.29  0.28 Annual shower June 1eJuly 11 (lo ¼ 71 e108 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 93.0 253.1 þ54.6 136.2 þ75.4 24.3 þ0.01 þ0.13 1.24 þ0.10 0.06 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.7 1.006 0.942 35.1 191.8 93.1 285.2 0.0052 0.077 1.55 2.27 9.18 2.27 þ0.0008 þ0.0006 0.11 0.36 þ1.00 þ0.62 w0.03/h (N ¼ 275, hr ¼ 66.2 , m(Mv ¼ 0) ¼ 0.25 g) c ¼ 1.98  0.11 (s ¼ 1.74  0.06) Ib: Hb ¼ 99.2  1.14 Mv; Hmax ¼ 89.9 þ 0.92 Mv; He ¼ 85.5 þ 1.35 Mv (N ¼ 154) Ib: r w 0.61  0.13 g/cm3 (a1 ¼ 0.074 km, a2 ¼ 4.62/s) From c: w2500 y, large dispersion: Rapid radiant motion of young stream e

eV

Brief history: Stands out from sporadic background by significantly higher average speed. First video detection by [1] with R.A. ¼ 259.3 , Decl. ¼ þ55.8 and Vg ¼ 19.6 km/s around lo ¼ 104.4 . Name and number taken from [2], but provenance in error. “o-Draconids” first identified in photographic observations by [3] from R.A. ¼ 271 , Decl. ¼ þ59 , Vg ¼ 28.6 km/ s during lo ¼ 104e122 (N ¼ 3), linked to C/1919 Q2 (Metcalf), with theoretical radiant R.A. ¼ 282 , Decl. ¼ þ65 , Vg ¼ 29.0 km/s at lo ¼ 122 . Detected by Harvard Radio Meteor Project radar [4] with R.A. ¼ 285 , Decl. ¼ þ61.3 , Vg ¼ 28.6 km/s on lo ¼ 115.5 (N ¼ 14). Not confirmed here. [2] assigned number 88 to these detections, but that number represented two unrelated meteors by [5]. So, number and name by [1]. References: [1] Jenniskens P., et al. (2016) Icarus 266, 355e370; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 716; [3] Cook A. F., et al. (1973) SCoA 15, 1e5; [4] Sekanina Z. (1976) Icarus 27, 265e321; [5] Jacchia L. G., Whipple F. L. (1961) SCoA 4, 97e129. June 4 (lo ¼ 74 )

1178 RDR d rho Draconids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.84  0.35 Annual shower, perhaps with episodic outbursts 2020?: lo ¼ 73.92  0.11 June 3e5 (lo ¼ 73 e75 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 73.8 297.7 þ66.3 297.5 þ79.0 34.8 þ1.29 þ0.23 þ0.99 0.45 þ0.34 a (AU) q (AU) e i ( ) u ( ) U ( ) 54.0 1.0081 0.981 55.6 170.8 73.82 0.0010 0.125 1.55 0.85 0.24 0.0007 þ0.0041 þ0.52 0.60 þ1.00 w0.8/h (N ¼ 52, hr ¼ 55.3 , m(Mv ¼ 0) ¼ 0.11 g) c ¼ 2.07  0.11 (s ¼ 1.79  0.06) Fragile: I component has high He: I: Hb ¼ 105.8  0.61 Mv; Hmax ¼ 98.5 þ 0.75 Mv; He ¼ 92.7 þ 1.44 Mv (N ¼ 32) I: low F ¼ 0.56, fragile I: r w 0.27 g/cm3 (a1 ¼ 0.101 km, a2 ¼ 0.27/s), lower if fragile From c and s: 10,000 y; Earth passing through core of stream (sU < su)

Lightcurve shape: Meteoroid density: Age:

P ( ) 244.6 0.85 þ0.40

Brief history: Compact radiant. Main activity during a narrow time interval on June 4/5. Activity is likely episodic, but number detected starting in 2010: 3, 2, 1, 5, 3, 2, 3, 2, 3, 10, 9, 9. First reported here.

780

North and south poles

July

July 8 (lo ¼ 106 )

686 JRD d June rho Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ1.06  0.58 Annual shower July 2e11 (lo ¼ 100 e110 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 105.5 298.5 þ69.4 281.6 þ78.9 34.7 þ0.62 0.10 1.62 0.20 þ0.05 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 13.8 1.015 0.926 56.0 175.9 105.5 282.5 0.0014 0.111 2.12 2.92 2.10 2.92 þ0.0003 þ0.0089 þ0.45 þ0.42 þ1.00 þ1.42 w0.1/h (N ¼ 67, hr ¼ 55.5 , m(Mv ¼ 0) ¼ 0.11 g) c ¼ 2.39  0.15 (s ¼ 1.94  0.07) Ib: Hb ¼ 102.9  1.47 Mv; Hmax ¼ 94.6 þ 0.16 Mv; He ¼ 88.5 þ 0.89 Mv (N ¼ 40) Ib: low F ¼ 0.55, fragile meteoroids Ib: r  0.42 g/cm3 (a1 ¼ 0.187 km, a2 ¼ 4.17/s), low a2: fragile From c and s: w24,000 y e

781

eV

Brief history: First identified by [1] from R.A. ¼ 297.7 , Decl. ¼ þ66.3 and Vg ¼ 35.2 km/ s around lo ¼ 73.8 . Number and name by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29. July 25 (lo ¼ 123 )

1071 IHD d iota Hydrusids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.99  0.30 Annual shower July 22e30 (lo ¼ 120 e128 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 122.7 44.5 77.0 180.7 73.0 29.8 0.55 0.07 1.12 þ0.14 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.6 0.971 0.980 43.9 24.0 302.7 326.8 eV 0.0043 0.058 1.26 1.24 2.37 1.24 0.0004 þ0.0135 0.15 þ0.01 þ1.00 þ1.01 w0.04/h (N ¼ 20, hr ¼ 38.6 , m(Mv ¼ 0) ¼ 0.15 g) c ¼ 2.63  0.17 (s ¼ 2.05  0.07) Component Ib meteoroids penetrate deep, KE < 82: Ib: Hb ¼ 100.9  0.52 Mv; Hmax ¼ 87.8 þ 2.68 Mv; He ¼ 83.6 þ 2.84 Mv (N ¼ 20) duncertain due to low N Ib: r w 1.0 g/cm3 (a1 ¼ 0.151 km, a2 ¼ 2.91/s) From c and s: w25,000 y e

Meteoroid density: Age: Source:

Brief history: First reported here from video observations. Confirmed by a detection of CAMS New Zealand on July 24 (8:59e18:38 UTC) in 2021 (N ¼ 5), with radiant points included in map. Maybe stronger shower in the past, with [1] reporting a radiant at R.A. ¼ 50 , Decl. ¼ 85 in July. References: [1] Heis E., Neumayer G. (1867) On Meteors in the Southern Hemisphere. Mannheim, 24 pp (p. 15).

782

North and south poles

August

August 26 (lo ¼ 153 )

1177 IVO d iota Volantids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.60  0.40 Annual shower August 18eSeptember 4 (lo ¼ 145 e162 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 152.8 103.6 72.7 87.5 81.2 21.2 þ0.61 þ0.06 2.19 þ0.04 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.16 1.008 0.681 33.1 1.2 332.8 335.0 0.0029 0.078 2.22 6.03 4.75 6.03 0.0002 þ0.0018 0.01 0.41 þ1.00 þ0.59 w0.12/h (N ¼ 121, hr ¼ 34.3 , m(Mv ¼ 0) ¼ 0.33 g) c ¼ 2.26  0.13 (s ¼ 1.88  0.06) Components I and II penetrate deep, KE < 79, like III: I: Hb ¼ 99.8  1.40 Mv; Hmax ¼ 82.9 þ 2.44 Mv; He ¼ 77.1 þ 3.06 Mv (N ¼ 86) IIa: Hb ¼ 94.7  1.43 Mv; Hmax ¼ 86.8 þ 0.09 Mv; He ¼ 81.6 þ 0.78 Mv (N ¼ 15) II: Hb ¼ 89.4  1.07 Mv; Hmax ¼ 78.3 þ 2.11 Mv; He ¼ 72.9 þ 3.04 Mv (N ¼ 19) I: r w 1.3  0.4 g/cm3 (a1 ¼ 0.199 km, a2 ¼ 1.79/s) e e

Meteoroid density: Age: Source:

783

eV

Brief history: First identified here from CAMS low-light video observations in 2019e2021. September 3 (lo ¼ 161 )

201 GDO d gamma Doradids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ0.96  0.29 Annual shower August 27eSeptember 7 (lo ¼ 153 e165 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 160.5 65.1 49.9 239.4 69.1 39.0 þ0.79 þ0.09 þ0.40 0.16 þ0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 12.0 0.975 0.914 64.4 21.3 340.5 2.1 0.0116 0.055 1.55 3.85 2.99 3.85 þ0.0010 þ0.0053 0.01 0.46 þ1.00 þ0.54 w0.2/h; 4.8  1.6 [2] (N ¼ 58, hr ¼ 61.1 , m(Mv¼0) ¼ 0.08 g) c ¼ 3.61  0.17 (s ¼ 2.38  0.06) I: Hb ¼ 106.2  1.45 Mv; Hmax ¼ 94.6 þ 0.66 Mv; He ¼ 88.1 þ 1.54 Mv (N ¼ 55) I: r w 2.1 g/cm3 (a1 ¼ 0.039 km, a2 ¼ 5.07/s) From c and s: w51,000 y e

eV

Brief history: Shower listed by [1], reporting visual observations from R.A. ¼ 61.2 , Decl. ¼ 50.2 around lo ¼ 155.7 . Name by [1]. Number given by [2]. References: [1] Wood J. (2008) List of Meteor Showers by date of Maximum, Perth: NAPOMS, 6 pp.; [2] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 722.

784

North and south poles

785

September

September 7 (lo ¼ 164 ) 851 BEC d beta Carinids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2017-Nov-06.0 TDB

Jupiter-family comet, TJ ¼ þ2.60  0.41 Annual shower August 12eSeptember 28 (lo ¼ 139 e185 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 164.4 115.0 71.1 56.3 78.2 20.7 þ0.08 0.19 0.10 þ0.13 0.02 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.20 1.0044 0.704 31.8 354.0 344.4 337.3 eV 0.0067 0.0824 2.55 6.31 10.08 6.31 0.0003 þ0.0017 0.06 0.07 þ1.00 þ0.93 w0.2/h (N ¼ 303, hr ¼ 33.6 , m(Mv ¼ 0) ¼ 0.35 g) c ¼ 2.72  0.13 (s ¼ 2.09  0.05) Components I (KE < 82) and IIb (Ke < 79) penetrate deep: I: Hb ¼ 98.7  1.42 Mv; Hmax ¼ 84.0 þ 1.83 Mv; He ¼ 77.6 þ 2.80 Mv (N ¼ 251) IIb: Hb ¼ 86.6  0.43 Mv; Hmax ¼ 79.6 þ 1.28 Mv; He ¼ 76.9 þ 2.46 Mv (N ¼ 48) I: r w 1.7  0.2 g/cm3, I: (a1 ¼ 0.142 km, a2 ¼ 2.02/s) IIb: r w 2.1 g/cm3, I: (a1 ¼ 0.223 km, a2 ¼ 3.12/s) dpossibly Na poor/free e 21P/Giacobini-Zinner duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.50 1.013 0.711 32.0 172.8 195.4 368.2

Brief history: First reported by [1] from 21 meteors radiating from R.A. ¼ 139.8 , Decl. ¼ 73.9 and Vg ¼ 17.7 km/s around lo ¼ 170.2 . The center of the stream appears to be just outside of Earth’s orbit. Possible source 21P identified here. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29. September 18 (lo ¼ 175 ) 678 SZP e September zeta Puppids Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Meteoroid density:

Age: Source:

[see plates on p. 84]

Long-period comet, TJ ¼ þ0.63  0.41 Annual shower September 7 e 28 (lo ¼ 164 e 185 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 175.2 114.8 39.9 314.1 59.6 41.6 þ0.59 0.12 0.08 0.05 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 27.7 0.882 0.968 67.8 318.8 355.2 315.2 0.0197 0.118 6.3 3.82 4.63 3.82 0.0006 0.0026 þ0.03 0.10 þ1.00 þ0.90 w0.05 /h (N ¼ 165, hr ¼ 42.2 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 3.13  0.33 (s ¼ 2.24  0.11) I: Hb ¼ 107.7  1.71 Mv; Hmax ¼ 92.8 þ 2.13 Mv; He ¼ 88.2 þ 2.40 Mv (N ¼ 32) IIb: Hb ¼ 98.0  0.98 Mv; Hmax ¼ 88.4 þ 1.48 Mv; He ¼ 83.9 þ 1.42 Mv (N ¼ 79) IIIb: Hb ¼ 91.6  0.11 Mv; Hmax ¼ 86.2 þ 1.09 Mv; He ¼ 82.6 þ 1.07 Mv (N ¼ 51) I: r w 0.92 g/cm3 (a1 ¼ 0.055 km, a2 ¼ 6.47 /s) IIb: r w 2.7 g/cm3 (a1 ¼ 0.097 km, a2 ¼ 5.37 /s) IIIb: r w 2.3 g/cm3 (a1 ¼ 0.056 km, a2 ¼ 8.61 /s) From c and s: w82,000 y -.-

Brief history: First reported here.

eV

786

North and south poles

787

September

September 10 (lo ¼ 168 ) 795 SUR d September Ursae Majorids

Meteoroid density:

Mellish-type shower, toroidal, TJ ¼ þ1.05  0.24 Annual shower September 1e20 (lo ¼ 158 e178 ) lo (  ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 167.7 195.0 þ61.3 345.1 þ58.8 33.4 þ0.79 0.49 þ0.20 0.05 0.07 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.4 0.850 0.946 49.1 133.1 167.4 299.8 eV 0.0140 0.080 1.60 2.42 5.57 2.42 0.0006 0.0045 0.18 0.11 þ1.00 þ0.89 w0.06/h (N ¼ 31, hr ¼ 30.0 , m(Mv ¼ 0) ¼ 0.12 g) c ¼ 3.92  0.59 (s ¼ 2.48  0.17) Component IIa has high He, Ke > 82: IIa: Hb ¼ 100.5  0.21 Mv; Hmax ¼ 92.3 þ 1.99 Mv; He ¼ 87.4 þ 2.62 Mv (N ¼ 18) duncertain due to low N IIa: r w 1.3 g/cm3 (a1 ¼ 0.102 km, a2 ¼ 3.93/s)

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Median: Number observed:

September 10e12 (lo ¼ 168 e171 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 170.3 297.5 þ61.0 345.4 þ0.74 0.48 þ0.16 a (AU) q (AU) e i ( ) 7.1 0.852 0.880 46.9 0.024 0.218 5.2 21.0 0.84 0.961 48.6 N ¼ 12; N ¼ 9096 [1]

Age: Source:

From c: w74,000 y; sU > su: significant radiant drift e

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

b ( ) þ59.1 0.05 u ( ) 134.5 9.2 131.3

Vg (km/s) 34.2 0.11 U ( ) 170.3 1.1 170.5

P ( ) 303.8 9.2 301.8

e R[H] e R[1]

Brief history: Strong shower in 2002e2015 CMOR radar observations, with constant activity from year to year [1] from R.A. ¼ 196.0 , Decl. ¼ 59.8 and Vg ¼ 34 km/s around lo ¼ 171 . Only weak detection in low-light video observations, which show a steep magnitude size distribution index. The shower is not detected by MAARSY. Data from the Harvard Radio Meteor Project and other radars in the MDC data archive show a weak signal at this position that may constitute a confirmation (Fig. 12.2). Name and number by [1]. References: [1] Brown P. G. (2016) Proceedings of the 2016 International Meteor Conference, Egmond, the Netherlands, 2e5 June 2016. Eds: Roggemans A., Roggemans P., Mechelen: IMC, pp. 42e45.

FIG 12.2

Harvard Project and other radars.

788

North and south poles

789

October

October 15 (lo ¼ 202 )

842 CRN d A Carinids

Dynamic type: Shower type: Years of outbursts: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median radiant altitude: Date of peak activity: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.29  0.26 Episodic shower 2014, 2019/2020 October 9e18 (lo ¼ 196 e205 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 201.61 99.0 54.2 272.2 76.9 32.7 (2020) 0.17 þ0.49 2.10 þ0.46 þ0.21 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.44 0.997 0.710 54.9 0.7 21.6 22.2 eV 0.0022 0.177 2.92 2.09 1.21 2.09 0.0005 0.0041 þ0.47 þ0.29 þ1.00 þ1.29 hr ¼ 48.8 (m(Mv ¼ 0) ¼ 0.12 g) 2014: lo ¼ 201.05  0.48 ; 2019: 201.40  0.25 ; 2020: 201.61  0.04 var. (2014: N ¼ 15; 2019: N ¼ 69; 2020: N ¼ 549) c ¼ 2.56  0.09 (s ¼ 2.02  0.04) Component I penetrates deep, KE < 82; IIb has low He, Ke < 79, like III: I: Hb ¼ 103.9  0.71 Mv; Hmax ¼ 92.9 þ 1.53 Mv; He ¼ 84.4 þ 3.03 Mv (N ¼ 289) IIb: Hb ¼ 94.0  0.27 Mv; Hmax ¼ 84.9 þ 1.66 Mv; He ¼ 81.3 þ 1.71 Mv (N ¼ 107) IIIb: Hb ¼ 87.7 þ 0.31 Mv; Hmax ¼ 82.2 þ 1.44 Mv; He ¼ 78.8 þ 1.48 Mv (N ¼ 251) I: low F ¼ 0.56, fragile meteoroids I: r w 0.54 g/cm3 (a1 ¼ 0.176 km, a2 ¼ 3.29/s), lower if fragile dpossibly Na poor IIb: r w 1.7  0.3 g/cm3 (a1 ¼ 0.122 km, a2 ¼ 5.24/s) IIIb: r w 2.3  0.5 g/cm3 (a1 ¼ 0.0545 km, a2 ¼ 9.25/s) dpossibly Na free

Lightcurve shape: Meteoroid density:

Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Flux:

October 9e18 (lo ¼ 197 e210 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) 201.79 99.7 54.4 272.3 þ0.46 þ0.11 0.05 a (AU) q (AU) e i ( ) 2.51 0.997 0.623 53.9 0.0009 0.179 3.45 0.0003 þ0.0014 þ0.25 N ¼ 663 Flux ¼ 0.029 km2 h1 to Mv ¼ þ9 in 2020 [4]

Age: Source: Orbital elements (J2000.0) Epoch 2017-Nov-06.0 TDB

e 2009 SG18 a (AU) 3.04

q (AU) 0.993

e 0.673

i ( ) 57.9

b ( ) 76.8 þ0.21 u ( ) 0.5 3.33 0.03

Vg (km/s) 31.5 þ0.14 U ( ) 22.5 2.28 þ1.00

u ( ) 204.6

U ( ) 177.4

(2020) P ( ) 22.5 3.33 þ0.97

e R[S]

duncertain P ( ) 22.0

Brief history: Absent in most years, but detected in 2014, from which [1] identified a shower at R.A. ¼ 103.2 , Decl. ¼ 57.0 with Vg ¼ 30.1 km/s. However, the 121 meteors also included members of a nearby stream. An outburst was first evident in 2020, reported by [2,3]. Also detected by the SAAMER radar during 7 days, with mean lg  lo ¼ 271.04 , bg ¼ 76.4 and Vg ¼ 33.3 km/s [4]. The name A Carinids has since been associated with the episodic activity. Possible source 2009 SG18 (H ¼ 17.9) identified here. Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29; [2] Jenniskens P. (2020) CBET 4867. Ed.: D. W. E. Green, Cambridge: CBAT, 1 pp; [3] Jenniskens P. (2020) eMeteorNews 5, 369e370; [4] Bruzzone J. S., Weryk R. J., Janches D., Baumann C., Stober G., Hormaechea J. L. (2020) Plan. Sci. J. 2, 56e62.

790

North and south poles

842 ACNdA Carinids

October

791

October 14 (lo ¼ 201 )

1172 OEC d October epsilon Carinids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.32  0.29 Annual shower October 9e18 (lo ¼ 196 e205 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 200.8 113.9 62.2 326.1 78.5 28.7 0.01 þ0.48 3.11 þ0.27 þ0.43 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.51 0.984 0.712 46.1 345.3 20.8 5.8 eV 0.0052 0.057 3.45 2.81 1.70 2.81 0.0003 0.0052 þ0.75 þ0.03 þ1.00 þ1.03 w0.6/h (N ¼ 159, hr ¼ 42.6 , m(Mv ¼ 0) ¼ 0.17 g) c ¼ 2.58  0.27 (s ¼ 2.03  0.11) Component Ib has low He with Ke < 82: Ib: Hb ¼ 101.5  0.42 Mv; Hmax ¼ 90.0 þ 2.14 Mv; He ¼ 82.6 þ 3.36 Mv (N ¼ 69) III: Hb ¼ 89.2  0.31 Mv; Hmax ¼ 81.3 þ 1.60 Mv; He ¼ 77.0 þ 1.87 Mv (N ¼ 75) Ib: r w 0.71 g/cm3 (a1 ¼ 0.127 km, a2 ¼ 2.71/s) III: r w 2.2  0.8 g/cm3 (a1 ¼ 0.079 km, a2 ¼ 7.34/s) dpossibly Na poor/free e e

Meteoroid density: Age: Source:

Brief history: First identified here from CAMS southern hemisphere low-light video observations in 2019e2021. Perhaps a tail of activity belonging to shower #842. October 9 (lo ¼ 205 )

242 XDR d xi Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Median: Peak ZHR: Magn. distribution index: Lightcurve:

Asteroid or Jupiter-family comet, TJ ¼ þ3.80  0.69 Annual shower September 24eNovember 12 (lo ¼ 181 e230 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 204.7 161.1 þ75.8 271.3 þ59.2 38.0 þ1.48 0.30 0.13 0.00 þ0.01 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 1.49 0.993 0.336 72.1 181.1 204.7 21.2 eV 0.0090 0.130 3.44 12.7 14.9 12.7 0.0004 þ0.0005 þ0.00 þ0.29 þ1.00 þ1.29 1.28 0.988 0.228 69.0 175.3 210.8 26.1 e [2] w0.03/h (N ¼ 148, hr ¼ 38.4 , m(Mv ¼ 0) ¼ 0.08 g) c ¼ 3.32  0.48 (s ¼ 2.30  0.15) Ib: Hb ¼ 104.9 þ 0.58 Mv; Hmax ¼ 96.0 þ 2.52 Mv; He ¼ 91.6 þ 2.16 Mv (N ¼ 15) IIb: Hb ¼ 94.1 þ 2.06 Mv; Hmax ¼ 89.8 þ 2.27 Mv; He ¼ 85.0 þ 2.54 Mv (N ¼ 77) IIIb: Hb ¼ 88.9 þ 1.12 Mv; Hmax ¼ 84.9 þ 1.89 Mv; Hend ¼ 77.6 þ 2.37 Mv (N ¼ 17) Ib: F ¼ 0.64; IIb: F ¼ 0.42 Ib: r w 0.68 g/cm3 (a1 ¼ 0.253 km, a2 ¼ 2.65/s) duncertain due to low N dpossibly Na free IIb: r w 2.9 g/cm3 (a1 ¼ 0.017 km, a2 ¼ 10.17/s) e e

Lightcurve shape: Meteoroid density: Age: Source:

[see plate on p. 788]

Brief history: Toroidal shower first detected by radar in the Harvard Meteor Project by [1], with radiants at R.A ¼ 190.1 , Decl. ¼ þ78.9 and Vg ¼ 38.0 km/s around lo ¼ 196.3 and R.A. ¼ 176.6 , Decl. ¼ þ70.9 and Vg ¼ 39.3 km/s around lo ¼ 194.1 . Confirmed by [2] from R.A. ¼ 170.3 , Decl. ¼ þ73.3 with Vg ¼ 35.8 km/s around lo ¼ 210.8 . Here confirmed as a weak shower in video observations. Name by [2], number by [3]. References: [1] Sekanina Z. (1973) Icarus 18, 257e259; [2] Sekanina Z. (1976) Icarus 27, 265e321; [3] Jenniskens P. (2006) Meteor Showers and their Parent Comets. Cambridge: CUP, p. 733.

792

North and south poles

December

793

December 6 (lo ¼ 254 )

303 LVL d lambda Velids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Number observed: Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.28  0.22 Annual shower November 22eDecember 22 (lo ¼ 240 e269 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 253.8 134.4 48.5 269.6 60.9 42.7 þ0.79 0.39 þ0.34 0.03 0.00 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.83 0.982 0.652 75.6 1.5 73.8 75.9 eV 0.0078 0.136 3.79 10.3 6.32 10.3 þ0.0001 þ0.0005 0.02 0.48 þ1.00 þ0.51 N ¼ 4054 (hr ¼ 55.1 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 4.5  0.7/h, B ¼ 0.034  0.006/ [4] 3.20  0.28 (s ¼ 2.26  0.10); 2.9 [4] Component Ib has high He, Ke > 82; II has low He, KE < 79, like III: Ib: Hb ¼ 105.7  1.47 Mv; Hmax ¼ 94.9 þ 0.74 Mv; He ¼ 89.5 þ 1.20 Mv (N ¼ 1050) II: Hb ¼ 99.7  1.15 Mv; Hmax ¼ 90.3 þ 1.33 Mv; He ¼ 85.1 þ 1.81 Mv (N ¼ 2392) III: Hb ¼ 94.7  1.17 Mv; Hmax ¼ 88.3 þ 0.98 Mv; He ¼ 83.7 þ 1.24 Mv (N ¼ 611) Ib: r w 1.3  0.5 g/cm3 (a1 ¼ 0.065 km, a2 ¼ 1.26/s) dpossibly Na poor II: r w 1.5  0.2 g/cm3 (a1 ¼ 0.062 km, a2 ¼ 7.20/s) III: r w 2.3  0.8 g/cm3 (a1 ¼ 0.034 km, a2 ¼ 11.80/s) dpossibly Na free e 746 EVEde Velids [5]; “Puppid-Velids” [6] 96P/Machholzduncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.03 0.124 0.959 58.5 14.7 94.4 109.1

Meteoroid density:

Age: Alternative name: Source: Orbital elements (J2000.0) Epoch 2008-Nov-03.0 TDB

FIG 12.3 ZHR profile.

Brief history: Counterpart to #334. Center of stream just outside Earth orbit. “VelaPuppis” meteor shower detected first with Adelaide radar by [1] from R.A. ¼ 112 e126 , Decl. ¼ 41 to 49 November 17e December 8. NAPO-MS observers long recognized a shower called l-Velids, active November 27 to December 17, peaking on Dec 8 (lo ¼ 256 ), from R.A. ¼ 136 , Decl. ¼ 45 [2], or “Puppids-Velids” from R.A. ¼ 135 , Decl. ¼ 46 [3]. Based on [2], but [4] gives the wrong activity range. The first measured radiant positions from lowlight video data by [5], calling shower “eVelids.” Activity curve in Fig. 12.3. Source based on assumption of relation to #334. Lowest number among candidate showers assigned here based on [4], and name by [2].

References: [1] Ellyett C. D., Roth K. W. (1964) AuJPh 17, 505e514; [2] Wood J. (2008) List of Meteor Showers by date of Maximum, Perth: NAPO-MS, 6 pp.; [3] Jenniskens P. (1994) AA 287, 990e1013; [4] Jenniskens P. (2006) Meteor Showers and their Parent Bodies. Cambridge: CUP, p. 517; [5] Jenniskens P., et al. (2016) Icarus 266, 384e409; [6] Rendtel J. (2021) 2022 Meteor Shower Calendar. Potsdam: IMO, p. 25.

794

North and south poles

December

December 4 (lo ¼ 225 )

336 DKD d December kappa Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Model: (7000 y, br ¼ 0.000) Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ0.89  0.52 Annual shower November 26eDecember 13 (lo ¼ 244 e261 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 251.2 187.1 þ69.9 244.4 þ61.7 43.5 þ1.05 0.50 0.36 þ0.04 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.01 0.930 0.897 72.9 208.2 251.2 99.7 0.0148 0.181 3.99 4.57 2.87 4.57 þ0.0010 þ0.0010 þ0.09 0.35 þ1.00 þ0.65 19.2 0.911 0.952 72.2 209.3 247.2 96.5 w2/h (N ¼ 1982, hr ¼ 40.3 , m(Mv ¼ 0) ¼ 0.06 g) c ¼ 2.71  0.09 (s ¼ 2.08  0.04) I: Hb ¼ 107.7  0.95 Mv; Hmax ¼ 98.5 þ 1.35 Mv; He ¼ 93.3 þ 1.87 Mv (N ¼ 789) IIb: Hb ¼ 95.7  0.13 Mv; Hmax ¼ 91.2 þ 0.58 Mv; He ¼ 86.5 þ 0.91 Mv (N ¼ 87) I: r w 0.54  0.18 g/cm3 (a1 ¼ 0.098 km, a2 ¼ 4.71/s) IIb: r w 1.5  0.9 g/cm3 (a1 ¼ 0.078 km, a2 ¼ 5.04/s) e Na poor/free Mg1.20 Fe0.73 Na0.063 (N ¼ 1); AMOS: Mg1.00 Fe0.38 Na0.029 (N ¼ 2) [6] w7000 y [4]; from c and s: w35,000 y 12P/Pons-Brooks a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 17.0 0.778 0.954 74.7 199.1 256.0 95.1

Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 1966-Oct-07.0 TDB

795

eV e [4]

Brief history: First described by [1] from SonotaCo network video data with R.A. ¼ 186.0 , Decl. ¼ 70.1 and Vg ¼ 43.4 km/s around lo ¼ 250.2 . Confirmed by [2] from single-station and by [3] from double-station video. Association with 96P by [4]. Association with 12P by [5], predicting for “Filament F1” a radiant R.A. ¼ 182.0  5.2 , Decl. ¼ þ73.2  3.4 and Vg ¼ 43.8  1.7 km/s around lo ¼ 247.3  2.3 for 7000 y evolution and br ¼ 0.000. Radiant and elements stay close to the same over 7000e35,000 year period, but increasing dispersion of u and U implies relatively young age. Name and number by [1]. References: [1] Kanamori T. (2009) JIMO 37, 55e62; [2] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Abedin A., et al. (2018) Icarus 300, 360e385; [5] Tomko D., Neslusan L. (2016) AA 592, A107eA119; [6] Matlovic P., et al. (2019) AA 629, A71eA90.

November 30 (lo ¼ 248 )

1173 VAC d November A Carinids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Mellish-type shower, TJ ¼ þ1.10  0.30 Annual shower November 22eDecember 12 (lo ¼ 240 e259 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 247.5 105.5 53.0 238.8 74.2 35.5 þ0.21 0.15 0.33 0.09 0.09 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 9.10 0.969 0.894 57.0 15.7 67.6 83.9 eV 0.0099 0.136 4.45 5.00 5.25 5.00 þ0.0000 0.0001 0.09 0.06 þ1.00 þ0.94 w0.2/h (N ¼ 261, hr ¼ 58.6 , m(Mv ¼ 0) ¼ 0.10 g) c ¼ 2.39  0.05 (s ¼ 1.94  0.02) I: Hb ¼ 104.6  1.03 Mv; Hmax ¼ 92.3 þ 1.92 Mv; He ¼ 87.0 þ 2.40 Mv (N ¼ 201) II: Hb ¼ 96.6  0.74 Mv; Hmax ¼ 86.9 þ 1.42 Mv; He ¼ 82.3 þ 1.78 Mv (N ¼ 37) III: Hb ¼ 90.1  0.46 Mv; Hmax ¼ 81.5 þ 2.19 Mv; He ¼ 78.4 þ 1.92 Mv (N ¼ 15) I: r w 0.51 g/cm3 (a1 ¼ 0.064 km, a2 ¼ 662/s) II: r w 1.6 g/cm3 (a1 ¼ 0.106 km, a2 ¼ 3.84/s) dpossibly Na poor III: r w 3.2 g/cm3 (a1 ¼ 0.0125 km, a2 ¼ 16.87/s) dpossibly Na free From c and s: w35,000 y e

Meteoroid density:

Age: Source:

796

North and south poles

336 DKDdDecember kappa Draconids

November

797

Brief history: First identified here from southern hemisphere CAMS observations in 2019e2021. November 28 (lo ¼ 244 )

392 NID d November i Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.47  0.34 Annual shower November 12eDecember 11 (lo ¼ 230 e259 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 243.6 193.3 þ66.7 258.6 þ61.4 41.8 þ0.98 0.40 þ0.12 þ0.06 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.76 0.973 0.648 73.8 195.4 243.6 79.8 eV 0.0136 0.140 4.30 7.06 7.40 7.06 þ0.0004 0.0019 0.09 0.20 þ1.00 þ0.80 w1/h (N ¼ 1906, hr ¼ 38.0 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 3.00  0.08 (s ¼ 2.19  0.03) Components not well separated. I: Fragile: low F ¼ 0.49, high He: I: Hb ¼ 108.0  1.74 Mv; Hmax ¼ 100.4  0.54 Mv; He ¼ 95.0  0.03 Mv (N ¼ 288) II: Hb ¼ 98.9  0.37 Mv; Hmax ¼ 91.5 þ 1.19 Mv; He ¼ 86.2 þ 1.53 Mv (N ¼ 698) I: r  0.90 g/cm3 (a1 ¼ 0.082 km, a2 ¼ 3.37/s), low a2: fragmentation II: r w 1.6  0.4 g/cm3 (a1 ¼ 0.079 km, a2 ¼ 4.91/s)dpossibly Na poor 96P captured by Jupiter: w20,000 y [6]; Formation Marsden group 1100e1900 y [6]; Mostly 96P 10,000e20,000 y [6] 2009 WN25 duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.33 1.220 0.634 71.2 181.2 231.9 53.1

Meteoroid density: Age: Source: Orbital elements (J2000.0) Epoch 2008-Nov-03.0 TDB

Brief history: First described from CMOR radar observations by [1] with 2059 meteors radiating from R.A. ¼ 200.1 , Decl. ¼ þ64.5 , Vg ¼ 43.0 km/s around lo ¼ 241.0 . Confirmed from video observations by [2], who called the shower #753 NEDdNovember Draconids. [3] specifically assigned the name to meteors in the same complex not associated with showers #334 and #336. Here, we assign the shower to the central part of the complex, which is separated from other showers in radiant space. ZHR profiles for the three high latitude showers in the complex are shown in Fig. 12.4. Association with 2009 WN25 by [4], including model. Same assignment by [5], predicting that ejected meteoroids 3000 BCE to 1500 CE would have radiant near R.A. ¼ 194.2 , Decl. ¼ þ68.6 and Vg ¼ 42.0 km/s around lo ¼ 232.8 (230.3e234.6 ). Assignment to 96P by [6] and to 12P/Pons-Brooks by [7]. Name and number by [1]. References: [1] Brown P., et al. (2010) Icarus 207, 66e81; [2] Segon D., Gural P., Andreic Z., Vida D, Skokic I., Novoselnik F. (2015) JIMO 43, 147e150; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Micheli M., Tholen D. J., Jenniskens P. (2016) Icarus 267, 64e67; [5] Segon D., et al. (2017) AA 598, A15eA28; [6] Abedin A., et al. (2018) Icarus 300, 360e385; [7] Tomko D., Neslusan L. (2016) AA 592, A107eA119.

798

North and south poles

December

799

December 8 (lo ¼ 256 )

334 DAD d December alpha Draconids

Dynamic type: Shower type: Year of outburst: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve:

Jupiter-family comet, TJ ¼ þ2.47  0.36 Annual shower, episodic outbursts 2016: lo ¼ 253.0 (250.8e255.5 ), ZHR w 5/h November 13eDecember 22 (lo ¼ 231 e270 ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) lo ( ) 256.0 210.5 þ58.3 273.8 þ62.2 41.5 þ0.53 0.23 0.23 þ0.05 0.04 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.68 0.982 0.634 73.1 176.1 256.0 72.0 eV 0.0069 0.150 3.95 8.90 9.12 8.90 0.0001 þ0.0004 0.07 þ0.27 þ1.00 þ1.27 w1.3/h (N ¼ 2871, hr ¼ 37.8 , m(Mv ¼ 0) ¼ 0.07 g) c ¼ 2.88  0.07 (s ¼ 2.15  0.03) Component II has low He, KE < 79, like III: Ib: Hb ¼ 105.0 þ 0.04 Mv; Hmax ¼ 98.1 þ 1.60 Mv; He ¼ 92.5 þ 2.07 Mv (N ¼ 448) II: Hb ¼ 98.6  0.31 Mv; Hmax ¼ 90.5 þ 1.52 Mv; He ¼ 85.5 þ 1.85 Mv (N ¼ 1019) Ib: low F ¼ 0.55, fragile meteoroids Ib: r  0.81  0.47 g/cm3 (a1 ¼ 0.103 km, a2 ¼ 3.75/s), fragile: low a2 II: r w 1.7  0.2 g/cm3 (a1 ¼ 0.084 km, a2 ¼ 5.31/s) dNa poor Mg1.74 Fe0.79 Na0.024 (N ¼ 3), Na depleted 10,000e20,000 y [3] 96P/Machholz duncertain a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 3.03 0.124 0.959 58.5 14.7 94.4 109.1

Lightcurve shape: Meteoroid density: Spectroscopy: Age: Source: Orbital elements (J2000.0) Epoch 2008-Nov-03.0 TDB

Brief history: First described by [1] from SonotaCo network video data with R.A. ¼ 207.9 , Decl. ¼ 60.6 , and Vg ¼ 41.6 km/s around lo ¼ 256.5 . Confirmed by [2] from single-station video data and by [3] from double-station video observations. Activity curve shown in Fig. 12.4. [6] noticed enhanced rates in 2016, results posted above were found here. IPRMO forward meteor scatter observations hinted at a peak at lo ¼ 251.2 [7]. Association with 2009 WN25 by [4]. Association with 96P by [8 (“Ursids”),5]. Name and number by [1]. References: [1] Kanamori T. (2009) JIMO 37, 55e62; [2] Molau S., Rendtel J. (2009) JIMO 37, 98e121; [3] Jenniskens P., et al. (2016) Icarus 266, 331e354; [4] Micheli M., Tholen D. J., Jenniskens P. (2016) Icarus 267, 64e67; [5] Abedin A., et al. (2018) Icarus 300, 360e385; [6] Johannink C., Breukers M. (2016) eMeteorNews 1, 141e142; [7] Ogawa H. (2017) eMeteorNews 2, 19e20; [8] Babadzhanov P. B., Obrubov Yu. V. (1992) Celestial Mechanics and Dyn. Astron. 54, 111e127.

FIG 12.4

ZHR profiles.

800

North and south poles

December

801

802

North and south poles

February

February 20 (lo ¼ 331 )

1174 DDO d delta Doradids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Lightcurve shape: Meteoroid density: Age: Source:

Mellish-type shower, TJ ¼ þ1.25  0.40 Annual shower February 12e27 (lo ¼ 323 e338 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 331.2 87.4 64.1 94.8 86.6 28.0 0.54 þ0.03 þ0.25 0.03 0.11 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 15.8 0.988 0.937 41.8 359.5 151.3 151.5 0.0006 0.077 1.85 2.56 4.15 2.56 þ0.0002 þ0.0055 0.06 0.34 þ1.00 þ0.66 w0.03/h (N ¼ 31, hr ¼ 46.0 , m(Mv ¼ 0) ¼ 0.18 g) c ¼ 2.08  0.26 (s ¼ 1.80  0.07) Ib: Hb ¼ 99.6  0.76 Mv; Hmax ¼ 90.9 þ 0.84 Mv; He ¼ 84.9 þ 2.02 Mv (N ¼ 27) Ib: low F ¼ 0.59, but KE ¼ 83 km: borderline fragile meteoroids Ib: r w 0.63 g/cm3 (a1 ¼ 0.079 km, a2 ¼ 5.51/s), lower if fragile From c: w9500 y, dU > du: young shower with significant radiant drift e

803

eV

Brief history: Shower very close to ecliptic south pole. First identified here.

February 28 (lo ¼ 339 )

906 ETD d eta Draconids

Dynamic type: Shower type: Period of activity: Shower radiant/speed Median (geocentric): Drift per day (d/dlo): Orbital elements (J2000.0) Median: Dispersion (±s): Drift (d/dlo): Peak ZHR: Magn. distribution index: Lightcurve: Meteoroid density: Age: Source:

Jupiter-family comet, TJ ¼ þ2.67  0.18 Annual shower February 25eMarch 6 (lo ¼ 336 e346 ) lo ( ) R.A. ( ) Decl. ( ) l ( ) b ( ) Vg (km/s) 339.4 246.7 þ57.4 230.0 þ76.0 29.8 þ0.64 0.24 þ0.75 þ0.04 þ0.03 a (AU) q (AU) e i ( ) u ( ) U ( ) P ( ) 2.71 0.975 0.643 49.7 196.4 339.4 177.0 0.0044 0.058 1.77 2.20 2.53 2.20 þ0.0008 0.0019 þ0.10 0.26 þ1.00 þ0.74 w0.05/h (N ¼ 51, hr ¼ 54.8 , m(Mv ¼ 0) ¼ 0.15 g) c ¼ 2.71  0.08 (s ¼ 2.08  0.04) II: Hb ¼ 94.9  0.06 Mv; Hmax ¼ 86.8 þ 0.99 Mv; He ¼ 81.8 þ 1.56 Mv (N ¼ 27) II: r w 2.4 g/cm3 (a1 ¼ 0.069 km, a2 ¼ 4.64/s) e e

eV

Brief history: First identified by [1] from low-light video observations from R.A. ¼ 245.6 , Decl. ¼ þ59.6 and Vg ¼ 28.9 km/s around lo ¼ 339.5 . Name and number by [1]. References: [1] Jenniskens P., et al. (2018) PSS 154, 21e29.

804

North and south poles

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Greek alphabet a

alpha

i

iota

r

rho

b

beta

k

kappa

s

sigma

g

gamma

l

lambda

s

tau

d

delta

m

mu

y

upsilon

ε

epsilon

n

nu

f

phi

z

zeta

x

xi

c

chi

h

eta

o

omicron

j

psi

q

theta

p

pi

u

omega

Note: e.g., alpha-Capricornids ¼ a-Capricornids.

806

Index In order of IAU Number IAU #

Name

1

Page

IAU #

Name

alpha-Capricornids......................................69

47

mu-Virginids ................................................545

2

Southern Taurids.........................................599

55

alpha-Scorpiids ............................................553

3

Southern iota-Aquariids.............................575

61

tau-Herculids ...............................................717

4

Geminids ......................................................101

63

Corvids..........................................................725

5

Southern delta-Aquariids...........................71

65

gamma-Delphinids......................................263

6

April Lyrids..................................................53

69

Southern mu-Sagittariids ...........................169

7

Perseids .........................................................75

81

September Lyncids......................................323

8

Orionids ........................................................87

88

omicron-Draconids......................................779

9

October Draconids ......................................735

96

Northern delta-Cancrids ............................655

10

Quadrantids .................................................107

97

Southern delta-Cancrids.............................657

11

eta-Virginids.................................................125

100

Daytime xi-Saggittariids.............................709

12

kappa-Cygnids.............................................197

101

pi-Hydrids ....................................................515

13

Leonids..........................................................93

102

alpha-Centaurids .........................................531

15

Ursids ............................................................105

107

delta-Chamaleontids ...................................535

16

sigma-hydrids ..............................................99

108

beta-Tucanids...............................................767

17

Northern Taurids ........................................601

110

alpha-Antliids ..............................................667

18

Andromedids ...............................................741

114

Daytime chi-Capricornids..........................711

19

December Monocerotids ............................641

115

Daytime Capricornids-Sagitt. ....................713

20

Comae Berenicids........................................379

120

delta-Pavonids .............................................413

21

alpha-Virginids ............................................721

128

Daytime kappa-Aquariids .........................673

22

Leonis Minorids...........................................345

130

delta-Mensids...............................................47

23

epsilon-Geminids.........................................339

136

sigma-Leonids..............................................51

25

Northern Oct. delta-Arietids .....................619

137

pi-Puppids ....................................................749

26

Northern delta-Aquariids ..........................581

143

Daytime lambda-Pegasids .........................679

27

kappa-Serpentids.........................................237

144

Daytime April Piscids ................................675

28

Southern Oct. delta-Arietids......................607

145

eta-Lyrids......................................................57

31

eta-Aquariids................................................55

148

May gamma-Virginids ...............................549

33

Northern iota-Aquariids ............................585

149

Northern May Opiuchids ..........................555

40

zeta-Cygnids ................................................241

150

Southern May Ophiuchids ........................555

807

Page

808

Index

IAU #

Name

151

Page

IAU #

Name

Page

epsilon-Aquilids ..........................................59

221

Daytime Sexantids ......................................85

152

N. Daytime omega-Cetids .........................143

233

October Capricornids .................................731

153

S. Daytime omega-Cetids ..........................145

242

xi-Draconids .................................................791

155

N. Daytime May Arietids ..........................677

245

November Hydrids.....................................489

156

S. Daytime May Arietids ...........................677

246

alpha-Monocerotids ....................................493

164

Northern June Aquilids..............................65

250

November Orionids ....................................639

165

Southern June Aquilids ..............................67

252

alpha-Lyncids...............................................377

170

June Bootids .................................................723

253

December Canis Minorids .........................647

171

Daytime Arietids .........................................61

254

Phoenicids ....................................................759

172

Daytime zeta-Perseids ................................165

256

Northern chi-Orionids ................................637

173

Daytime beta-Taurids.................................167

257

Southern chi-Orionids ................................635

175

July Pegasids................................................281

281

October Camelopardalids ..........................329

176

July Phoenicids ............................................189

286

omega-Taurids .............................................617

177

beta-Cassiopeids..........................................285

303

lambda-Velids..............................................793

179

sigma-Capriconids ......................................567

304

c-Velids .........................................................513

182

omicron-Cygnids.........................................191

314

alpha-Crucids...............................................523

183

Piscis Austrinids..........................................569

318

mu-Velids .....................................................501

184

July gamma-Draconids...............................193

319

January Leonids...........................................653

187

psi-Cassiopeiids ...........................................277

320

omega-Serpentids ........................................707

188

Daytime xi-Orionids ...................................687

321

theta Coronae Borealids.............................389

191

eta-Eridanids ................................................445

322

lambda-Bootids............................................389

197

August Draconids .......................................79

323

xi-Coronae Borealids...................................395

198

beta-Hydrusids ............................................755

324

epsilon-Perseids ...........................................683

199

August delta-Capriconids..........................579

325

Daytime lambda-Taurids ...........................681

201

gamma-Doradids.........................................783

326

epsilon-Pegasids ..........................................185

202

Daytime zeta-Cancrids ...............................691

327

beta-Equuleids .............................................183

205

xi-Aurigids....................................................313

328

alpha-Lacertids ............................................273

206

Aurigids ........................................................81

330

sigma-Serpentids .........................................383

208

September epsilon-Perseids .......................315

331

alpha-Hydrids..............................................331

212

Daytime kappa-Leonids.............................693

333

October Ursae Majorids .............................337

215

Northern delta-Piscids................................587

334

December alpha-Draconids .......................799

216

Southern delta-Piscids ................................591

335

December chi-Virginids..............................499

219

September mu-Arietids ..............................595

336

December kappa-Draconids ......................795

809

Index

IAU #

Name

337

Page

IAU #

Name

Page

nu-Eridanids.................................................449

416

September iota-Cassiopeiids......................321

338

omicron-Eridanids.......................................207

421

May Microscopiids......................................429

339

psi-Ursae Majorids ......................................367

423

Southern Librids-Lupids ............................551

340

theta-Pyxidids ..............................................499

424

September-October Lyncids ......................315

341

January xi-Ursae Majorids .........................661

426

Daytime Craterids.......................................689

343

h-Virginids....................................................151

427

February eta-Draconids..............................115

345

f-Herculids....................................................231

428

December sigma-Virginids ........................385

346

x-Herculids ...................................................769

429

alpha-Coronae Borealids............................401

347

beta-Pegasids................................................141

431

June iota-Pegasids .......................................265

348

April rho-Cygnids.......................................249

435

mu-Perseids..................................................291

350

May Lacertids ..............................................243

444

zeta-Cassiopeiids .........................................271

351

Daytime Triangulids...................................157

445

kappa-Ursae Majorids ................................355

361

theta-Serpentids ...........................................175

446

December phi-Cassiopeiids .......................743

362

June mu-Cassiopeiids .................................261

450

April epsilon-Delphinids............................235

366

July beta-Pegasids .......................................179

451

Camelopardalids .........................................159

369

July Taurids..................................................685

456

May psi-Scorpiids........................................259

370

Microscopiids...............................................561

458

June epsilon-Cygnids..................................63

372

phi-Piscids ....................................................283

459

June epsilon-Ophiuchids............................559

376

August Lyncids ...........................................309

465

August xi-Cassiopeiids...............................293

381

Daytime pi-Leonids ....................................697

480

tau-Cancrids .................................................341

384

October Leporids.........................................475

486

November zeta-Perseids ............................645

386

Oct. beta-Camelopardalids ........................733

488

Nov. sigma-Ursae Majorids.......................363

388

chi-Taurids....................................................91

494

December Lyncids.......................................369

390

November theta-Aurigids..........................645

497

December alpha-Bootids ............................375

392

November i-Draconids ...............................797

502

December rho-Virginids.............................365

393

rho-Bootids ...................................................373

505

August iota-Cetids ......................................583

394

alpha-Canis Majorids..................................495

506

February epsilon-Virginids ........................381

402

January Hydrids..........................................517

510

June rho-Cygnids ........................................63

404

gamma-Ursae Minorids .............................113

512

rho-Puppids..................................................491

405

mu-Hydrids..................................................527

514

omega-Capricornids....................................423

409

nu-Cygnids...................................................241

515

omicron-Leonids..........................................663

410

delta-Piscids .................................................171

516

February mu-Virginids...............................407

411

c-Andromedids ............................................265

517

April lambda-Ophiuchids..........................49

810

Index

IAU #

Name

518

Page

IAU #

Name

April 102-Herculids ....................................245

587

59-Cygnids ...................................................729

519

beta-Aquariids .............................................149

590

10-Canum Venaticids .................................393

520

May beta-Capricornids...............................253

591

zeta-Bootids..................................................407

523

August gamma-Cepheids ..........................307

593

28-Lyncids ....................................................357

524

lambda-Ursae Majorids..............................353

594

Serpentids-Coronae Borealids ...................397

526

Southern lambda-Draconids......................351

595

13-Taurids.....................................................463

529

eta-Hydrids ..................................................503

602

kappa-Craterids ...........................................519

530

eta-Corvids ...................................................525

610

68-Geminids .................................................211

531

gamma-Aquilids..........................................251

623

xi2-Capricornids...........................................71

533

July xi-Arietids.............................................437

624

xi-Arietids .....................................................609

535

theta-Cetids ..................................................439

625

lambda-Taurids ...........................................615

536

47-Ophiuchids..............................................405

626

lambda-Cetids..............................................611

543

22-Bootids .....................................................391

627

nu-Piscids .....................................................605

545

xi-Cassiopeiids .............................................303

628

s-Taurids .......................................................603

546

43-Cassiopeiids ............................................297

629

A2-Taurids....................................................629

549

49-Andromedids..........................................275

630

tau-Arietids ..................................................623

6

Page

552

pi -Orionids..................................................453

631

delta-Arietids ...............................................621

555

Oct. gamma-Camelopardalids ..................325

632

November eta-Taurids ...............................625

556

phi-Taurids...................................................323

633

p-Taurids ......................................................631

557

64-Draconids ................................................739

634

tau-Taurids ...................................................633

558

27-Monocerotids ..........................................489

635

A1-Taurids....................................................629

567

xi-Hydrids ....................................................509

637

f-Taurids .......................................................613

568

14-Canum Venaticids .................................399

640

August omicron-Aquariids........................577

569

omicron-Hydrids .........................................117

641

December rho-Geminids ............................643

570

February beta-Herculids ............................401

643

omega-Leonids.............................................659

571

26-Bootids .....................................................123

644

January lambda-Leonids ............................649

574

gamma-Ursae Majorids ..............................371

645

phi-Cancrids.................................................327

575

63-Aurigids...................................................361

647

beta-Comae Berenicids ...............................129

578

theta-Ursae Majorids ..................................369

651

68-Virginids..................................................543

580

chi-Andromedids.........................................309

653

R-Lyrids ........................................................775

581

90-Herculids .................................................775

655

April phi-Capricornids ...............................417

582

January beta-Craterids................................519

657

gamma-Sagittariids .....................................415

584

12-Taurids.....................................................447

658

epsilon-Draconids........................................153

811

Index

IAU #

Name

661

Page

IAU #

Name

Page

110-Herculids ...............................................255

727

iota-Serpentids .............................................385

668

June mu-Pegasids........................................257

732

February gamma-Virginids .......................669

669

chi-Pegasids..................................................257

736

xi-Perseids.....................................................291

674

October 44-Hydrids ....................................467

738

rho-Eridanids ...............................................439

676

Oct. epsilon-Monocerotids.........................481

745

October 6-Draconids...................................335

678

September zeta-Puppids ............................785

749

N. March gamma-Virginids ......................665

680

June epsilon-Arietids ..................................163

750

S. March gamma-Virginids........................665

681

omicron-Aquariids ......................................171

752

April alpha-Capricornids ...........................139

682

r-Puppids ......................................................509

756

rho-Phoenicids .............................................149

683

June theta-Serpentids..................................557

757

chi-Cygnids ..................................................83

685

June beta-Pegasids ......................................267

758

Volantids.......................................................111

686

June rho-Draconids .....................................781

760

Octantids.......................................................147

687

kappa-Delphinids........................................565

762

omicron-Pavonids .......................................155

690

March epsilon-Pegasids..............................163

763

upsilon-Pavonids.........................................155

692

epsilon-Aquariids ........................................573

764

Telescopiids ..................................................173

693

August nu-Perseids.....................................305

765

alpha-Sagittariids.........................................179

694

omicron-Geminids.......................................301

768

zeta-Phoenicids ............................................189

695

August psi-Aurigids ...................................305

770

lamda-Caelids ..............................................465

696

omicron-Aurigids ........................................295

771

sigma-Columbids ........................................475

697

April beta-Aquariids...................................129

773

3-Puppids......................................................481

699

omega-Herculids .........................................237

777

October Puppids..........................................483

700

eta-Arids .......................................................507

779

October lambda-Velorids...........................209

701

beta-Cepheids ..............................................307

780

November Puppids.....................................209

705

UY-Lyncids...................................................319

781

November lamba-Velids ............................211

706

zeta-Piscids ...................................................595

783

iota-Lupids ...................................................705

707

beta-Pyxidids ...............................................761

784

kappa-Velids ................................................511

708

R-Leonis Minorids.......................................653

785

theta-Carinids ..............................................217

712

February delta-Cygnids .............................231

789

January mu-Velorids...................................221

713

chi-Cancrids .................................................321

790

psi-Velids ......................................................221

714

rho-Piscids ....................................................593

792

March beta-Equuleids.................................131

715

alpha-Camelopardalids ..............................325

794

gamma-Lyrids..............................................403

720

November gamma-Bootids........................363

795

September Ursae Majorids ........................787

722

15-Leonids ....................................................367

797

epsilon-Gruids .............................................431

812

Index

IAU #

Name

August Caelids ............................................195

851

beta-Carinids................................................785

802

June Aquariids.............................................187

852

alpha-Sculptorids.........................................425

803

lambda-Sagittariids .....................................557

853

zeta-Pavonids...............................................135

810

October Cetids .............................................593

854

psi-Cygnids ..................................................255

812

November alpha-Aurigids.........................371

856

epsilon-Monocerotids .................................461

815

August Ursae Majorids ..............................303

859

March 12-Bootids ........................................229

818

October Aurigids.........................................343

860

psi-Andromedids.........................................263

822

nu-Taurids ....................................................195

861

June xi1-Sagittariids.....................................563

823

56-Cetids .......................................................459

865

June epsilon-Serpentids..............................727

824

December Sextantids ..................................505

867

52-Pegasids...................................................267

825

xi-Eridanids ..................................................469

868

psi3-Aquariids ..............................................187

826

iota1-Librids..................................................547

869

upsilon1-Cassiopeiids..................................285

827

nu-Pegasids ..................................................245

870

July eta-Pegasids .........................................287

828

31-Pegasids...................................................135

872

epsilon-Triangulids .....................................295

829

July 77-Pegasids...........................................275

873

omicron-Cetids ............................................447

830

63-Cygnids ...................................................269

874

September xi-Perseids.................................313

831

gamma-Pegasids..........................................299

875

tau9-Eridanids ..............................................467

833

kappa-Orionids............................................485

876

rho-Orionids.................................................463

834

April theta-Centaurids ...............................543

877

omega-Hydrids............................................479

835

June delta-Pavonids ....................................751

878

October epsilon-Aurigids...........................343

836

April beta-Herculids ...................................239

880

Y-Draconids..................................................327

837

Caelids ..........................................................479

881

theta-Leonids................................................353

838

October delta-Sextantids ............................485

882

phi-Leonids ..................................................487

839

phi-Serpentids..............................................49

885

December epsilon-Virginids ......................387

IAU #

Name

798

Page

4

Page

840

tau -Eridanids ..............................................461

886

alpha-Corvids ..............................................521

841

delta-Herculids ............................................239

887

December zeta-Bootids...............................387

842

A-Carinids ....................................................789

888

6-Corvids ......................................................517

845

October eta-Virginids .................................701

889

Y-Ophiuchids ...............................................403

846

tau-Sculptorids.............................................431

892

March Centaurids .......................................411

847

beta-Leonids.................................................333

893

eta-Ophiuchids.............................................233

848

omicron-Perseids .........................................331

895

Oct. alpha-Comae Berenicids ....................699

849

September zeta-Eridanids ..........................457

897

Oct. alpha-Ursae Minorids ........................349

850

May beta-Aquariids ....................................261

899

epsilon-Microscopiids .................................425

813

Index

IAU #

Name

beta-Bootids..................................................393

1065

nu-Arietids ...................................................269

904

omicron-Columbids ....................................471

1066

Fornacids ......................................................435

906

eta-Draconids ...............................................803

1067

eta-Sculptorids .............................................435

IAU #

Name

900

Page

2

Page

908

xi -Librids .....................................................213

1068

July theta-Perseids.......................................279

909

Sept. epsilon-Columbids ............................473

1069

July omicron-Pavonids ...............................753

915

delta-Normids..............................................537

1070

77-Cetids .......................................................441

917

omicron-Virginids .......................................699

1071

iota-Hydrusids .............................................781

918

theta-Aurigids ..............................................301

1072

August Aquariids........................................571

919

iota-Centaurids ............................................525

1073

gamma-Gruids.............................................571

922

August phi-Pegasids...................................293

1074

July alpha-Camelopardalids......................287

923

15-Bootids .....................................................717

1075

August gamma-Pegasids ...........................289

924

62-Andromedids..........................................203

1077

pi-Casseiopeids ............................................299

925

eta-Andromedids.........................................589

1078

sigma-Fornacids...........................................441

926

October mu-Hydrids ..................................697

1079

August nu-Taurids......................................443

1032

February Hydrids........................................763

1080

August nu-Eridanids ..................................443

1033

omega-Carinids ...........................................523

1085

Northern chi-Aquariids..............................583

1034

gamma-Piscis Austrinids ...........................421

1087

omicron1-Eridanids .....................................455

1035

sigma-Phoenicids.........................................421

1088

17-Eridanids .................................................455

1036

chi-Phoenicids ..............................................429

1089

September tau-Cetids .................................755

1045

September upsilon-Taurids........................201

1090

eta-Orionids..................................................469

1046

29-Piscids ......................................................477

1092

43-Leonis Minorids .....................................359

1047

gamma-Crucids ...........................................119

1093

Nov. Comae Berenicids..............................361

1051

April kappa-Cygnids ..................................773

1094

epsilon-Canis Majorids...............................491

1052

chi-Aquilids ..................................................233

1095

epsilon-Sextantids........................................497

1054

13-Delphinids...............................................235

1096

November alpha-Corvids ..........................497

1055

35-Vulpeculids .............................................139

1097

December omega-Hydrids.........................649

1056

April zeta-Cygnids......................................141

1099

January eta-Draconids ................................391

1057

sigma-Pegasids ............................................247

1100

xi2-Lupids .....................................................529

1058

2-Pegasids.....................................................247

1101

February alpha-Corvids .............................535

1059

May kappa-Aquariids ................................423

1103

January 15-Bootids......................................397

1061

epsilon-Ophiuchids .....................................549

1104

Apodids ........................................................529

1

1063

eta -Coronae Australids .............................551

1105

upsilon-Virginids.........................................229

1064

June eta-Eridanids.......................................433

1106

gamma-Draconids .......................................773

814

Index

IAU #

Name

Page

1121

December alpha-Lyncids............................651 2

IAU #

Name

Page

1167

14-Orionids...................................................597

1129

June theta -Sagittariids ...............................181

1168

delta1-Canis Minorids.................................663

1130

Arids..............................................................757

1170

10-Leonis Minorids .....................................651

1131

October zeta-Perseids .................................347

1171

Jan. gamma-Camelopardalids ...................745

1133

32-Cassiopeiids ............................................279

1172

October epsilon-Carinids ...........................791

1134

pi-Perseids ....................................................311

1173

November A-Carinids ................................795

1135

July omega-Piscids ......................................289

1174

delta-Doradids .............................................803

1136

Aug. gamma-Camelopardalids.................297

1175

February Herculids .....................................405

1137

August mu-Perseids ...................................311

1176

77-Herculids .................................................769

1

1138

chi -Hydrids.................................................527

1177

iota-Volantids...............................................783

1139

June epsilon Gruids ....................................427

1178

rho-Draconids ..............................................779

1140

eta-Microscopiids ........................................427

1180

December alpha-Antliids ...........................505

2

1141

iota - Fornacids............................................433

1181

September 72-Ophiuchids..........................731

1144

July kappa-Velids........................................753

1182

xi1-Centaurids ..............................................541

1146

delta-Horologiids.........................................199

1183

January mu-Hydrids...................................219

1147

Northern Librids .........................................215

1184

rho-Centaurids.............................................219

1148

Southern Librids..........................................215

1185

87-Virginids..................................................541

1149

October xi-Perseids .....................................331

1186

psi1-Piscids ...................................................147

1150

October gamma-Cepheids .........................333

1187

35-Eridanids .................................................473

1152

November sigma-Bootids ..........................357

1188

31-Ursae Majorids .......................................351

1153

23 Ophiuchids..............................................383

1189

20-Aquariids.................................................183

1154

December psi-Ursae Majorids ...................375

1190

January zeta-Leonids ..................................223

1155

Feb. beta-Comae Berenicids ......................399

1191

80-Virginids..................................................223

1156

September gamma-Eridanids ....................457

1192

zeta-Virginids...............................................359

1158

25-Sextantids ................................................487

1207

omicron-Piscids............................................675

1159

chi-Virginids.................................................507

1208

62-Sagittariids ..............................................713

1162

December psi-Velids ...................................501

1209

58-Ophiuchids..............................................709

1163

Pixidids .........................................................513

1210

gamma-Geminids ........................................685

1164

Normids........................................................533

1211

74-Geminids .................................................687

1166

theta-Trianguli Australids..........................537

815

Index

In order of IAU Code Code

Page

Code

Page

Code

Page

AAC............................................. 139

APO............................................. 529

CAQ ............................................ 233

AAN ............................................ 667

APS .............................................. 675

CCR ............................................. 321

ABH............................................. 239

ARC............................................. 249

CCY ............................................. 83

ACA............................................. 495

ARD............................................. 757

CHA ............................................ 309

ACB ............................................. 401

ARI .............................................. 171

CHP ............................................. 257

ACD............................................. 195

ASC.............................................. 553

CMI.............................................. 647

ACE ............................................. 531

ASG ............................................. 179

COH ............................................ 527

ACL ............................................. 325

AST.............................................. 425

COM............................................ 379

ACR............................................. 523

ATS.............................................. 629

COR............................................. 725

ACU............................................. 543

ATU............................................. 629

CPH ............................................. 429

ACV............................................. 521

AUA ............................................ 571

CRN............................................. 789

ADC............................................. 579

AUD ............................................ 79

CTA ............................................. 91

ADS ............................................. 187

AUR............................................. 81

CTS .............................................. 755

AED............................................. 235

AVB ............................................. 721

CVE ............................................. 513

AGA ............................................ 297

AXC............................................. 293

CVI .............................................. 507

AGC............................................. 307

AZC............................................. 141

DAB............................................. 375

AGP ............................................. 289

BAQ............................................. 149

DAD ............................................ 799

AHE............................................. 245

BBO.............................................. 393

DAN ............................................ 505

AHY ............................................ 331

BCA ............................................. 285

DAT............................................. 621

AIC .............................................. 583

BCE.............................................. 307

DCH ............................................ 535

AKC............................................. 773

BCO ............................................. 129

DCN ............................................ 663

ALA............................................. 273

BEA.............................................. 129

DCR............................................. 689

ALN............................................. 309

BEC.............................................. 785

DCS.............................................. 713

ALO............................................. 49

BEL .............................................. 333

DDO ............................................ 803

ALY ............................................. 377

BEQ.............................................. 183

DEL.............................................. 369

AMO............................................ 493

BHY ............................................. 755

DEV ............................................. 387

AMP ............................................ 311

BPG.............................................. 141

DEX ............................................. 505

AND ............................................ 741

BPX .............................................. 761

DHE............................................. 239

ANE............................................. 443

BTA.............................................. 167

DHO ............................................ 199

ANP............................................. 305

BTU.............................................. 767

DKD ............................................ 795

ANT............................................. 443

CAE ............................................. 479

DLI............................................... 545

AOA ............................................ 577

CAM............................................ 159

DLT.............................................. 681

APA ............................................. 305

CAN ............................................ 265

DME ............................................ 47

APC ............................................. 417

CAP ............................................. 69

DNO ............................................ 537

816 Code

Index

Page

Code

Page

Code

Page

DOH ............................................ 649

ERI ............................................... 445

GAC............................................. 333

DPA ............................................. 413

ESC .............................................. 435

GAD ............................................ 773

DPC ............................................. 743

ESV .............................................. 541

GAE ............................................. 457

DPI............................................... 171

ETA.............................................. 55

GAG ............................................ 685

DPL.............................................. 697

ETD.............................................. 803

GAQ ............................................ 251

DPU ............................................. 375

ETM............................................. 427

GCR ............................................. 119

DPV ............................................. 501

ETR .............................................. 295

GDE ............................................. 263

DRA............................................. 735

EVI............................................... 125

GDO ............................................ 783

DRG............................................. 643

FAC ............................................. 535

GDR............................................. 193

DRV............................................. 365

FAN............................................. 275

GEM ............................................ 101

DSV ............................................. 385

FBC .............................................. 399

GGR............................................. 571

DSX.............................................. 85

FBH.............................................. 401

GLY ............................................. 403

DTR ............................................. 157

FBI................................................ 397

GMA............................................ 371

DXC............................................. 711

FBO.............................................. 717

GPA ............................................. 421

DZB ............................................. 387

FCE .............................................. 459

GPG ............................................. 299

EAN............................................. 589

FCV.............................................. 399

GSG ............................................. 415

EAR ............................................. 507

FDC ............................................. 231

GUM............................................ 113

EAU............................................. 59

FED.............................................. 115

HVI .............................................. 151

ECV ............................................. 525

FEV .............................................. 381

HYD ............................................ 99

EDR ............................................. 153

FGV ............................................. 669

ICN .............................................. 525

EGE.............................................. 339

FHD............................................. 467

IHD.............................................. 781

EGR ............................................. 431

FHE.............................................. 231

ILI ................................................ 547

EHY ............................................. 503

FHL.............................................. 405

ILU............................................... 705

EIV............................................... 223

FHY ............................................. 763

ISR ............................................... 385

ELY .............................................. 57

FLE .............................................. 367

IVO .............................................. 783

EMA ............................................ 491

FLM ............................................. 359

JAC .............................................. 287

EMC............................................. 425

FMV............................................. 407

JBC ............................................... 519

EMO ............................................ 461

FNC ............................................. 729

JBO............................................... 723

EOC ............................................. 551

FOD ............................................. 597

JBP ............................................... 179

EOP.............................................. 233

FOR.............................................. 435

JDP............................................... 751

EOR ............................................. 469

FOS .............................................. 709

JEA............................................... 163

EPG.............................................. 185

FPE............................................... 267

JEC ............................................... 63

EPO.............................................. 549

FSO .............................................. 405

JED............................................... 391

EPR .............................................. 683

FTA.............................................. 617

JEO............................................... 559

EPX .............................................. 497

FTC .............................................. 297

JEG............................................... 427

EQA............................................. 573

FTR .............................................. 613

JER ............................................... 433

817

Index

Code

Page

Code

Page

Code

Page

JES................................................ 727

LCT.............................................. 611

NGB............................................. 363

JGC .............................................. 745

LEO.............................................. 93

NHD............................................ 489

JHY .............................................. 517

LMI .............................................. 345

NHE............................................. 775

JIP................................................. 265

LPE .............................................. 679

NIA.............................................. 585

JKV .............................................. 753

LSA.............................................. 557

NID.............................................. 797

JLE ............................................... 653

LTA.............................................. 615

NLI .............................................. 215

JLL ............................................... 649

LTM............................................. 651

NLV............................................. 211

JMC.............................................. 261

LUM ............................................ 353

NMA ........................................... 677

JMH ............................................. 219

LVL.............................................. 793

NMV............................................ 665

JMP .............................................. 257

LYR.............................................. 53

NOA ............................................ 619

JMV.............................................. 221

MAL ............................................ 243

NOC ............................................ 143

JOM ............................................. 289

MBA ............................................ 261

NOO ............................................ 639

JOP............................................... 753

MBC............................................. 253

NOP............................................. 555

JPE ............................................... 281

MBE............................................. 131

NOR ............................................ 533

JPG............................................... 287

MCN............................................ 411

NPE ............................................. 245

JPS................................................ 267

MEP ............................................. 163

NPI............................................... 587

JRC............................................... 63

MHY............................................ 527

NPS.............................................. 605

JRD .............................................. 781

MIC.............................................. 561

NPU............................................. 209

JSP................................................ 275

MKA............................................ 673

NSB.............................................. 357

JTR ............................................... 685

MKQ............................................ 423

NSU ............................................. 363

JTS................................................ 557

MLV ............................................ 549

NTA............................................. 601

JTT ............................................... 181

MMI............................................. 429

NUE............................................. 449

JXA .............................................. 437

MON ........................................... 641

NUT............................................. 195

JXS ............................................... 563

MPR............................................. 291

NZC............................................. 65

KCG............................................. 197

MPS ............................................. 259

NZP ............................................. 645

KCR ............................................. 519

MTB............................................. 229

OAB............................................. 699

KDP ............................................. 565

MVE ............................................ 501

OAG ............................................ 343

KLE.............................................. 693

NAA ............................................ 371

OAQ ............................................ 171

KOR............................................. 485

NAC ............................................ 497

OAU ............................................ 295

KPG ............................................. 139

NAT............................................. 269

OAV ............................................ 543

KSE .............................................. 237

NCB ............................................. 361

OBC ............................................. 733

KUM............................................ 355

NCC............................................. 655

OCC............................................. 731

KVE ............................................. 511

NCQ ............................................ 583

OCD ............................................ 147

LAD............................................. 651

NCY............................................. 241

OCE ............................................. 145

LBO.............................................. 389

NDA ............................................ 581

OCO ............................................ 471

LCA ............................................. 465

NET ............................................. 625

OCP ............................................. 325

818 Code

Index

Page

Code

Page

Code

Page

OCR............................................. 523

OVI .............................................. 699

RLY.............................................. 775

OCT ............................................. 329

OXP ............................................. 331

ROR ............................................. 463

OCU ............................................ 337

OZP ............................................. 347

RPH ............................................. 149

OCY............................................. 191

PAN............................................. 263

RPI ............................................... 593

ODR............................................. 779

PAU ............................................. 569

RPP .............................................. 509

ODS ............................................. 485

PCA ............................................. 277

RPU ............................................. 491

OEA............................................. 343

PCY.............................................. 255

RSE .............................................. 397

OEC ............................................. 791

PER .............................................. 75

SAN ............................................. 203

OEM ............................................ 481

PHC ............................................. 327

SAR.............................................. 595

OER ............................................. 207

PHE ............................................. 189

SAU ............................................. 361

OES.............................................. 713

PHI............................................... 279

SCA.............................................. 567

OEV ............................................. 701

PHO............................................. 759

SCC.............................................. 657

OFO ............................................. 433

PIC ............................................... 299

SCE .............................................. 441

OHD ............................................ 479

PIE ............................................... 311

SCO ............................................. 475

OHE............................................. 237

PIH............................................... 515

SCV.............................................. 517

OHY ............................................ 117

PIS................................................ 477

SCY.............................................. 269

OLE.............................................. 663

PLE .............................................. 487

SDA ............................................. 71

OLP.............................................. 475

PPE .............................................. 293

SEC .............................................. 473

OLS.............................................. 659

PPS............................................... 283

SEE............................................... 455

OLV ............................................. 209

PPU.............................................. 749

SFD .............................................. 739

OMC............................................ 423

PSI................................................ 147

SFG .............................................. 687

OMG............................................ 301

PSO.............................................. 453

SFO .............................................. 441

OMH ........................................... 697

PSQ.............................................. 187

SGM............................................. 211

OMI ............................................. 447

PSR .............................................. 49

SIA ............................................... 575

OMP ............................................ 675

PSU .............................................. 367

SIC ............................................... 321

OOE............................................. 455

PTA.............................................. 323

SLD.............................................. 351

OPA............................................. 155

PTS............................................... 631

SLE............................................... 51

OPE.............................................. 331

PVL.............................................. 221

SLI................................................ 215

OPU............................................. 483

PXS .............................................. 313

SLL............................................... 551

ORI .............................................. 87

PYX.............................................. 513

SLY .............................................. 323

ORN ............................................ 637

QUA ............................................ 107

SMA............................................. 677

ORS.............................................. 635

RBO ............................................. 373

SMV............................................. 665

OSD ............................................. 335

RDR ............................................. 779

SOA ............................................. 607

OSE.............................................. 707

RER.............................................. 439

SOL.............................................. 315

OTH............................................. 255

RHC............................................. 219

SOP.............................................. 555

OUR............................................. 349

RLM............................................. 653

SOS .............................................. 731

819

Index

Code

Page

Code

Page

Code

Page

SPE............................................... 315

TOD............................................. 383

XCA............................................. 303

SPG .............................................. 247

TOL.............................................. 357

XCB.............................................. 395

SPH.............................................. 421

TOU............................................. 351

XCD............................................. 593

SPI................................................ 591

TPE .............................................. 279

XCS.............................................. 71

SSE............................................... 383

TPG.............................................. 135

XDR ............................................. 791

SSG .............................................. 169

TPS............................................... 247

XHE ............................................. 769

SSH .............................................. 769

TPY .............................................. 499

XHY............................................. 509

STA.............................................. 599

TSB............................................... 123

XIE ............................................... 469

STS............................................... 603

TSC .............................................. 431

XIN .............................................. 541

SUR.............................................. 787

TSM ............................................. 489

XIP ............................................... 291

SUT.............................................. 201

TSR .............................................. 175

XLU ............................................. 529

SZC.............................................. 67

TSX .............................................. 487

XRI............................................... 687

SZE .............................................. 457

TTA.............................................. 447

XSA.............................................. 709

SZP .............................................. 785

TTB .............................................. 391

XUM ............................................ 661

TAG ............................................. 301

TTR .............................................. 537

XVI............................................... 499

TAH............................................. 717

TTT .............................................. 463

XXL.............................................. 213

TAR ............................................. 623

TUM ............................................ 369

YDR ............................................. 327

TAT.............................................. 633

TZA ............................................. 183

YOP ............................................. 403

TCA ............................................. 341

UCA............................................. 285

ZBO ............................................. 407

TCB.............................................. 389

UMS............................................. 303

ZCA............................................. 691

TCD ............................................. 217

UPA ............................................. 155

ZCS.............................................. 271

TDE.............................................. 235

UPV ............................................. 229

ZCY ............................................. 241

TEI ............................................... 467

URS.............................................. 105

ZEV.............................................. 359

TEL .............................................. 173

UYL ............................................. 319

ZLO ............................................. 223

TER .............................................. 461

VAC............................................. 795

ZPA ............................................. 135

TFE .............................................. 473

VCT ............................................. 393

ZPE .............................................. 165

THC ............................................. 439

VOL ............................................. 111

ZPH ............................................. 189

THP ............................................. 481

XAR ............................................. 609

ZPI ............................................... 595

TLE .............................................. 353

XAU............................................. 313

ZSE .............................................. 645

820

Index

In order of IAU Name Name

Page

A1-Taurids................................. 629 A2-Taurids................................. 629 A-Carinids ................................. 789 alpha-Antliids ........................... 667 alpha-Camelopardalids ........... 325 alpha-Canis Majorids............... 495 alpha-Capricornids................... 69 alpha-Centaurids ...................... 531 alpha-Coronae Borealids......... 401 alpha-Corvids ........................... 521 alpha-Crucids............................ 523 alpha-Hydrids........................... 331 alpha-Lacertids ......................... 273 alpha-Lyncids............................ 377 alpha-Monocerotids ................. 493 alpha-Sagittariids...................... 179 alpha-Scorpiids ......................... 553 alpha-Sculptorids...................... 425 alpha-Virginids ......................... 721 Andromedids ............................ 741 Apodids ..................................... 529 April 102-Herculids ................. 245 April alpha-Capricornids ........ 139 April beta-Aquariids................ 129 April beta-Herculids ................ 239 April epsilon-Delphinids......... 235 April kappa-Cygnids ............... 773 April lambda-Ophiuchids....... 49 April Lyrids............................... 53 April phi-Capricornids ............ 417 April rho-Cygnids.................... 249 April theta-Centaurids ............ 543 April zeta-Cygnids................... 141 Arids........................................... 757

Name

Page

August gammaCamelopardalids ...................... 297 August Aquariids..................... 571 August Caelids ......................... 195 August delta-Capriconids....... 579 August Draconids .................... 79 August gamma-Cepheids ....... 307 August gamma-Pegasids ........ 289 August iota-Cetids ................... 583 August Lyncids ........................ 309 August mu-Perseids ................ 311 August nu-Eridanids ............... 443 August nu-Perseids.................. 305 August nu-Taurids................... 443 August omicron-Aquariids..... 577 August phi-Pegasids................ 293 August psi-Aurigids ................ 305 August Ursae Majorids ........... 303 August xi-Cassiopeiids............ 293 Aurigids ..................................... 81 beta-Aquariids .......................... 149 beta-Bootids............................... 393 beta-Carinids............................. 785 beta-Cassiopeids....................... 285 beta-Cepheids ........................... 307 beta-Comae Berenicids ............ 129 beta-Equuleids .......................... 183 beta-Hydrusids ......................... 755 beta-Leonids.............................. 333 beta-Pegasids............................. 141 beta-Pyxidids ............................ 761 beta-Tucanids............................ 767 Caelids ....................................... 479 Camelopardalids ...................... 159

Name

Page

c-Andromedids ......................... 265 chi1-Hydrids.............................. 527 chi-Andromedids...................... 309 chi-Aquilids ............................... 233 chi-Cancrids .............................. 321 chi-Cygnids ............................... 83 chi-Pegasids............................... 257 chi-Phoenicids ........................... 429 chi-Taurids................................. 91 chi-Virginids.............................. 507 Comae Berenicids..................... 379 Corvids....................................... 725 c-Velids ...................................... 513 Daytime April Piscids ............. 675 Daytime Arietids ...................... 61 Daytime beta-Taurids.............. 167 Daytime Capricornids-Sagitt .. 713 Daytime chi-Capricornids....... 711 Daytime Craterids.................... 689 Daytime kappa-Leonids.......... 693 Daytime kappa-Aquariids ...... 673 Daytime lambda-Pegasids ...... 679 Daytime lambda-Taurids ........ 681 Daytime pi-Leonids ................. 697 Daytime Sexantids ................... 85 Daytime Triangulids................ 157 Daytime xi-Orionids ................ 687 Daytime xi-Saggittariids.......... 709 Daytime zeta-Cancrids ............ 691 Daytime zeta-Perseids ............. 165 December alpha-Antliids ........ 505 December alpha-Bootids ......... 375 December alpha-Draconids .... 799 December alpha-Lyncids......... 651

821

Index

Name

Page

Name

Page

Name

Page

December Canis Minorids ...... 647

epsilon-Sextantids..................... 497

gamma-Lyrids........................... 403

December chi-Virginids........... 499

epsilon-Triangulids .................. 295

gamma-Pegasids....................... 299

1

December epsilon-Virginids ... 387

eta -Coronae Australids .......... 551

gamma-Piscis Austrinids ........ 421

December kappa-Draconids ... 795

eta-Andromedids...................... 589

gamma-Sagittariids .................. 415

December Lyncids.................... 369

eta-Aquariids............................. 55

gamma-Ursae Majorids........... 371

December Monocerotids ......... 641

eta-Arids .................................... 507

gamma-Ursae Minorids .......... 113

December omega-Hydrids...... 649

eta-Corvids ................................ 525

Geminids ................................... 101

December phi-Cassiopeiids .... 743

eta-Draconids ............................ 803

h-Virginids................................. 151

December psi-Ursae Majorids 375

eta-Eridanids ............................. 445

iota1-Librids............................... 547

December psi-Velids ................ 501

eta-Hydrids ............................... 503

iota2- Fornacids......................... 433

December rho-Geminids ......... 643

eta-Lyrids................................... 57

iota-Centaurids ......................... 525

December rho-Virginids.......... 365

eta-Microscopiids ..................... 427

iota-Hydrusids .......................... 781

December Sextantids ............... 505

eta-Ophiuchids.......................... 233

iota-Lupids ................................ 705

December sigma-Virginids ..... 385

eta-Orionids............................... 469

iota-Serpentids .......................... 385

December zeta-Bootids............ 387

eta-Sculptorids .......................... 435

iota-Volantids............................ 783

delta -Canis Minorids.............. 663

eta-Virginids.............................. 125

Jan. gamma-Camelopardalids 745

delta-Arietids ............................ 621

Feb. beta-Comae Berenicids ... 399

January 15-Bootids ................... 397

delta-Chamaleontids ................ 535

February alpha-Corvids .......... 535

January beta-Craterids............. 519

delta-Doradids .......................... 803

February beta-Herculids ......... 401

January eta-Draconids ............. 391

delta-Herculids ......................... 239

February delta-Cygnids .......... 231

January Hydrids....................... 517

delta-Horologiids...................... 199

February epsilon-Virginids ..... 381

January lambda-Leonids ......... 649

delta-Mensids............................ 47

February eta-Draconids........... 115

January Leonids........................ 653

delta-Normids........................... 537

February gamma-Virginids .... 669

January mu-Hydrids................ 219

delta-Pavonids .......................... 413

February Herculids .................. 405

January mu-Velorids................ 221

delta-Piscids .............................. 171

February Hydrids..................... 763

January xi-Ursae Majorids ...... 661

epsilon-Aquariids ..................... 573

February mu-Virginids............ 407

January zeta-Leonids ............... 223

epsilon-Aquilids ....................... 59

f-Herculids................................. 231

July 77-Pegasids........................ 275

epsilon-Canis Majorids............ 491

Fornacids ................................... 435

July alpha-Camelopardalids ... 287

epsilon-Draconids..................... 153

f-Taurids .................................... 613

July beta-Pegasids .................... 179

epsilon-Geminids...................... 339

gamma-Aquilids....................... 251

July eta-Pegasids ...................... 287

epsilon-Gruids .......................... 431

gamma-Crucids ........................ 119

July gamma-Draconids............ 193

epsilon-Microscopiids .............. 425

gamma-Delphinids................... 263

July kappa-Velids..................... 753

epsilon-Monocerotids .............. 461

gamma-Doradids...................... 783

July omega-Piscids ................... 289

epsilon-Ophiuchids .................. 549

gamma-Draconids .................... 773

July omicron-Pavonids ............ 753

epsilon-Pegasids ....................... 185

gamma-Geminids ..................... 685

July Pegasids............................. 281

epsilon-Perseids ........................ 683

gamma-Gruids.......................... 571

July Phoenicids ......................... 189

1

822

Index

Name

Page

Name

Page

Name

Page

July Taurids............................... 685

Leonis Minorids........................ 345

November alpha-Corvids ....... 497

July theta-Perseids.................... 279

March 12-Bootids ..................... 229

November eta-Taurids ............ 625

July xi-Arietids.......................... 437

March beta-Equuleids.............. 131

November gamma-Bootids..... 363

June Aquariids.......................... 187

March Centaurids .................... 411

November Hydrids.................. 489

June beta-Pegasids ................... 267

March epsilon-Pegasids........... 163

November i-Draconids ............ 797

June Bootids .............................. 723

May beta-Aquariids ................. 261

November lamba-Velids ......... 211

June delta-Pavonids ................. 751

May beta-Capricornids............ 253

November Orionids ................. 639

June epsilon-Arietids ............... 163

May gamma-Virginids ............ 549

November Puppids.................. 209

June epsilon-Cygnids............... 63

May kappa-Aquariids ............. 423

November sigma-Bootids ....... 357

June epsilon Gruids ................. 427

May Lacertids ........................... 243

November theta-Aurigids....... 645

June epsilon-Ophiuchids......... 559

May Microscopiids................... 429

November zeta-Perseids ......... 645

June epsilon-Serpentids........... 727

May psi-Scorpiids..................... 259

nu-Arietids ................................ 269

June eta-Eridanids.................... 433

Microscopiids............................ 561

nu-Cygnids................................ 241

June iota-Pegasids .................... 265

mu-Hydrids............................... 527

nu-Eridanids.............................. 449

June mu-Cassiopeiids .............. 261

mu-Perseids............................... 291

nu-Pegasids ............................... 245

June mu-Pegasids..................... 257

mu-Velids .................................. 501

nu-Piscids .................................. 605

June rho-Cygnids ..................... 63

mu-Virginids ............................. 545

nu-Taurids ................................. 195

June rho-Draconids .................. 781

N. Daytime May Arietids ....... 677

Oct. alpha-Comae Berenicids . 699

June theta -Sagittariids ............ 181

N. Daytime omega-Cetids ...... 143

Oct. alpha-Ursae Minorids ..... 349

June theta-Serpentids............... 557

N. March gamma-Virginids ... 665

Oct. beta-Camelopardalids ..... 733

June xi -Sagittariids.................. 563

Normids..................................... 533

Oct. epsilon-Monocerotids...... 481

kappa-Craterids ........................ 519

Northern chi-Aquariids........... 583

Oct. gamma-Camelopardalids 325

kappa-Cygnids.......................... 197

Northern chi-Orionids ............. 637

Octantids.................................... 147

kappa-Delphinids..................... 565

Northern delta-Aquariids ....... 581

October 44-Hydrids ................. 467

kappa-Orionids......................... 485

Northern delta-Cancrids ......... 655

October 6-Draconids................ 335

kappa-Serpentids...................... 237

Northern delta-Piscids............. 587

October Aurigids...................... 343

kappa-Ursae Majorids ............. 355

Northern iota-Aquariids ......... 585

October Camelopardalids ....... 329

kappa-Velids ............................. 511

Northern June Aquilids........... 65

October Capricornids .............. 731

lambda-Bootids......................... 389

Northern Librids ...................... 215

October Cetids .......................... 593

lambda-Cetids........................... 611

Northern May Opiuchids ....... 555

October delta-Sextantids ......... 485

lambda-Sagittariids .................. 557

Northern Oct. delta-Arietids .. 619

October Draconids ................... 735

lambda-Taurids ........................ 615

Northern Taurids ..................... 601

October epsilon-Aurigids........ 343

lambda-Ursae Majorids........... 353

Nov. Comae Berenicids........... 361

October epsilon-Carinids ........ 791

lambda-Velids........................... 793

Nov. sigma-Ursae Majorids.... 363

October eta-Virginids .............. 701

lamda-Caelids ........................... 465

November A-Carinids ............. 795

October gamma-Cepheids ...... 333

Leonids....................................... 93

November alpha-Aurigids...... 371

October lambda-Velorids........ 209

2

1

823

Index

Name

Page

Name

Page

6

Name

Page

October Leporids...................... 475

pi -Orionids............................... 453

September mu-Arietids ........... 595

October mu-Hydrids ............... 697

pi-Casseiopeids......................... 299

September tau-Cetids .............. 755

October Puppids....................... 483

pi-Hydrids ................................. 515

September upsilon-Taurids..... 201

October Ursae Majorids .......... 337

pi-Perseids ................................. 311

September Ursae Majorids ..... 787

October xi-Perseids .................. 331

pi-Puppids ................................. 749

September xi-Perseids.............. 313

October zeta-Perseids .............. 347

Piscis Austrinids....................... 569

September zeta-Eridanids ....... 457

omega-Capricornids................. 423

Pixidids ...................................... 513

September zeta-Puppids ......... 785

omega-Carinids ........................ 523

1

September-October Lyncids ... 315

3

psi -Piscids ................................ 147

omega-Herculids ...................... 237

psi -Aquariids ........................... 187

Serpentids-Coronae Borealids 397

omega-Hydrids......................... 479

psi-Andromedids...................... 263

sigma-Capriconids ................... 567

omega-Leonids.......................... 659

psi-Cassiopeiids ........................ 277

sigma-Columbids ..................... 475

omega-Serpentids ..................... 707

psi-Cygnids ............................... 255

sigma-Fornacids........................ 441

omega-Taurids .......................... 617

psi-Ursae Majorids ................... 367

sigma-hydrids ........................... 99

omicron -Eridanids .................. 455

psi-Velids ................................... 221

sigma-Leonids........................... 51

omicron-Aquariids ................... 171

p-Taurids ................................... 631

sigma-Pegasids ......................... 247

omicron-Aurigids ..................... 295

Quadrantids .............................. 107

sigma-Phoenicids...................... 421

omicron-Cetids ......................... 447

rho-Bootids ................................ 373

sigma-Serpentids ...................... 383

omicron-Columbids ................. 471

rho-Centaurids.......................... 219

Southern chi-Orionids ............. 635

omicron-Cygnids...................... 191

rho-Draconids ........................... 779

Southern delta-Aquariids........ 71

omicron-Draconids................... 779

rho-Eridanids ............................ 439

Southern delta-Cancrids.......... 657

omicron-Eridanids.................... 207

rho-Orionids.............................. 463

Southern delta-Piscids ............. 591

omicron-Geminids.................... 301

rho-Phoenicids .......................... 149

Southern iota-Aquariids.......... 575

omicron-Hydrids ...................... 117

rho-Piscids ................................. 593

Southern June Aquilids ........... 67

omicron-Leonids....................... 663

rho-Puppids............................... 491

Southern lambda-Draconids... 351

omicron-Pavonids .................... 155

R-Leonis Minorids.................... 653

Southern Librids....................... 215

omicron-Perseids ...................... 331

R-Lyrids ..................................... 775

Southern Librids-Lupids ......... 551

omicron-Piscids......................... 675

r-Puppids ................................... 509

Southern May Ophiuchids ..... 555

omicron-Virginids .................... 699

S. Daytime May Arietids ........ 677

Southern mu-Sagittariids ........ 169

Orionids ..................................... 87

S. Daytime omega-Cetids ....... 145

Southern Oct. delta-Arietids... 607

Perseids ...................................... 75

S. March gamma-Virginids..... 665

Southern Taurids...................... 599

phi-Cancrids.............................. 327

Sept. epsilon-Columbids ......... 473

s-Taurids .................................... 603

phi-Leonids ............................... 487

September 72-Ophiuchids....... 731

tau4-Eridanids ........................... 461

phi-Piscids ................................. 283

September epsilon-Perseids .... 315

tau9-Eridanids ........................... 467

phi-Serpentids........................... 49

September gamma-Eridanids . 457

tau-Arietids ............................... 623

phi-Taurids................................ 323

September iota-Cassiopeiids... 321

tau-Cancrids .............................. 341

Phoenicids ................................. 759

September Lyncids................... 323

tau-Herculids ............................ 717

1

824

Index

Name

Page

Name

Page

Name

Page

tau-Sculptorids.......................... 431

xi-Perseids.................................. 291

29-Piscids ................................... 477

tau-Taurids ................................ 633

Y-Draconids............................... 327

31-Pegasids................................ 135

Telescopiids ............................... 173

Y-Ophiuchids ............................ 403

31-Ursae Majorids .................... 351

theta Coronae Borealids.......... 389

zeta-Bootids............................... 407

32-Cassiopeiids ......................... 279

theta-Aurigids ........................... 301

zeta-Cassiopeiids ...................... 271

35-Eridanids .............................. 473

theta-Carinids ........................... 217

zeta-Cygnids ............................. 241

35-Vulpeculids .......................... 139

theta-Cetids ............................... 439

zeta-Pavonids............................ 135

43-Cassiopeiids ......................... 297

theta-Leonids............................. 353

zeta-Phoenicids ......................... 189

43-Leonis Minorids .................. 359

theta-Pyxidids ........................... 499

zeta-Piscids................................ 595

47-Ophiuchids........................... 405

theta-Serpentids ........................ 175

zeta-Virginids............................ 359

49-Andromedids....................... 275

theta-Trianguli Australids....... 537

2-Pegasids.................................. 247

52-Pegasids................................ 267

theta-Ursae Majorids ............... 369

3-Puppids................................... 481

56-Cetids .................................... 459

upsilon -Cassiopeiids............... 285

6-Corvids ................................... 517

58-Ophiuchids........................... 709

upsilon-Ophiuchids.................. 383

10-Canum Venaticids .............. 393

59-Cygnids ................................ 729

upsilon-Virginids...................... 229

10-Leonis Minorids .................. 651

62-Andromedids....................... 203

Ursids ......................................... 105

12-Taurids.................................. 447

62-Sagittariids ........................... 713

UY-Lyncids................................ 319

13-Delphinids............................ 235

63-Aurigids................................ 361

Volantids.................................... 111

13-Taurids.................................. 463

63-Cygnids ................................ 269

x-Herculids ................................ 769

1

14-Canum Venaticids .............. 399

64-Draconids ............................. 739

1

14-Orionids................................ 597

68-Geminids .............................. 211

2

15-Bootids .................................. 717

68-Virginids............................... 543

2

15-Leonids ................................. 367

74-Geminids .............................. 687

2

xi -Lupids .................................. 529

17-Eridanids .............................. 455

77-Cetids .................................... 441

xi-Arietids .................................. 609

20-Aquariids.............................. 183

77-Herculids .............................. 769

xi-Aurigids................................. 313

22-Bootids .................................. 391

80-Virginids............................... 223

xi-Cassiopeiids .......................... 303

23 Ophiuchids........................... 155

87-Virginids............................... 541

xi-Coronae Borealids................ 395

25-Sextantids ............................. 487

90-Herculids .............................. 775

xi-Draconids .............................. 791

26-Bootids .................................. 123

110-Herculids ............................ 255

xi-Eridanids ............................... 469

27-Monocerotids ....................... 489

xi-Hydrids ................................. 509

28-Lyncids ................................. 357

xi -Centaurids ........................... 541 xi -Capricornids........................ 71 xi -Librids .................................. 213