Comets Section Blog
Summary
The comet of the moment is C/2017 K2 (PANSTARRS). Currently around 8th magnitude, C/2017 K2 has become an interesting object for both visual and imaging observers. While K2 is visible from both hemispheres, the second brightest comet of the month, C/2021 E3 (ZTF) at 9-10th magnitude, is solely a southern hemisphere object. A number of fainter comets are in the 10th to 13th magnitude range, including 22P/Kopff, 73P/Schwassmann-Wachmann, 169P/NEAT, C/2019 L3 (ATLAS), C/2019 T4 (ATLAS), C/2020 V2 (ZTF), C/2021 P4 (PANSTARRS), and C/2022 E3 (ZTF). C/2022 E3 is still looking like it will become a nice borderline naked eye object in 2023.
In June the ALPO Comets Section received 52 magnitude estimates and 34 images/sketches of comets C/2022 L2 (ATLAS), C/2022 E3 (ZTF), C/2021 P4 (ATLAS), C/2021 F1 (Lemmon-PANSTARRS), C/2021 E3 (ZTF), C/2021 A1 (Leonard), C/2020 V2 (ZTF), C/2020 R7 (ATLAS), C/2020 K1 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2017 K2 (PANSTARRS), 337P/WISE, 327P/Van Ness, 325P/Yang-Gao, 287P/Christensen, 117P/Helin-Roman-Alu, 116P/Wild, 73P/Schwassmann-Wachmann, 45P/Honda-Mrkos-Pajdusakova, 22P/Kopff, and 12P/Pons-Brooks. A big thanks to our recent contributors: Dan Bartlett, John Chumack, J. J. Gonzalez, Christian Harder, Carl Hergenrother, Eliot Herman, Michael Jäger, John Maikner, Martin Mobberley, Michael Phillips, Uwe Pilz, Raymond Ramlow, Michael Rosolina, Gregg Ruppel, John D. Sabia, Chris Schur, Tenho Tuomi, and Chris Wyatt.
In addition to observations submitted directly to the ALPO, we occasionally use data from other sources to augment our analysis. We would like to acknowledge with thanks observations submitted directly to the ALPO as well as those originally submitted to the International Comet Quarterly, Minor Planet Center, and COBS Comet Observation Database. We would also like to thank the Jet Propulsion Laboratory for making available their Small-Body Browser and Orbit Visualizer and Seiichi Yoshida for his Comets for Windows programs that are used to produce the lightcurves and orbit diagrams in these pages. And last but not least, we’d like to thank Syuichi Nakano and the Minor Planet Center for their comet orbit elements, the asteroid surveys and dedicated comet hunters for their discoveries, and all of the observers who volunteer their time to adding to our knowledge of these amazing objects.
The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.
Summary
To borrow from Mark Twain, the reports of C/2021 O3 (PANSTARRS)’s demise was an exaggeration. The comet is much fainter than hoped for at 12th magnitude but well placed for northern observers. While C/2021 O3 did not become the bright object we expected, another comet, 45P/Honda-Mrkos-Pajdusakova, is running about 3 magnitudes brighter than expected (starting around 8th magnitude and fading to 10th this month) low in the evening sky. Two other comets will be brighter than 10th magnitude in June, C/2021 E3 (ZTF0 but only observable from the southern hemisphere, and C/2017 K2 (PANSTARRS) which is visible to all. In the magnitude 10 to 13 range are no less than 9 comets, 19P/Borrelly, 22P/Kopff, 169P/NEAT, C/2019 L3 (ATLAS), C/2019 T4 (ATLAS), C/2020 V2 (ZTF), C/2021 E3 (ZTF). C/2021 F1 (Lemmon-PANSTARRS), and C/2021 P4 (PANSTARRS).
In May the ALPO Comets Section received 76 magnitude estimates and 69 images/sketches of comets C/2021 P4 (ATLAS), C/2021 O3 (PANSTARRS), C/2021 E3 (ZTF), C/2021 A1 (Leonard), C/2020 Y2 (ATLAS), C/2020 V2 (ZTF), C/2020 R7 (ATLAS), C/2020 M5 (ATLAS), C/2020 K1 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 274P/Tombaugh-Tenagra, 272P/NEAT, 254P/McNaught, 244P/Scotti, 117P/Helin-Roman-Alu, 116P/Wild, 104P/Kowal, 73P/Schwassmann-Wachmann, 67P/Churyumov-Gerasimenko, 45P/Honda-Mrkos-Pajdusakova, 22P/Kopff, 19P/Borrelly, and 9P/Tempel. A hearty thanks to our April contributors: Dan Bartlett, Michel Deconinck, J. J. Gonzalez, Christian Harder, Michael Jager, Martin Mobberley, Mike Olason, Uwe Pilz, Raymond Ramlow, Tenho Tuomi, and Chris Wyatt.
In addition to observations submitted directly to the ALPO, we occasionally use data from other sources to augment our analysis. We would like to acknowledge with thanks observations submitted directly to the ALPO as well as those originally submitted to the International Comet Quarterly, Minor Planet Center, and COBS Comet Observation Database. We would also like to thank the Jet Propulsion Laboratory for making available their Small-Body Browser and Orbit Visualizer and Seiichi Yoshida for his Comets for Windows programs that are used to produce the lightcurves and orbit diagrams in these pages. And last but not least, we’d like to thank Syuichi Nakano and the Minor Planet Center for their comet orbit elements, the asteroid surveys and dedicated comet hunters for their discoveries, and all of the observers who volunteer their time to adding to our knowledge of these amazing objects.
The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.
Summary
Last month’s big question was “What’s up with C/2021 O3 (PANSTARRS)?” Would it survive passing 0.29 au from the Sun or disintegrate like many other dynamically new, intrinsically faint comets? We now have our answer. C/2021 O3 has likely disintegrated with a remnant dust cloud being all that’s remains of the comet. Still as of the end of April, some ground-based observers have been able to detect a diffuse remnant at ~9th magnitude. This at least gives us some hope of being able to monitor the slow dispersal of the dusty remains as it heads into the northern circumpolar evening sky.
Of course, C/2021 O3 isn’t the only comet in the sky. While May won’t see any very bright comets, a number will be in the 9-10th magnitude range including C/2017 K2 (PANSTARRS), C/2019 L3 (ATLAS), C/2021 E3 (ZTF), and C/2021 F1 (Lemmon-PANSTARRS) (the last two only visible from the southern hemisphere). Observers who can push fainter to around 12th magnitude can also observe 9P/Tempel, 19P/Borrelly, 22P/Kopff, 45P/Honda-Mrkos-Pajdusáková, C/2019 T4 (ATLAS), C/2020 (ZTF), and C/2021 P4 (ATLAS).
April saw the ALPO Comets Section receive 89 magnitude estimates and 15 images/sketches of comets C/2021 P4 (ATLAS), C/2021 O3 (PANSTARRS), C/2021 E3 (ZTF), C/2021 A1 (Leonard), C/2020 Y2 (ATLAS), C/2020 V2 (ZTF), C/2020 M5 (ATLAS), C/2020 K1 (PANSTARRS), C/2020 J1 (SONEAR), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 116P/Wild, 104P/Kowal, 73P/Schwassmann-Wachmann, 67P/Churyumov-Gerasimenko, 29P/Schwassmann-Wachmann, 22P/Kopff, 19P/Borrelly, and 9P/Tempel. A hearty thanks to our April contributors: Dan Bartlett, Michel Deconinck, J. J. Gonzalez, Christian Harder, Michael Jager, Mike Olason, Uwe Pilz, Raymond Ramlow, Chris Schur, and Chris Wyatt.
In addition to observations submitted directly to the ALPO, we occasionally use data from other sources to augment our analysis. We would like to acknowledge with thanks observations submitted directly to the ALPO as well as those originally submitted to the International Comet Quarterly, Minor Planet Center, and COBS Comet Observation Database. We would also like to thank the Jet Propulsion Laboratory for making available their Small-Body Browser and Orbit Visualizer and Seiichi Yoshida for his Comets for Windows programs that are used to produce the lightcurves and orbit diagrams in these pages. And last but not least, we’d like to thank Syuichi Nakano and the Minor Planet Center for their comet orbit elements, the asteroid surveys and dedicated comet hunters for their discoveries, and all of the observers who volunteer their time to adding to our knowledge of these amazing objects.
The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.
Summary
The big comet question for this month is what’s up with C/2021 O3 (PANSTARRS)? Arriving at perihelion on April 21 at a small heliocentric distance of 0.29 au, some predictions have PANSTARRS peaking at 4-5th magnitude. Unfortunately, the comet has a lot working against it. It is intrinsically faint, likely making its first passage through the inner Solar System, and when last observed back in early February was brightening at a very slow rate. All of these point to a comet that may be prone to disintegration as it nears perihelion, if it hasn’t already. Since the comet has been located a small solar elongation over the past 2 months, we don’t really know how bright it currently is. And to make things worse, it will either be unobservable or only observable deep in twilight in April.
Don’t worry if C/2021 O3 disappoints as there are plenty of other comets observable between 9th and 13th magnitude this month. C/2019 L3 (ATLAS) is at 9th magnitude and well placed in the evening sky. C/2017 K2 (PANSTARRS) continues to slowly brighten and may break the magnitude 10 level in the morning sky. Last month’s brightest comet, C/2021 F1 (Lemmon-PANSTARRS), will still be around 8th magnitude but will be too close to the Sun for most observers. Unfortunately, another 9th magnitude comet, 45P/Honda-Mrkos-Pajdusáková, will also be too close to the Sun for observation in April.
On the fainter side (between magnitude 10 and 13) we have short-period comets 9P/Tempel, 19P/Borrelly, 22P/Kopff, 29P/Schwassmann-Wachmann, 67P/Churyumov-Gerasimenko, 104P/Kowal, C/2019 T4 (ATLAS), C/2020 (ZTF), C/2021 E3 (ZTF), and C/2021 P4 (ATLAS). A few months ago, C/2021 A1 (Leonard) was dazzling comet watchers. The comet may be in the midst of its own disintegration or in the process of “turning off”. Imagers are encouraged to watch as the dusty remnant of Leonard slowly disperses.
Looking ahead to next year, recently discovered C/2022 E3 (ZTF) is currently 16th magnitude but may brighten to 5-6th magnitude next January and February.
Since the last Report was published on February 23, the ALPO Comets Section has received 161 magnitude estimates and 48 images and sketches of comets C/2021 P4 (ATLAS), C/2021 F1 (Lemmon-PANSTARRS), C/2021 E3 (ZTF), C/2020 Y2 (ATLAS), C/2020 V2 (ZTF), C/2020 U5 (PANSTARRS), C/2020 M5 (ATLAS), C/2020 J1 (SONEAR), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 116P/Wild, 108P/Ciffreo, 104P/Kowal, 67P/Churyumov-Gerasimenko, 29P/Schwassmann-Wachmann, 22P/Kopff, 19P/Borrelly, and 9P/Tempel. Observations were contributed by Dan Bartlett, Michel Deconinck, Stephane Ferier, J. J. Gonzalez, Christian Harder, Eliot Herman, Martin Mobberley, Uwe Pilz, Raymond Ramlow, Tenho Tuomi, and Chris Wyatt.
In addition to observations submitted directly to the ALPO, we occasionally use data from other sources to augment our analysis. We would like to acknowledge with thanks observations submitted directly to the ALPO as well as those originally submitted to the International Comet Quarterly, Minor Planet Center, and COBS Comet Observation Database. We would also like to thank the Jet Propulsion Laboratory for making available their Small-Body Browser and Orbit Visualizer and Seiichi Yoshida for his Comets for Windows programs that are used to produce the lightcurves and orbit diagrams in these pages. And last but not least, we’d like to thank Syuichi Nakano and the Minor Planet Center for their comet orbit elements, the asteroid surveys and dedicated comet hunters for their discoveries, and all of the observers who volunteer their time to adding to our knowledge of these amazing objects.
The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.
Summary
Well, this Comet News is either very late for February or a few days early for March. Due to delays in getting this out for February, it will cover the remainder of February and all of March.
A large number of comets are in the 8th-10th magnitude range including 19P/Borrelly, 67P/Churyumov-Gerasimenko, 104P/Kowal, and C/2019 L3 (PANSTARRS) in the evening and C/2017 K2 (PANSTARRS) and C/2021 F1 (Lemmon-PANSTARRS) in the morning sky. On a bit of the fainter side are receding 4P/Faye and 6P/d’Arrest, incoming C/2019 T4 (ATLAS) and C/2021 E3 (ZTF), and two short-period comets at perihelion 9P/Tempel and 22P/Kopff. After spending a few weeks too close to the Sun for observation, last year’s comet highlight, C/2021 A1 (Leonard), should reappear as a fainter object of ~11-12th magnitude but only for observers in the southern hemisphere.
Since January 1, the ALPO Comets Section has received 111 magnitude estimates and 61 images and sketches of comets C/2022 A1 (Sárneczky), C/2021 O3 (PANSTARRS), C/2021 F1 (Lemmon-PANSTARRS), C/2021 A1 (Leonard), C/2020 V2 (ZTF), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 430P/Scotti, 116P/Wild, 104P/Kowal, 67P/Churyumov-Gerasimenko, 29P/Schwassmann-Wachmann, 19P/Borrelly, 6P/d’Arrest and 4P/Faye. Observations were contributed by Paul G. Abel, Dan Bartlett, Michel Besson, Denis Buczynski, John Chumack, Michel Deconinck, Lukas Demetz, J. J. Gonzalez, Christian Harder, Jan Hattenbach, Carl Hergenrother, Eliot Herman, Michael Jäger, Gianluca Masi, Martin Mobberley, Michael Olason, Uwe Pilz, Ludovic Prebet, Raymond Ramlow, Tenho Tuomi, and Chris Wyatt.
In addition to observations submitted directly to the ALPO, we occasionally use data from other sources to augment our analysis. We would like to acknowledge with thanks observations submitted directly to the ALPO as well as those originally submitted to the International Comet Quarterly, Minor Planet Center, and COBS Comet Observation Database. We would also like to thank the Jet Propulsion Laboratory for making available their Small-Body Browser and Orbit Visualizer and Seiichi Yoshida for his Comets for Windows programs that are used to produce the lightcurves and orbit diagrams in these pages. And last but not least, we’d like to thank Syuichi Nakano and the Minor Planet Center for their comet orbit elements, the asteroid surveys and dedicated comet hunters for their discoveries, and all of the observers who volunteer their time to adding to our knowledge of these amazing objects.
The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.
- Carl Hergenrother