ALPO COMET NEWS FOR February-March 2022
A Publication of the Comets Section of the Association of Lunar and Planetary Observers
By Carl Hergenrother
The monthly Association of Lunar and Planetary Observers (ALPO) Comet News PDF can be found on the ALPO Comets Section website @ http://www.alpo-astr....org/cometblog/. A shorter version of this report is posted here (minus the magnitude estimates, lightcurves, images, and other figures contained in the full PDF). The ALPO Comet Section welcomes all comet related observations, whether textual descriptions, images, drawings, magnitude estimates, or spectra. You do not have to be a member of ALPO to submit material, though membership is encouraged. To learn more about the ALPO, please visit us @ http://www.alpo-astronomy.org. We can also be reached at < comets @ alpo-astronomy.org >.
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.
Aperture Corrections to Magnitude Measurements
We try to include up to date lightcurves for most of the objects discussed in this report as well as applying aperture corrections to the visual observations. All magnitude estimates are affected by many factors including instrumental (aperture, focal length, magnification, type of optics), environmental (sky brightness due to moonlight, light pollution, twilight, aurora activity, zodiacal light, etc), cometary (degree of condensation, coma color, strength and type of gas emission lines, coma-tail interface) and personal (sensitivity to different wavelengths, personal technique, observational biases). The correction used here only corrects for differences in aperture [C. S. Morris, On Aperture Corrections for Comet Magnitude Estimates. Publ Astron Soc Pac 85, 470, 1973]. Visual observations are corrected to a standard aperture of 6.78 cm by 0.019 magnitudes per centimeter for refractors and 0.066 magnitudes per centimeter for reflectors. As our work develops, we will investigate the determination of personal corrections for each observer for each individual comet as well as for digital observations
Comets Calendar for February & March 2022
Feb 01 - 19P/Borrelly at perihelion (q = 1.31 au, 6.9-yr period, V ~8, discovered in 1904, 16th observed return since discovery, target of Deep Space 1 mission, more below)
Feb 02 - C/2021 K3 (Catalina) at perihelion (q = 5.23 au, V ~ 20-21, at small elongation this month)
Feb 03 - C/2021 D2 (ZTF) at perihelion (q = 2.95 au, V ~ 16-17)
Feb 07 - 86P/Wild at perihelion (q = 2.26 au, 6.8-yr period, V ~20, discovered in 1980, should be 7th observed return since discovery, still awaiting recovery)
Feb 07 - P/2011 W1 (PANSTARRS) at perihelion (q = 3.32 au, 10.1-yr period, V ~???, discovered in 2011, first return since discovery, still awaiting recovery)
Feb 08 - First Quarter Moon
Feb 12 - 348P/PANSTARRS at perihelion (q = 2.18 au, 5.6-yr period, V ~ 18-19, discovered in 2010, 3rd observed return)
Feb 13 - 431P/Scotti at perihelion (q = 1.81 au, 6.5-yr period, V ~18-19, discovered in 2002, 3rd observed return)
Feb 14 - C/2021 L3 (Borisov) at perihelion (q = 8.46 au, V ~ 19)
Feb 15 - 97P/Metcalf-Brewington at perihelion (q = 2.57 au, 10.4-yr period, V ~ 16-17, at small elongation this month, discovered in 1906, re-discovered in 1991, 2nd observed return)
Feb 16 - Full Moon
Feb 17 - 382P/Larson at perihelion (q = 4.42 au, 16.5-yr period, V ~ 17, at small elongation this month, discovered in 2007, 5th observed return, multi-magnitude outbursts in 1991 and 2012)
Feb 22/23 - 19P within 1 deg of galaxy NGC 918
Feb 23 - Last Quarter Moon
Feb 23/24 - 19P within 0.3 deg of galaxies NGC 935 and IC 1801
Feb 24 - 19P within 0.6 deg of galaxies NGC 924, 930, and 938
Feb 24 - C/2020 R2 (PANSTARRS) at perihelion (q = 4.69 au, 8400-yr period, V ~ 17)
Feb 26 - 19P within 0.2 deg of galaxy NGC 976
Feb 26 - 9P/Tempel passes within 10’ of planetary nebula IC 4732
Mar 02 - New Moon
Mar 04 - 9P/Tempel at perihelion (q = 1.54 au, 5.6-yr period, V ~ 12, discovered in 1867, 14th observed return, target of Deep Impact and Stardust-NEXT missions, more below)
Mar 10 - First Quarter
Mar 12-13 - Mars and C/2021 E3 (ZTF) pass within 10’ of each other along our line-of-sight (they are actually 0.74 au apart).
Mar 14-15 - 6P/d’Arrest passes within arc minutes to 0.3 deg of galaxies NGC 941, 955 and 936 (sometimes called ‘Darth Vader’s Starfighter’)
Mar 16 - 19P/Borrelly passes within 0.6 deg of the emission nebula NGC 1333
Mar 18 - Full Moon
Mar 18 - 22P/Kopff at perihelion (q = 1.55 au, 6.4-yr period, V ~ 11, discovered in 1906, 18th observed return, more below)
Mar 18/19 - 104P/Kowal passes half a deg south of the emission nebula Lower’s Nebula (Sh2-261)
Mar 19 - 230P/LINEAR (q = 1.57 au, 6.4-yr period, V ~ 16-17, discovered in 2009, 5th observed return including 2 prior to discovery)
Mar 20 - 19P/Borrelly passes within ~0.3 deg of emission nebula IC 348 (omicron Persei cloud)
Mar 21-22 - 6P/d’Arrest passes within arc minutes of galaxy M77 and 0.5 deg from galaxy NGC 1055
Mar 23-24 - 19P/Borrelly passes within arc minutes of PN IC 2003
Mar 24 - Last Quarter
Mar 27 - 19P/Borrelly grazes the southeastern edge of the large California Nebula
Comets Brighter Than Magnitude 10
19P/Borrelly
Discovered 1904 December 28 by the Alphonse Borrelly
Orbit (from Minor Planet Center, MPEC 2022-C56)
19P/Borrelly
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 Feb. 1.82550 TT Rudenko
q 1.3062755 (2000.0) P Q
n 0.14400107 Peri. 351.91733 +0.38679754 -0.79276740
a 3.6048918 Node 74.24701 +0.87108458 +0.14644908
e 0.6376381 Incl. 29.30470 +0.30265379 +0.59166926
P 6.84
From 1044 observations 2015 Jan. 11-2022 Feb. 2, mean residual 0".7.
Nongravitational parameters A1 = -0.00, A2 = -0.2608.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
19P/Borrelly Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 02 18 +17 47 1.326 1.368 66E Ari 8.7 47 8
2022-Feb-26 02 32 +20 51 1.338 1.401 65E Ari 8.8 47 6
2022-Mar-03 02 47 +23 45 1.352 1.437 64E Ari 9.0 46 4
2022-Mar-08 03 02 +26 29 1.368 1.475 63E Ari 9.1 46 3
2022-Mar-13 03 18 +29 01 1.387 1.515 63E Ari 9.3 46 2
2022-Mar-18 03 34 +31 22 1.408 1.557 62E Per 9.5 45 1
2022-Mar-23 03 51 +33 30 1.431 1.601 61E Per 9.7 44 0
2022-Mar-28 04 09 +35 25 1.455 1.648 61E Per 10.0 44 0
2022-Apr-02 04 27 +37 07 1.481 1.696 60E Per 10.2 43 0
Comet Magnitude Formula & Lightcurve (from ALPO and COBS photometry)
m1 = 5.3 + 5 log d + 22.0 log r
where “t” is date of perihelion, “d” is Comet-Earth distance in au, and “r” is Comet-Sun distance in au
This year’s apparition of comet 19P/Borrelly is its 16th observed return. Its best recent returns were in 1987 and 1994 with approaches to 0.48 and 0.62 au of Earth when the comet reached magnitude 7.0 to 7.5. 2022 begins a new series of good apparitions. Though still a distant 1.17 au from Earth at its closest this time around, it will come closer in 2028 (0.41 au), 2035 (0.62 au), 2042 (1.13 au), 2084 (1.12 au), 2091 (0.87 au) and 2097 (0.63 au). The next return in 2028 will be Borrelly’s best between 1900 and 2100.
Borrelly is well placed for northern observers in the evening sky as its moves through Pisces (Feb 1-8), Aries (Feb 8-Mar 16), Taurus (Mar 16-17) and Perseus (Mar 17-31). It is a very low object for southern hemisphere observers over the coming weeks.
The comet has spent most of January and February near a peak brightness of around magnitude 8.5. Visual observers have found the comet to possess a moderately condensed coma with a diameter between 2 and 8’. Digital observers such as Raymond Ramlow have measured an even larger 12’ coma. Both visual and digital observers have measured a tail with a length up to 8.5’ (visual by Michel Deconinck) and >40’ (Ramlow).
With perihelion on February 1 at 1.31 au and also past a close approach to Earth back on December 11 at 1.17 au, Borrelly will be fading to magnitude 8.9 on March 1 and 10.1 on April 1.
67P/Churyumov-Gerasimenko
Discovered 1969 September 11 by the Klim Ivanovic Churyumov and Svetlana Ivanovna Gerasimenko
Orbit (from Minor Planet Center, MPEC 2022-C234)
67P/Churyumov-Gerasimenko
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2021 Nov. 2.06610 TT Rudenko
q 1.2106353 (2000.0) P Q
n 0.15341013 Peri. 22.13754 +0.52344257 -0.85112130
a 3.4559440 Node 36.33326 +0.77128094 +0.45334084
e 0.6496947 Incl. 3.87162 +0.36212373 +0.26471609
P 6.42
From 9780 observations 1995 July 3-2022 Feb. 13, mean residual 0".8.
Nongravitational parameters A1 = +0.08, A2 = +0.0111.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
67P/Churyumov-Gerasimenko Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 08 23 +27 25 1.785 0.864 148E Cnc 10.7 77 23
2022-Feb-26 08 23 +26 58 1.824 0.927 144E Cnc 10.9 77 23
2022-Mar-03 08 24 +26 28 1.863 0.994 139E Cnc 11.2 76 24
2022-Mar-08 08 26 +25 58 1.902 1.065 135E Cnc 11.5 76 24
2022-Mar-13 08 29 +25 26 1.942 1.139 130E Cnc 11.8 75 25
2022-Mar-18 08 32 +24 54 1.981 1.217 126E Cnc 12.0 75 25
2022-Mar-23 08 35 +24 21 2.021 1.298 122E Cnc 12.3 74 26
2022-Mar-28 08 40 +23 47 2.061 1.382 119E Cnc 12.6 74 26
2022-Apr-02 08 44 +23 13 2.100 1.468 115E Cnc 12.8 73 27
Comet Magnitude Formula & Lightcurve (from ALPO and COBS data)
m1 = 9.1 + 5 log d + 12.6 log r(t-52)
where “t” is date of perihelion, “d” is Comet-Earth distance in au, and “r” is Comet-Sun distance in au
67P was discovered on photographic plates taken on 1969 September 11 by Kiev University Astronomical Observatory astronomers Klim Ivanovic Churyumov and Svetlana Ivanovna Gerasimenko working at the Alma-Ata Astrophysical Institute in current day Kazakhstan. The current apparition is 67P’s 9th observed return with perihelion occurring back on 2021 November 2 at 1.21 au and closest approach to Earth at 0.42 au on November 12. The close approach makes this the comet’s best return since 1982 when it came marginally closer to Earth at 0.39 au. This is also the best apparition throughout the remainder of the century though there will be similar close approaches to Earth in 2034 (0.45 au), 2067 (0.44 au), and 2080 (0.49 au).
Now months after its November perihelion, 67P is a fading evening sky object (all month in Cancer). Its peak brightness appeared to have occurred in December around magnitude 8.5. Visual observers recently measured a coma 3 to 5’ in diameter with imagers still tracing a tail up to nearly a degree in length. In mid-February it will be around magnitude 10.5, though fading to 11 by March 1 and close to 13 by the end of March.
104P/Kowal
Photographically discovered on 1979 January 27 by Charles Kowal at Palomar Observatory
Orbit (from Minor Planet Center, MPEC 2022-C234)
104P/Kowal
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 Jan. 11.62552 TT Rudenko
q 1.0730252 (2000.0) P Q
n 0.17172988 Peri. 227.25577 +0.26936620 -0.96196575
a 3.2055715 Node 207.21647 +0.91004789 +0.26969309
e 0.6652624 Incl. 5.70052 +0.31504712 +0.04344566
P 5.74
From 966 observations 2016 Jan. 3-2022 Feb. 13, mean residual 0".9.
Nongravitational parameters A1 = -0.18, A2 = -1.9304.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
104P/Kowal Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 04 09 +10 40 1.204 0.679 90E Tau 9.7 58 30
2022-Feb-26 04 35 +11 54 1.234 0.707 91E Tau 10.0 59 30
2022-Mar-03 04 59 +12 57 1.267 0.740 92E Ori 10.4 60 31
2022-Mar-08 05 23 +13 49 1.302 0.779 93E Ori 10.8 60 31
2022-Mar-13 05 45 +14 28 1.339 0.823 94E Ori 11.3 61 32
2022-Mar-18 06 07 +14 57 1.376 0.873 94E Ori 11.8 61 32
2022-Mar-23 06 27 +15 16 1.415 0.927 94E Ori 12.2 60 33
2022-Mar-28 06 47 +15 26 1.455 0.985 94E Gem 12.7 60 33
2022-Apr-02 07 05 +15 28 1.496 1.048 93E Gem 13.2 59 33
Comet Magnitude Formula (from ALPO and COBS data)
m1 = 9.1 + 5 log d + 30.7 log r(t-18)
where “t” is date of perihelion, “d” is Comet-Earth distance in au, and “r” is Comet-Sun distance in au
Short-period comet 104P/Kowal was discovered on 1979 January 27, 28, and 29 at 17th magnitude by Charles Kowal on photographic plates taken with the 1.2-m Schmidt on Mount Palomar. 104P was one of 6 periodic comets discovered by Kowal. In addition to 104P, he also found 95P/Chiron, 99P/Kowal, 134P/Kowal-Vavrova, 143P/Kowal-Mrkos, and 158P/Kowal-LINEAR. Visual comet discoverer Reverend Leo Boethin of the Philippines observed an outburst of 104P in 1973 though it faded before his discovery could be confirmed.
The perihelion distance of 104P has decreased since its original sighting in 1973 from 1.53 to its current 1.07 au. An approach to 0.62 au of Jupiter in 2031 will result in another decrease to 0.98 au at its 2033 return. The current return will see 104P’s smallest observed distance to Earth at 0.64 au. Even closer approaches are possible during the remainder of the century in 2039 (0.40 au), 2049 (0.25 au), 2060 (0.07 au), 2071 (0.39 au), 2082 (0.59 au), and 2093 (0.31 au). As a result, 104P may become a routine small telescope object in the future.
104P is also passed its perihelion and has likely started fading. Around magnitude 9.5 in mid-February, it should fade to magnitude 10.0 in late Feb, 11.0 in early March, 12.0 in mid to late March. Kowal is visible from both hemispheres as it moves through Cetus (Feb 1-12), Taurus (12-28), Orion (28-Mar 13), back to Taurus (13-15), Orion again (15-23) and Gemini (23-31) in the evening sky. Observers in January and February found a somewhat condescend coma 5-8’ in diameter. Imagers found the coma to be even larger at 11’.
C/2017 K2 (PANSTARRS)
Discovered 2017 May 21 by the Pan-STARRS survey with the Pan-STARRS1 1.8-m on Haleakala
Dynamically new long-period comet
Orbit (from MPEC 2022-C234)
C/2017 K2 (PANSTARRS)
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 Dec. 19.69271 TT Rudenko
q 1.7971148 (2000.0) P Q
z -0.0003888 Peri. 236.19338 +0.01825454 +0.04925455
+/-0.0000007 Node 88.23673 -0.18101565 +0.98244339
e 1.0006987 Incl. 87.55886 -0.98331079 -0.17994159
From 7179 observations 2013 May 12-2022 Feb. 11, mean residual 0".4.
1/a(orig) = -0.000031 AU**-1, 1/a(fut) = +0.001161 AU**-1.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
C/2017 K2 (PANSTARRS) Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022 Feb 21 18 36 +12 20 3.937 4.356 58M Oph 10.2 38 8
2022 Feb 26 18 39 +11 18 3.892 4.258 61M Oph 10.2 40 12
2022 Mar 03 18 42 +11 18 3.847 4.156 65M Oph 10.1 41 16
2022-Mar-08 18 45 +11 20 3.802 4.052 68M Oph 10.0 43 20
2022-Mar-13 18 47 +11 22 3.756 3.944 71M Aql 9.9 45 24
2022-Mar-18 18 49 +11 25 3.711 3.834 75M Aql 9.8 46 27
2022-Mar-23 18 51 +11 29 3.665 3.722 79M Aql 9.7 48 30
2022-Mar-28 18 53 +11 33 3.620 3.609 82M Aql 9.6 49 32
2022-Apr-02 18 54 +11 37 3.575 3.493 86M Aql 9.5 51 35
Comet Magnitude Formula (from ALPO and COBS data)
m1 = 2.7 + 5 log d + 7.3 log r
C/2017 K2 (PANSTARRS) was discovered back on 2017 May 21 by the Pan-STARRS1 1.8-m telescope at Haleakala on the Hawaiian island of Maui. At discovery the comet was around 21st magnitude and located at 16.1 au from the Sun. Pre-discovery observations were found back to May of 2013 when the comet was 23.7 au from the Sun which is further than the distance of Uranus.
Even though it was discovered over nearly 3 years ago, perihelion isn’t till 2022 December 19 at 1.80 au. In contrast to some recent comets, C/2017 K2 has brightened at a steady rate back to at least 2018. If that rate continues, it should brighten above magnitude 10.0 by early to mid-March as it moves through Ophiuchus (Feb 1-March 8) and Aquila (March 8-31) in the morning sky.
C/2019 L3 (ATLAS)
Discovered 2019 June 10 by the ATLAS survey with one of their 0.5-m f/2 Schmidt
Orbit (from Minor Planet Center, MPEC 2022-C234)
C/2019 L3 (ATLAS)
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 Jan. 9.62407 TT Rudenko
q 3.5544798 (2000.0) P Q
z -0.0004440 Peri. 171.61167 -0.26052878 -0.66630389
+/-0.0000003 Node 290.78995 +0.83676453 +0.20516665
e 1.0015781 Incl. 48.36123 +0.48161175 -0.71690011
From 4036 observations 2019 June 10-2022 Feb. 11, mean residual 0".4.
1/a(orig) = +0.000111 AU**-1, 1/a(fut) = -0.000872 AU**-1.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
C/2019 L3 (ATLAS) Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 06 35 +22 50 3.575 2.902 126E Gem 8.9 73 27
2022-Feb-26 06 34 +21 55 3.580 2.969 120E Gem 9.0 72 28
2022-Mar-03 06 34 +21 03 3.586 3.040 115E Gem 9.1 71 29
2022-Mar-08 06 34 +20 12 3.592 3.115 111E Gem 9.1 70 29
2022-Mar-13 06 35 +19 24 3.599 3.192 106E Gem 9.2 69 30
2022-Mar-18 06 36 +18 38 3.607 3.272 101E Gem 9.2 67 30
2022-Mar-23 06 38 +17 54 3.615 3.353 97E Gem 9.3 64 31
2022-Mar-28 06 40 +17 11 3.623 3.436 92E Gem 9.4 60 31
2022-Apr-02 06 43 +16 30 3.632 3.519 88E Gem 9.4 56 31
Comet Magnitude Formula and Lightcurve (from ALPO and COBS data)
m1 = -5.8 + 5 log d + 22.7 log r [T-600 days to T-0]
m1 = 1.1 + 5 log d + 10.0 log r [T-0 and onwards, assumed]
where “t” is date of perihelion, “d” is Comet-Earth distance in au, and “r” is Comet-Sun distance in au
C/2019 L3 (ATLAS) is yet another fading comet in the evening sky. Perihelion was at the beginning of the year on 2022 January 9 at 3.55 au. The large perihelion distance means C/2019 L3 will slowly move away from the Sun and Sun and should result in a slow rate of fading.
Observations in January and February caught the comet near its peak brightness with most estimates in the magnitude 8.6 to 9.5 range. While its visual coma was rather small at 2-4’ it was consistently seen as moderately condensed with DC values of 4-6. Both visual observers and imagers detected a short tail up to 16’ in length.
C/2019 L3 (ATLAS) spends all month in Gemini and is well placed in the evening from both hemispheres. The comet followed a rapid and steady brightening rate (2.5n ~ 22.7) going back to mid-2020. The predicted magnitudes for February and March assume a slowdown in its rate of brightness to 2.5n ~ 10. If not, it may be a bit fainter than the magnitudes given above. Regardless C/2019 L3 should still be a 9th magnitude object throughout the remainder of February and March.
C/2021 F1 (Lemmon-PANSTARRS)
Discovered 2021 March 19 by the Mount Lemmon survey
Dynamically old long-period comet with ~3700-year period
Orbit (from MPEC 2022-C234)
C/2021 F1 (Lemmon-PANSTARRS)
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 Apr. 6.87351 TT Rudenko
q 0.9954890 (2000.0) P Q
z +0.0042347 Peri. 146.82231 +0.70298915 +0.60122332
+/-0.0000020 Node 203.45141 +0.23496395 +0.30785886
e 0.9957844 Incl. 107.32441 +0.67126611 -0.73739639
From 470 observations 2021 Mar. 19-2022 Feb. 13, mean residual 0".4.
1/a(orig) = +0.004927 AU**-1, 1/a(fut) = +0.004345 AU**-1.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
C/2021 F1 (Lemmon-PANSTARRS) Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 21 38 +47 27 1.250 1.432 58M Cyg 10.2 25 0
2022-Feb-26 22 15 +45 36 1.202 1.462 54M Lac 10.1 20 0
2022-Mar-03 22 49 +43 16 1.158 1.504 50M Lac 10.0 16 0
2022-Mar-08 23 18 +40 38 1.118 1.555 45E And 9.9 14 0
2022-Mar-13 23 43 +37 52 1.082 1.612 41E And 9.9 13 0
2022-Mar-18 00 04 +35 03 1.052 1.672 36E And 9.8 10 0
2022-Mar-23 00 23 +32 16 1.028 1.733 31E And 9.8 7 0
2022-Mar-28 00 39 +29 32 1.010 1.792 26E And 9.8 4 0
2022-Apr-02 00 54 +26 52 0.999 1.849 22E Psc 9.8 0 0
Comet Magnitude Formula
m1 = 8.5 + 5 log d + 10.0 log r (assumed)
C/2021 F1 (Lemmon-PANSTARRS) was discovered independently by the Catalina Sky Survey with their Mount Lemmon 1.5-m and Pan-STARRS with their Pan-STARRS1 1.8-m on Haleakala on 2021 March 19. At the time, the comet was asteroidal and 20-21st magnitude. Due to the lack of any detected cometary activity, the object was designated as A/2021 F1. Further follow-up observations taken between discovery and August 2021 all reported the object as inactive. A quick analysis of photometry submitted to the Minor Planet Center during that period is consistent with an inactive object with an absolute magnitude of 14.6 corresponding to a diameter of 8 km assuming an albedo of 0.04. It is a dynamically old long-period comet with an original 1/a value of +0.004927 au-1. This means it had (before its orbit was affected by the gravity of the major planets) a semi-major axis of ~203 au and orbital period of ~2800 years.
After reappearing after solar conjunction in December, a number of imagers reported cometary activity and was also 1-2 magnitudes brighter than its inactive absolute magnitude. Since then, the comet has rapidly increased in brightness with the most recent observation by J. J. Gonzalez on February 19 finding the comet at magnitude 10.3. This brightness is confirmed by a CCD brightness of 10.4 reported by Steffen Fritsche to the COBS site. The three observations submitted to the ALPO show the comet to be 4-5’ in diameter and very diffuse.
C/2021 F1 is headed towards a perihelion on 2022 April 6 at 1.00 au. Unfortunately, it is located on the far side of the Sun resulting in an apparently fainter object far from Earth and at small solar elongation. Too bad its wasn’t occurring around October 18. If that was the case, the comet would be passing 0.084 au from Earth and at magnitude 3.4 or brighter.
The comet is solely a northern object in February and March and not visible from the southern hemisphere. For our brightness predictions we assume the Gonzalez and Fritsche measurements are correct and the comet brightens at a rate of 10 log r (where r is the Sun-comet distance). If its rate of brightening is faster perhaps its will be a few tenths of a magnitude brighter than our predicted observed peak of magnitude 9.8. We say observed because C/2021 F1’s solar elongation will steadily fall from around ~60 deg in mid-February to less than 25 deg at the end of March as it moves through Lyra (Feb 1-2), Draco (Feb 2-3), Cygnus (Feb 3-24) Lacerta (Feb 24-March 4), Andromeda (March 4-March 31) and Pisces (March 31). As a result, it will be too close to the Sun for observation by the end of March even for Northern observers. Lemmon-PANSTARRS should reappear by mid-May, though only for southern observers and possible around 11th magnitude.
Comets Between Magnitude 10 and 13
4P/Faye
Discovered visually on 1843 November 23 by the Herve Faye
Orbit (from MPEC 2022-C234)
4P/Faye
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2021 Sept. 8.84473 TT Rudenko
q 1.6189103 (2000.0) P Q
n 0.13180037 Peri. 207.00527 +0.76775518 -0.63998446
a 3.8240624 Node 192.93052 +0.61016172 +0.74509744
e 0.5766517 Incl. 8.00832 +0.19558798 +0.18774902
P 7.48
From 6438 observations 1998 May 24-2022 Feb. 12, mean residual 0".9.
Nongravitational parameters A1 = +0.54, A2 = -0.0289.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
4P/Faye Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 06 24 +12 03 2.267 1.568 123E Gem 12.3 62 38
2022-Feb-26 06 27 +12 29 2.298 1.646 119E Gem 12.5 62 37
2022-Mar-03 06 31 +12 54 2.328 1.727 115E Gem 12.7 63 37
2022-Mar-08 06 35 +13 16 2.359 1.810 111E Gem 12.8 63 36
2022-Mar-13 06 39 +13 36 2.390 1.896 107E Gem 13.0 63 36
2022-Mar-18 06 44 +13 54 2.420 1.983 103E Gem 13.2 63 35
2022-Mar-23 06 49 +14 10 2.451 2.072 100E Gem 13.3 62 35
2022-Mar-28 06 55 +14 23 2.482 2.162 96E Gem 13.5 60 34
2022-Apr-02 07 01 +14 34 2.513 2.253 93E Gem 13.6 57 34
Comet Magnitude Formula (from fit to ALPO and COBS data)
m1 = 2.2 + 5 log d + 32.5 log r [through T -70 days]
m1 = 7.6 + 5 log d + 10.6 log r [since T -70 days]
where “t” is date of perihelion, “d” is Comet-Earth distance in au, and “r” is Comet-Sun distance in au
4P/Faye is slowly becoming a faint object for visual observers. Recent visual observations found a small (0.7-1.0’) coma. The comet should fade from around magnitude 12.0 in mid-February to 13.5 by the end of March as it moves through the evening constellations of Orion (Feb 1-20) and Gemini (Feb 20-Mar 31). Faye’s next perihelion will be in March 2029 though the comet will get no closer than 1.55 au to Earth. The return after that in September 2036 will be very similar to the current return with an approach to 0.97 au of Earth. We won’t see a better return till 2058 with a minimum Earth-comet distance of 0.74 au.
9P/Tempel
Discovered visually on 1867 April 3 by Ernst Wilhelm Leberecht Tempel of Marseille, France
Orbit (from MPEC 2022-C234)
9P/Tempel
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 Mar. 4.94891 TT Rudenko
q 1.5442324 (2000.0) P Q
n 0.17662663 Peri. 179.34907 -0.37340788 +0.91208337
a 3.1460474 Node 68.71410 -0.85193716 -0.26493204
e 0.5091516 Incl. 10.46999 -0.36710983 -0.31291362
P 5.58
From 1737 observations 2015 Nov. 11-2022 Feb. 9, mean residual 0".5.
Nongravitational parameters A1 = -0.16, A2 = -0.0838.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
9P/Tempel Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 18 15 -22 07 1.549 1.818 58M Sgr 12.3 15 33
2022-Feb-26 18 31 -22 26 1.546 1.787 59M Sgr 12.2 15 36
2022-Mar-03 18 47 -22 40 1.544 1.758 61M Sgr 12.2 14 38
2022-Mar-08 19 03 -22 50 1.544 1.730 62M Sgr 12.1 13 40
2022-Mar-13 19 19 -22 54 1.546 1.702 63M Sgr 12.1 13 42
2022-Mar-18 19 35 -22 55 1.550 1.676 65M Sgr 12.0 12 44
2022-Mar-23 19 50 -22 51 1.554 1.651 66M Sgr 12.0 11 46
2022-Mar-28 20 05 -22 44 1.561 1.626 68M Sgr 12.0 11 48
2022-Apr-02 20 20 -22 34 1.569 1.602 69M Cap 11.9 11 49
Comet Magnitude Formula (from Yoshida Seiichi’s page)
m1 = 7.5 + 5 log d + 18.0 log r(t-15)
where “t” is date of perihelion, “d” is Comet-Earth distance in au, and “r” is Comet-Sun distance in au
William Tempel of Marseilles, France discovered 12 comets visually between 1859 and 1877. 9P/Tempel was his 6th discovery and one of four periodic comets including 10P/Tempel, 11P/Tempel-Swift-LINEAR, and 55P/Tempel-Tuttle. Prior to the IAU’s change in comet naming and numbering in the 1990s, 9P was also known as Tempel 1. Note, that some organizations such as NASA and their Planetary Data System still use the old naming scheme so 9P is still cataloged by them as 9P/Tempel 1.
9P/Tempel best known as the target of two spacecraft missions. On 2005 July 4, NASA’s Deep Impact mission struck the comet’s nucleus with a 100 kg copper impactor. The mission wasn’t impacting the comet just for the sake of impacting or even as a hazard mitigation experiment (like the NASA DART mission launched last year to impact a moon of the small near-Earth asteroid Didymos). Impacting a comet results in ejecting material from below surface allowing the main non-impacting part of the Deep Impact mission to study fresher interior material. On 2011 February 15, NASA’s Stardust spacecraft (having previously flown by comet 81P/Wild) flew by 9P providing images of the post-Deep Impact crater. Due to the impact and released debris, Deep Impact itself was not able to directly image the post-impact surface before it flew past the comet. Thanks to the two missions, we now know 9P’s nucleus is rather large for a short-period comet with dimensions of 7.6 x 4.9 km (4.7 x 3.0 miles).
At discovery, 9P’s perihelion was at 1.53 au from the Sun. Close approaches to Jupiter in 1870 and 1881 increased Tempel’s perihelion distance out to 1.75 and 2.07 au, respectively. The larger perihelion distance resulted in 9P going undetected for ~88 years after its 1879 return. Though its perihelion dropped from 2.07 au in 1937 to 1.69 au in 1944 and 1.53 au in 1955, it was missed at what should have been a favorable 1961 return and not recovered till 1967. Though an unfavorable return was predicted for 1967, Dr. Elizabeth Roemer used the now named Kuiper 1.54-m reflector north of Tucson to photographically recover a faint 18th magnitude P/Tempel on a single night. Further observations during the next return in 1972 conformed the 1967 recovery. Since its 1955 return, Tempel’s perihelion has stayed around 1.5 au and its returns have alternated between very unfavorable and favorable. At its best return in 1994 it reached a maximum brightness of 9th magnitude.
Unfortunately, Tempel’s last good return was in 2005 (the same return as the Deep Impact collision) with a minimum Earth distance of 0.71 au. Close approaches to Jupiter in 2024 and 2036 will once again increase the perihelion distance to 1.77 and 1.93 au, respectively. This will result in the comet never getting closer than 0.95 au of Earth through the remainder of this century.
This February and March, 9P will be moving through the morning constellations of Ophiuchus (Feb 1-10), Sagittarius (Feb 10-Mar 28) and Capricornus (Mar 29-31). It should reach a peak brightness of around magnitude 12.0 in April.
22P/Kopff
Discovered photographically on 1906 August 23 by the August Kopff at the Königstuhl Observatory in Heidelberg, Germany
Orbit (from MPEC 2015-K139)
22P/Kopff
Epoch 2022 Mar. 2.0 TT = JDT 2459640.5
T 2022 Mar. 18.11295 TT MPCW
q 1.5524080 (2000.0) P Q
n 0.15445949 Peri. 163.02363 +0.24033534 +0.96809068
a 3.4402736 Node 120.83205 -0.89991689 +0.24962854
e 0.5487545 Incl. 4.74218 -0.36385232 +0.02204593
P 6.38
From 3050 observations 2001 Dec. 19-2015 May 26, mean residual 0".6.
Nongravitational parameters A1 = -0.06, A2 = -0.0620.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
22P/Kopff Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 19 33 -19 49 1.574 2.197 40M Sgr 11.1 6 17
2022-Feb-26 19 50 -19 18 1.566 2.169 41M Sgr 11.1 5 19
2022-Mar-03 20 06 -18 41 1.560 2.143 42M Cap 11.0 5 21
2022-Mar-08 20 22 -18 00 1.556 2.118 43M Cap 11.0 5 22
2022-Mar-13 20 38 -17 14 1.554 2.094 44M Cap 10.9 5 24
2022-Mar-18 20 53 -16 24 1.553 2.072 45M Cap 10.9 5 25
2022-Mar-23 21 08 -15 30 1.554 2.051 47M Cap 10.9 5 26
2022-Mar-28 21 23 -14 34 1.556 2.031 48M Cap 10.9 5 28
2022-Apr-02 21 38 -13 34 1.560 2.012 49M Cap 10.9 5 29
Comet Magnitude Formula (from Yoshida Seiichi’s page)
m1 = 5.3 + 5 log d + 21.0 log r
where “t” is date of perihelion, “d” is Comet-Earth distance in au, and “r” is Comet-Sun distance in au
August Kopff of the Königstuhl Observatory in Heidelberg, Germany discovered 22P/Kopff on 1906 August 23 on a photographic plate. 22P was one of two discoveries by Kopff. The other being long-period comet C/1906 E1 (Kopff). Though 22P was missed at its next return in 1912, it has been seen at ever return since with 2022 marking its 18th observed apparition.
22P/Kopff will be at perihelion on 2022 March 18 at 1.55 au. Closest approach to Earth won’t be till 2022 September 14 at 1.39 au though it will be a more distant 2.30 au from Sun at that time. This return is relatively poor with the comet brighter to around magnitude 11 at perihelion. It should still be around magnitude 11 in early April and slowly fade to around magnitude 12 by the end of June. The comet is observable from both hemispheres though difficult from the northern hemisphere in the morning sky as it moves through Sagittarius (Feb 1-March 3), Capricornus (March 3-28), Aquarius (March 28-29) and back into Capricornus (March 29-31). Too bad we aren’t observing from Mars as Kopff passed 0.19 au from Mars on February 14. Kopff, Mars and Venus spend most of March within a few degrees of each other (and even a visit by C/2021 E3, more below).
Imagers were able to observe Kopff during the first half of last year when it was still a distant object and faint at 17-18th magnitude. Since June of 2021, no observations of Kopff have been submitted to the ALPO, COBS, or MPC. This is mainly due to a small solar elongation though the comet has been further than 30 deg from the Sun since mid-January. Its solar elongation will continue to increase in February and March.
At discovery, perihelion was around 1.7 au and that remained the case till a close approach to Jupiter in 1943. Since then, perihelion has stayed in 1.48 to 1.59 au range. During that time the best returns occurred in 1983 and 1996 when Kopff reached 7th magnitude. Changes for the better are afoot. In 2026, another close approach to Jupiter will lower Kopff’s perihelion to 1.32 au. That and a close approach of 0.35 au to Earth in 2028 will make the comet’s next return its best. 2028 may see the comet brighten to 5-6th magnitude. After another gravitational nudge by Jupiter in 2038, Kopff’s perihelion will spend the rest of the 21st century around 1.16 au. Unfortunately, smaller perihelion won’t result in close approaches to Earth till late in the century (2084 at 0.43 au and 2095 at 0.20 au).
29P/Schwassmann-Wachmann
Discovered 1927 November 15 by the Arnold Schwassmann and Arno Arthur Wachmann at the Hamburg Observatory in Bergedorf, Germany
Centaur comet with orbital period of ~14.8 years
Orbit (from Minor Planet Center, MPEC 2022-C234)
29P/Schwassmann-Wachmann
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2019 Apr. 4.86535 TT Rudenko
q 5.7713426 (2000.0) P Q
n 0.06636462 Peri. 49.81575 +0.99174106 -0.04469966
a 6.0419665 Node 312.38181 -0.02057459 +0.86971628
e 0.0447907 Incl. 9.36627 +0.12659521 +0.49152368
P 14.9
From 12872 observations 2018 June 18-2022 Feb. 13, mean residual 0".5.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
29P/Schwassmann-Wachmann Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 04 18 +29 25 5.960 5.780 95E Tau 15.6 75 14
2022-Feb-26 04 19 +29 20 5.961 5.862 90E Tau 15.6 71 13
2022-Mar-03 04 21 +29 15 5.963 5.943 86E Tau 15.6 67 12
2022-Mar-08 04 23 +29 12 5.964 6.025 81E Tau 15.7 63 11
2022-Mar-13 04 25 +29 08 5.966 6.105 77E Tau 15.7 58 11
2022-Mar-18 04 27 +29 06 5.967 6.184 72E Tau 15.7 54 10
2022-Mar-23 04 30 +29 04 5.969 6.261 68E Tau 15.7 50 9
2022-Mar-28 04 33 +29 03 5.970 6.336 64E Tau 15.8 45 8
2022-Apr-02 04 36 +29 02 5.972 6.408 60E Tau 15.8 41 7
29P was especially active with multiple outbursts observed between September and November. Though the comet has settled down since last year, it did experience another outburst on February 11. Imaging photometry submitted to COBS through the start of February still found 29P to be around magnitude 10.0 to 10.5 and possess a large (~11-13’) coma suggesting the dust released in the late 2021 outbursts was still visible. By the end of February, the reported coma diameters were much smaller (>1’) and as a result the comet was once again observed to be fainter than 14th magnitude. Perhaps the 2021 dust coma has finally expanded to the point that it is no longer detectable.
29P is currently an evening object in Taurus and observable from both hemispheres though quickly getting low for southern observers. If you observe 29P, please consider contributing to two pro-am efforts to better understand this object: the British Astronomical Society’s (BAA) Mission 29P monitoring program coordinated by Richard Miles. ( https://britastro.org/node/18562 & https://britastro.org/node/25120 ) and the University of Maryland’s 29P Observation campaign (https://wirtanen.ast...P/29P_obs.shtml).
C/2019 T4 (ATLAS)
Discovered 2019 October 9 by the ATLAS survey
Dynamically old long-period comet
Orbit (from MPEC 2022-C56)
C/2019 T4 (ATLAS)
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 June 9.17106 TT Rudenko
q 4.2423795 (2000.0) P Q
z +0.0009758 Peri. 351.20606 -0.95991888 +0.05616222
+/-0.0000008 Node 199.94030 -0.18205844 -0.86982957
e 0.9958603 Incl. 53.62598 -0.21309734 +0.49014521
From 791 observations 2019 Feb. 5-2022 Feb. 12, mean residual 0".4.
1/a(orig) = +0.000622 AU**-1, 1/a(fut) = +0.000961 AU**-1.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
C/2019 T4 (ATLAS) Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 12 05 -27 58 4.337 3.601 133M Hya 12.0 22 78
2022-Feb-26 12 04 -27 24 4.328 3.544 137M Hya 11.9 23 77
2022-Mar-03 12 02 -26 45 4.320 3.493 142M Hya 11.9 23 77
2022-Mar-08 12 00 -26 01 4.313 3.448 146M Hya 12.0 24 76
2022-Mar-13 11 58 -25 12 4.305 3.410 150M Hya 12.0 25 75
2022-Mar-18 11 56 -24 18 4.299 3.379 154M Crv 11.9 26 74
2022-Mar-23 11 54 -23 20 4.292 3.356 157M Crt 11.9 27 73
2022-Mar-28 11 52 -22 19 4.286 3.340 158M Crt 11.9 28 72
2022-Apr-02 11 51 -21 14 4.280 3.332 159M Crt 11.9 29 71
Comet Magnitude Formula (from ALPO and COBS data)
m1 = 3.2 + 5 log d + 9.6 log r
C/2019 T4 (ATLAS) was discovered on 2019 October 6 at 19th magnitude with the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) 0.5-m reflector at Haleakala, Hawaii. At discovery, T4 ATLAS was 8.6 au from the Sun. Perihelion is in a few months on 2022 June 9 at a still distant 4.24 au. The comet is a dynamically old long-period comet last at perihelion ~64,000 years ago.
Chris Wyatt visually observed T4 on four occasions since the start of January finding the comet to be around magnitude 12.5-12.7 with moderately condensed ~1’ coma. The comet is brightening to around magnitude 12.0 in the morning sky in Hydra (Feb 1-Mar 13), Corvus (13-19), and Crater (19-31) and is visible from both hemispheres.
C/2021 A1 (Leonard)
Discovered 2021 January 3 by Greg Leonard of the Catalina Sky Survey with the 1.5-m on Mount Lemmon
Orbit (from Minor Planet Center MPEC 2022-C56)
C/2021 A1 (Leonard)
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 Jan. 3.29906 TT Rudenko
q 0.6152578 (2000.0) P Q
z -0.0000414 Peri. 225.09246 +0.63773960 +0.29161748
+/-0.0000008 Node 255.89590 +0.72791549 -0.53080564
e 1.0000255 Incl. 132.68654 -0.25184764 -0.79574155
From 2184 observations 2020 Apr. 11-2021 Dec. 23, mean residual 0".8.
1/a(orig) = +0.000519 AU**-1, 1/a(fut) = -0.000087 AU**-1.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
C/2021 A1 (Leonard) Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 21 26 -35 07 1.165 1.958 26M Mic 10.9 0 8
2022-Feb-26 21 24 -34 59 1.243 1.987 30M Mic 11.4 0 12
2022-Mar-03 21 22 -34 53 1.320 2.005 34M Mic 11.8 0 17
2022-Mar-08 21 20 -34 51 1.397 2.013 39M Mic 12.1 0 22
2022-Mar-13 21 17 -34 51 1.474 2.012 44M Mic 12.5 0 27
2022-Mar-18 21 14 -34 56 1.550 2.003 49M Mic 12.8 0 32
2022-Mar-23 21 11 -35 04 1.626 1.986 54M Mic 13.1 0 37
2022-Mar-28 21 06 -35 16 1.701 1.963 60M Mic 13.3 0 42
2022-Apr-02 21 02 -35 32 1.775 1.935 65M Mic 13.5 0 48
Comet Magnitude Formula & Lightcurve (from ALPO and COBS data)
m1 = 7.4 + 5 log d + 11.7 log r [to T-370 days, where T = date of perihelion]
m1 = 11.7 + 5 log d + 5.6 log r [T-370 to T-177 days]
m1 = 4.6 + 5 log d + 20.6 log r [T-177 to T-120 days]
m1 = 7.3 + 5 log d + 12.5 log r [T-120 to T-50 days]
m1 = 8.3 + 5 log d + 0.7 log r [T-50 to T-21 days]
m1 = 8.5 + 5 log d + 14.5 log r [T-21 and onwards]
where “t” is date of perihelion, “d” is Comet-Earth distance in au, and “r” is Comet-Sun distance in au
The Best Comet of 2021 may also turn out to be the Best Comet of 2022 thanks to being a faint naked eye object during the first week or so of January. Since then, C/2021 A1 (Leonard) rapidly faded to magnitude 8.5 by the end of January as it moves away from the Earth and Sun. Chris Wyatt was the last person to report seeing Leonard. On January 28 it was magnitude 8.5 with a 1.9’ coma and 9’ tail in a 0.25-m f/5 reflector at 40 power. With the comet too close to the Sun for observation since then, no other observations have been reported in February so far.
Observers in the southern hemisphere should pick the comet up again as we near the end of February as it moves away from the glow of dawn in Pisces Austrinus (Feb 1-16) and Microscopium (Feb 16-March 31). If Leonard is still fading at the same rate as observed in January it may only be magnitude 11 in late February and 13 by the end of March. Northern observers will have to wait till late April or early May to get another chance at observing Leonard though it may be a 14-15th magnitude object by then.
C/2021 E3 (ZTF)
Discovered 2021 March 9 by the Zwicky Transient Facility on Mount Palomar
Dynamically new long-period comet
Orbit (from MPEC 2022-A21)
C/2021 E3 (ZTF)
Epoch 2022 Jan. 21.0 TT = JDT 2459600.5
T 2022 June 11.90603 TT Rudenko
q 1.7774372 (2000.0) P Q
z -0.0004786 Peri. 228.84485 -0.11524750 -0.43255660
m+/-0.0000021 Node 104.46808 -0.37426706 +0.85277571
e 1.0008508 Incl. 112.55711 -0.92013161 -0.29269160
From 852 observations 2021 Mar. 9-Dec. 14, mean residual 0".4.
1/a(orig) = -0.000033 AU**-1, 1/a(fut) = +0.000618 AU**-1.
Ephemerides (produced with Seiichi Yoshida’s Comets for Windows program)
C/2021 E3 (ZTF) Max El
(deg)
Date R.A. Decl. r d Elong Const Mag 40N 40S
2022-Feb-21 20 05 -15 52 2.262 3.039 32M Sgr 13.4 3 9
2022-Feb-26 20 11 -16 51 2.225 2.950 35M Cap 13.2 4 13
2022-Mar-03 20 16 -17 54 2.189 2.856 39M Cap 13.1 4 18
2022-Mar-08 20 21 -19 01 2.154 2.757 43M Cap 12.9 4 23
2022-Mar-13 20 27 -20 15 2.120 2.654 47M Cap 12.8 5 28
2022-Mar-18 20 32 -21 35 2.087 2.547 51M Cap 12.6 5 32
2022-Mar-23 20 38 -23 05 2.055 2.437 56M Cap 12.5 4 37
2022-Mar-28 20 44 -24 44 2.024 2.324 60M Cap 12.3 4 41
2022-Apr-02 20 50 -26 36 1.995 2.209 64M Cap 12.1 3 46
Comet Magnitude Formula (from ALPO and COBS data)
m1 = 7.4 + 5 log d + 10.0 log r
The Zwicky Transient Facility used the 1.2-m Oschin Schmidt to detect Comet ZTF as an asteroid on 2021 March 9 at 19th magnitude. Follow-up observations detected cometary activity resulting in its announcement as comet C/2021 E3 (ZTF). Perihelion occurs on 2022 June 11 at 1.78 au.
While no visual observations have been submitted to the ALPO or even COBS, digital photometry reported on the COBS site had the comet around 14-15th magnitude in late November. Since then, the comet has been located at small solar elongation and a difficult, if not impossible, object to observe. Though still difficult from the northern hemisphere, it should become a progressively easier object to observe from the southern hemisphere in March. ZTF should be a 12-13th magnitude object for the remainder of February and March as it moves through Sagittarius (Feb 1 – 22) and Capricornus (Feb 22 – Mar 31).
C/2021 E3 may get as bright as 10th magnitude in June when it will be at perihelion (1.78 au) and minimum distance to Earth (1.21 au). At that time, it will be located deep in the southern sky (passing within 10 degrees of the South Celestial Pole). It will be invisible from the northern hemisphere from April till late in the year when it should be too faint to be a visual object.
New Discoveries, Recoveries and Other Comets News
New Comet Numberings (Ref: WGSBN Bull. 2 #2)
440P/1997 B1 = 2021 W2 (Kobayashi)
439P/2008 WZ96 = 2021 W1 (LINEAR)
438P/2005 T2 = 2012 V5 = 2020 OV62 (Christensen)
437P/2021 V3 = 2011 UE215 (PANSTARRS)
New Comet Discoveries
P/2022 C3 (PANSTARRS) - The Pan-STARRS2 1.8-m Ritchey-Chretien reflector on Haleakala, Hawaii found this new short-period comet on February 9 at 20th magnitude. This short-period comet has an orbital period of 29.6 years and a perihelion of 4.37 au on 2022 July 2. It should peak around magnitude 19 at opposition in May. [Ref: CBET 5099, MPEC 2022-D02]
P/2022 C2 (PANSTARRS) – Yet another 20th magnitude short-period comet was found by the Pan-STARRS2 1.8-m Ritchey-Chretien reflector on Haleakala, Hawaii, this time on February 2. It has an orbital period of 15.3 years and a perihelion of 3.40 au on 2022 July 28. It should peak around magnitude 19 at opposition in April. [Ref: 5098, MPEC 2022-D01]
P/2022 C1 (PANSTARRS) – Let’s do this one more time... The Pan-STARRS2 1.8-m Ritchey-Chretien reflector on Haleakala, Hawaii found a new short-period comet on February 3 at 20th magnitude. Pre-discovery observations back to 2021 November 6 by Pan-STARRS and the Mount Lemmon Survey were also identified. Perihelion was on 2021 November 4 at 3.99 au. Since we are already past perihelion, P/2022 C1 now fading. [Ref: CBET 5096, MPEC 2022-C74]
2022 BG4 – This asteroid is on a high-eccentricity orbit that takes it from a perihelion at 1.11 au out to near the orbit of Uranus at 18.5 au. Pan-STARRS first saw this object on 2022 January 20 at 21st magnitude. It will pass no closer than 1.19 au from Earth and has already peaked in brightness. With an absolute magnitude of 18.6 and assumed albedo of 0.04, it has a diameter of ~1.3 km.
A/2022 B3 – The Catalina Sky Survey discovered this apparently asteroidal object on a long-period comet orbit on 2022 January 31 at 21st magnitude with the University of Arizona’s Bok 2.3-m telescope on Kitt Peak. Perihelion was on 2022 January 17 at 3.70 au. Unless the object becomes active, it has likely reached its maximum brightness. [Ref: MPEC 2022-D24]
P/2022 B2 = P/2017 R1 (PANSTARRS) – Michael Rudenko of the Minor Planet Center identified this returning comet in images taken in January and February of 2022 by Pan-STARRS and Kacper Wierzchos with the Mount Lemmon 1.5-m. The comet was discovered on 2017 September 14 and reached a peak of 20th magnitude. It isn’t due back at perihelion till 2025 September 9 at 3.33 au almost 2.5 years from now. Its early recovery suggests either a large nucleus or the comet has experienced a recent outburst. [Ref: CBET 5100, MPEC 2022-D03]
In addition to working on comets at the Minor Planet Center, Rudenko’s name is also familiar to comet observers as the visual discoverer of 3 comets in the 1980s: C/1984 V1 (Levy-Rudenko), C/1987 Q1 (Rudenko), and C/1989 Q1 (Okazaki-Levy-Rudenko).
P/2022 B1 (Wierzchos) – Kacper Wierzchos found a new 19th magnitude short-period comet on January 25 with the Mount Lemmon 1.5-m reflector. Pre-discovery observations were found back to 2020 October 30. Perihelion takes place on 2022 February 25 at 1.90 au. Though still moving towards the Sun, the comet is moving away from Earth and is already fading. With a 12.8-year period, the comet will return to perihelion on 2034 December 21. P/2022 B1 is the 4th comet discovery by Wierzchos to bear his name with all discovered since 2020. [Ref: CBET 5094, MPEC 2022-C02]
C/2022 A2 (PANSTARRS) – On January 9, the Pan-STARRS survey discovered a C/2022 A2 (PANSTARRS) at 19-20th magnitude with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector on Haleakala, Hawaii. At discovery, the comet was 4.88 au from the Sun and 4.63 au from Earth. At perihelion on 2023 February 12, the comet will be much closer to the Sun at 1.74 au. Unfortunately, it will still be far from Earth at 1.88 au. Unless it brightens rapidly, it may only reach 13th magnitude at perihelion. Still, this will be one to watch as it could end up in the range of visual observers. [Ref: CBET 5093, MPEC 2022-C01]
C/2022 A1 (Sárneczky) - Krisztian Sárneczky discovered a nearby comet on January 2 with Konkoly Observatory’s Piszkesteto Station 0.60-m Schmidt telescope. Sárneczky is the first Hungarian astronomer to discover a comet since Miklós Lovas found 184P/Lovas in 1986. C/2022 A1 is a dynamically old long-period comet with a current orbital period of ~18,000 years. It reached a peak brightness of 16-17th magnitude when it passed 0.32 au from Earth on January 8. Now moving away from the Earth and past its January 31 perihelion at 1.25 au, the comet is rapidly fading from ~19th magnitude to 21st over the course of February. [ref: CBET 5090, MPEC 2022-A59]
C/2021 Y1 (ATLAS) – The "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) survey used their 0.5-m f/2 Schmidt reflector on Mauna Loa in Hawaii to find this 18th magnitude comet on 2021 December 26. A relatively distant find at 5.5 au from the Sun, C/2021 Y1 may reach 12-13th magnitude when it arrives at perihelion on 2023 April 30 at 2.03 au. [Ref: CBET 5089, MPEC 2022-A50]
440P/2021 W2 = P/1997 B1 (Kobayashi) – Observers using a 1.04-m f/1.8 Schmidt telescope at the XuYi Station of the Purple Mountain Observatory reported the discovery on January 11 of a possible near-Earth asteroid. Further observations were identified by the Pan-STARRS survey and the University of Arizona’s 2.25-m Bok reflector on Kitt Peak going back to 2021 November 9. The object was reported as cometary in some of the Pan-STARRS observations. The Minor Planet Center identified the “new” object as a recovery of P/1997 B1 (Kobayashi).
Comet Kobayashi was discovered by Takao Kobayashi at Oizumi, Japan on 1997 January 30 with a 0.41-m f/4.3 reflector. During the 1997 apparition, the comet reached a peak brightness of 16-17th magnitude. With a 25-year orbital period, 2022 marks the comet’s first return since discovery with perihelion on March 29 at 2.06 au. If the comet is as active as in 1997, it will peak around 17th magnitude, though currently the comet is running about 2 magnitudes fainter than expected. The comet has been officially numbered as 440P/Kobayashi. [Ref: CBET 5092, MPEC 2022-A164]
P/2020 B4 (Sheppard) – Scott Sheppard of the Carnegie Institution for Science in Washington, D.C. was using the Cerro Tololo 4-m Blanco telescope on 2020 January 26 and 27 when he found a faint 22nd magnitude comet on single images taken on each night. Following requests from the Minor Planet Center to search archival images, Sam Deen found an image of the comet from 2020 February 11 taken with the same telescope. Robert Weryk of the University of Western Ontario was also able to find the comet on multiple nights of Pan-STARRS observations (2019 Nov. 5, 25, 29; 2020 Feb. 4, May 12, and a targeted observation on 2021 Feb. 7). [Ref: CBET 5102]
As always, the Comet Section is happy to receive all comet observations, whether textual descriptions, images, drawings, magnitude estimates, or spectra. Please send your observations via email to the Comets Section < comets @ alpo-astronomy .org >, Comets Section Coordinator Carl Hergenrother < carl.hergenrother @ alpo-astronomy .org > and/or Comets Section Acting Assistant Coordinator Michel Deconinck < michel.deconinck @ alpo-astronomy .org >.
Thank you to everyone who contributed to the ALPO Comets Section!
Clear skies!
- Carl Hergenrother
