[Iaude] CBET 5341: COMET P/2023 X5 = P/2017 O4
quai at eps.harvard.edu
quai at eps.harvard.edu
Sun Jan 28 23:31:11 EST 2024
Electronic Telegram No. 5341
Central Bureau for Astronomical Telegrams
Mailing address: Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network
COMET P/2023 X5 = P/2017 O4 (HOGAN)
Joshua K. Hogan, Lunar and Planetary Laboratory (LPL), University of
Arizona, reports his discovery of a comet with a "long tail" on 30-s CCD
exposures taken with the Mt. Lemmon Survey's 1.5-m reflector in Arizona on
2023 Dec. 15 UT (discovery observations tabulated below).
2023 UT R.A. (2000) Decl. Mag. Observer
Dec. 15.25302 4 51 18.60 +23 51 38.0 20.0 Hogan
15.25819 4 51 18.32 +23 51 37.6 20.4 "
15.26339 4 51 17.99 +23 51 36.9 20.1 "
15.26856 4 51 17.74 +23 51 36.9 20.3 "
Additional astrometry appears on MPEC 2024-B74, where the comet was
mistakenly designated "P/2023 S4", inadvertently attributing a pre-discovery
Mt. Lemmon observation from 2023 Sept. 25 (found in the Minor Planet Center's
"isolated tracklet file") as the discovery observation. Apparently asteroidal
observations of the comet were later found in the MPC's ITF from images
obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala
on 2023 Nov. 8 (at mag 21.1-21.7).
After the object was posted on the MPC's PCCP webpage, R. Weryk
(Department of Physics and Astronomy, University of Western Ontario)
identified images of the comet taken with the Pan-STARRS1 telescope on 2023
Dec. 4.33-4.37 UT, when four 45-s w-band survey images taken in 1".1 seeing
then showed a very condensed coma of size 1".2 with a tail at least 30" long
in p.a. 260 degrees. Weryk identified additional observations with the
Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala that were obtained
on 2023 Aug. 18.6 (mag 21.6-22.6), Aug. 24.6 (mag 21.6-22.3), and Oct. 22.5
(mag 21.6-21.7), as well as additional Pan-STARRS1 observations on 2023 Dec.
15.5 (mag 20.6-20.8). Weryk then found even earlier Pan-STARRS1 from 2017
July 30 (mag 23.4), 2017 Sept. 17 (mag 22.6-23.1) and 24 (mag 22.0-22.4), 2017
Oct. 11 (mag 21.7-22.5), Oct. 18 (mag 21.8-22.5), Oct. 23 (mag 22.0-22.2),
2017 Nov. 19 (mag 22.6), and 2019 Jan. 5 (mag 24.1) and 14 (mag 23.0-23.5) --
adding that it does not look cometary in those older data. Selected
pertinent Pan-STARRS1 astrometry is tabulated below:
2017 UT R.A. (2000) Decl. Mag.
July 30.58221 1 13 30.56 + 7 05 03.1 23.4
30.59155 1 13 30.87 + 7 05 05.1 23.4
30.60089 1 13 31.19 + 7 05 07.8
2019 UT R.A. (2000) Decl. Mag.
Jan. 14.59256 9 04 49.12 +18 21 08.5 23.1
14.60617 9 04 48.47 +18 21 11.1 23.5
14.61980 9 04 47.86 +18 21 13.8 23.0
After the comet was posted on the MPC's PCCP webpage, H. Sato (Bunkyo-ku,
Tokyo, Japan) reported that twelve stacked 60-s CCD exposures taken remotely
with a "Deep Sky Chile" 0.51-m f/6.8 astrograph located at Rio Hurtado, Chile,
on 2023 Dec. 19.1 UT show a moderately condensed coma 5" in diameter with a
hint of tail 5" long toward p.a. 290 degrees; the magnitude was 20.4 as
measured within a circular aperture of radius 2".8.
S. Deen (Simi Valley, CA, USA) found apparent images of the comet on
four nights in publicly available data, from observations obtained with the
3.6-m Canada-France-Hawaii Telescope by B. Gladman on 2005 June 14 and 15
(mag r = 23.6-23.8) and on 2017 July 17 and 23 (mag V = 23.7-24.0). Deen
saw no cometary activity in any of these images. The 2005 June 14-15 images
were all 110-s R-band exposures. Deen also found what appear to be stellar
trailed images of the comet at a time when the comet was close to aphelion on
two 420-s VR-band DECam exposures taken on 2021 June 13.0 and 13.2 UT by S.
Sheppard in the course of his transneptunian-object survey with the 4-m
reflector at Cerro Tololo, the magnitude measured by Deen to be 24.2-24.3.
2005 UT R.A. (2000) Decl. Mag. Observer
June 14.46100 19 34 48.62 -23 09 50.8 23.6 Gladman
14.48545 19 34 47.71 -23 09 53.3 "
15.45739 19 34 13.17 -23 11 29.7 23.8 "
2017 UT R.A. (2000) Decl. Mag. Observer
July 17.61600 1 04 44.19 + 6 10 23.7 24.0 Gladman
23.62323 1 09 09.25 + 6 37 56.4 23.7 "
2021 UT R.A. (2000) Decl. Mag. Observer
June 13.02828 16 12 01.82 -22 10 28.3 24.3 Sheppard
13.15893 16 11 55.77 -22 10 14.0 24.2 "
The following linked orbital elements by S. Nakano (Central Bureau) are
from 120 observations spanning 2005 June 14-2024 Jan. 17 (mean residual 0".4).
While there are no close approach to major planets, the comet passed 0.08 AU
from (1) Ceres on 2012 Dec. 22 UT.
Epoch = 2006 Dec. 11.0 TT
T = 2006 Dec. 12.00569 TT Peri. = 13.46881
e = 0.1861814 Node = 26.92659 2000.0
q = 2.5509408 AU Incl. = 1.10270
a = 3.1345326 AU n = 0.17760078 P = 5.55 years
Epoch = 2012 July 12.0 TT
T = 2012 June 26.48646 TT Peri. = 13.18023
e = 0.1885194 Node = 26.90806 2000.0
q = 2.5433515 AU Incl. = 1.10151
a = 3.1342109 AU n = 0.17762813 P = 5.55 years
Epoch = 2018 Jan. 2.0 TT
T = 2018 Jan. 5.50886 TT Peri. = 12.41625
e = 0.1882315 Node = 26.77566 2000.0
q = 2.5426081 AU Incl. = 1.09967
a = 3.1321835 AU n = 0.17780062 P = 5.54 years
Epoch = 2023 Aug. 4.0 TT
T = 2023 July 16.76712 TT Peri. = 11.45139
e = 0.1890793 Node = 26.79277 2000.0
q = 2.5416089 AU Incl. = 1.09786
a = 3.1342264 AU n = 0.17762681 P = 5.55 years
Epoch = 2029 Jan. 24.0 TT
T = 2029 Jan. 27.84350 TT Peri. = 11.06146
e = 0.1872100 Node = 26.75623 2000.0
q = 2.5467909 AU Incl. = 1.09638
a = 3.1333936 AU n = 0.17769763 P = 5.55 years
Epoch = 2034 Aug. 26.0 TT
T = 2034 Aug. 10.29561 TT Peri. = 9.94415
e = 0.1843328 Node = 26.73850 2000.0
q = 2.5583315 AU Incl. = 1.09457
a = 3.1364894 AU n = 0.17743461 P = 5.56 years
The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 14.5 and 2.5n = 10 for the
magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2024 01 11 04 34.25 +23 20.0 1.837 2.670 140.5 13.6 20.1
2024 01 21 04 32.59 +23 14.5 1.944 2.683 129.9 16.3 20.2
2024 01 31 04 33.78 +23 14.4 2.067 2.698 120.0 18.4 20.4
2024 02 10 04 37.63 +23 19.2 2.201 2.712 110.8 19.9 20.5
2024 02 20 04 43.90 +23 28.2 2.343 2.727 102.1 20.8 20.7
2024 03 01 04 52.25 +23 39.7 2.490 2.743 94.0 21.1 20.9
2024 03 11 05 02.38 +23 52.2 2.639 2.759 86.3 21.1 21.0
2024 03 21 05 14.02 +24 04.1 2.788 2.775 79.0 20.6 21.2
2024 03 31 05 26.90 +24 14.0 2.933 2.792 72.0 19.9 21.3
2024 04 10 05 40.79 +24 20.7 3.075 2.809 65.3 18.9 21.4
2024 04 20 05 55.50 +24 23.1 3.211 2.826 58.9 17.7 21.5
2024 04 30 06 10.85 +24 20.4 3.339 2.844 52.7 16.4 21.7
2024 05 10 06 26.68 +24 12.0 3.460 2.861 46.6 14.9 21.8
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2024 CBAT
2024 January 29 (CBET 5341) Daniel W. E. Green
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