[Iaude] CBET 5302: COMET P/2023 T1
quai at eps.harvard.edu
quai at eps.harvard.edu
Wed Oct 18 00:31:09 EDT 2023
Electronic Telegram No. 5302
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 T1 (PANSTARRS)
R. Weryk, Department of Physics and Astronomy, University of Western
Ontario, reports the discovery of another comet in images obtained with the
Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala, Hawaii (discovery
observations tabulated below). Four 45-s w-band survey images taken in 1".2
seeing showed a very condensed head of size 1".9 (full-width-at-half-maximum).
2023 UT R.A. (2000) Decl. Mag.
Oct. 9.45275 3 17 11.32 +22 38 04.7 20.4
9.46493 3 17 11.08 +22 38 03.6 21.0
9.47714 3 17 10.85 +22 38 02.3 20.8
9.48956 3 17 10.61 +22 38 00.9 20.8
Weryk adds that four 45-s w-band survey images taken on Oct. 15.4 UT with the
Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala in 0".8 seeing
show a very condensed head of size 1".3 (FWHM) and a straight tail about 3"
long in p.a 250 degrees. Weryk also relates that four 60-s gri-band
follow-up images taken on Oct. 13.5 with the 3.6-m Canada-France-Hawaii
Telescope (queue observer L. Wells; queue coordinator T. Burdullis) shows
that this object is clearly a comet, with the best image in 0".5 seeing
showing a condensed head of size 1".1 (FWHM) with a 2" tail in p.a. 260 deg.
Weryk also identified pre-discovery observations taken on July 16.6 with
the Pan-STARRS2 telescope (at mag 21.9-22.2).
After the object was posted on the Minor Planet Center's PCCP webpage,
other CCD astrometrists have commented on the cometary appearance. L. Buzzi
(Varese, Italy) writes that two-hundred-thirty-eight stacked 30-s exposures
taken on Oct. 11.1 UT by G. Galli and himself (and measured by A. Aletti,
Buzzi, and Galli) with a 0.84-m f/3.5 reflector show a very condensed coma
6" wide (with a FWHM slightly larger than nearby stars stars. Ten stacked
120-s exposures taken remotely on Oct. 11.4 UT by H. Sato (Bunkyo-ku, Tokyo,
Japan) with a 0.51-m f/6.8 astrograph located at the Utah Desert Remote
Observatory (near Beryl Junction, UT, USA) show a moderately condensed coma
8" in diameter with no tail; the magnitude was 20.3 as measured within a
circular aperture of radius 4".9.
MPEC 2023-U53 contains the available astrometry, including pre-discovery
observations reported subsequently that were obtained at Mt. Lemmon on Sept.
15.4 (mag 20.6-20.9) and 25.4 UT. The following orbital elements by S. Nakano
(Central Bureau) are from 50 observations spanning 2023 July 16-Oct. 17 (mean
residual 0".4). Nakano notes that the orbit is still uncertain and notes the
potential problem of single-night observations in July. These elements
indicate that the comet passed 0.054 AU and 0.15 AU from Jupiter on 2007 Oct.
29 and on 2019 May 16 UT, respectively. The previous orbit in 1978 would
then have elements T = 1978 Sept. 30, q = 5.05 AU, e = 0.46, Peri. = 166.1
deg, Node = 87.6 deg, i = 2.5 deg, a = 9.34 AU, P = 28.5 years. Nakano was
unable to identify earlier archival observations.
Epoch = 1978 Oct. 19.0 TT
T = 1978 Sept.30.28213 TT Peri. = 166.12231
e = 0.4590374 Node = 87.63111 2000.0
q = 5.0505353 AU Incl. = 2.51372
a = 9.3362000 AU n = 0.03455006 P = 28.53 years
Epoch = 2007 May 20.0 TT
T = 2007 May 20.61362 TT Peri. = 163.41720
e = 0.5470686 Node = 86.24416 2000.0
q = 5.1038023 AU Incl. = 2.53706
a = 11.2683784 AU n = 0.02605625 P = 37.83 years
Epoch = 2016 Oct. 19.0 TT
T = 2016 Sept.30.30147 TT Peri. = 251.45889
e = 0.2305156 Node = 262.02436 2000.0
q = 4.0121178 AU Incl. = 4.02854
a = 5.2140343 AU n = 0.08278340 P = 11.91 years
Epoch = 2024 May 10.0 TT
T = 2024 May 22.90744 TT Peri. = 202.86534
e = 0.3339717 Node = 249.57539 2000.0
q = 2.8172477 AU Incl. = 6.61194
a = 4.2299215 AU n = 0.11329366 P = 8.70 years
Epoch = 2033 Feb. 12.0 TT
T = 2033 Jan. 31.75255 TT Peri. = 202.71973
e = 0.3323456 Node = 249.57254 2000.0
q = 2.8305667 AU Incl. = 6.60339
a = 4.2395685 AU n = 0.11290719 P = 8.73 years
The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 13.0 and 2.5n = 10 for the
magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2023 09 13 03 17.64 +22 48.6 2.589 3.169 116.5 16.5 20.1
2023 09 23 03 19.24 +22 53.1 2.450 3.145 125.9 15.0 19.9
2023 10 03 03 18.69 +22 47.5 2.325 3.121 135.8 12.9 19.8
2023 10 13 03 15.99 +22 30.9 2.218 3.098 146.3 10.3 19.6
2023 10 23 03 11.34 +22 03.1 2.133 3.075 157.2 7.2 19.5
2023 11 02 03 05.23 +21 24.8 2.075 3.053 168.5 3.7 19.4
2023 11 12 02 58.33 +20 38.3 2.044 3.032 176.3 1.2 19.4
2023 11 22 02 51.51 +19 47.2 2.042 3.012 166.8 4.3 19.3
2023 12 02 02 45.63 +18 56.6 2.068 2.992 155.4 7.9 19.3
2023 12 12 02 41.36 +18 11.0 2.119 2.974 144.1 11.2 19.4
2023 12 22 02 39.21 +17 34.6 2.193 2.956 133.3 14.0 19.4
2024 01 01 02 39.38 +17 09.6 2.285 2.939 123.1 16.3 19.5
2024 01 11 02 41.88 +16 56.8 2.390 2.923 113.4 18.0 19.6
2024 01 21 02 46.64 +16 55.8 2.505 2.908 104.3 19.1 19.6
2024 01 31 02 53.45 +17 05.1 2.625 2.895 95.7 19.8 19.7
2024 02 10 03 02.10 +17 23.1 2.748 2.882 87.6 20.0 19.8
2024 02 20 03 12.39 +17 47.6 2.871 2.870 80.0 19.8 19.9
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2023 CBAT
2023 October 18 (CBET 5302) Daniel W. E. Green
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