Electronic Telegram No. 5437 Central Bureau for Astronomical Telegrams Mailing address: Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network COMET P/2024 Q1 (PANSTARRS) R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reports the discovery of another comet in images obtained on Aug. 27 with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala; the discovery observations are tabulated below, along with the last two that were made on the same night with the Pan-STARRS2 1.8-m reflector at Haleakala. The four stacked 45-s w-band survey discovery images, taken in 1".4-1".9 seeing, show a condensed head of size 2".3 (full-width-at-half-maximum) with an 8" tail toward p.a. 225 deg. 2024 UT R.A. (2000) Decl. Mag. Aug. 27.54271 0 28 25.58 - 3 33 08.2 20.2 27.55322 0 28 25.27 - 3 33 07.6 20.6 27.56372 0 28 24.98 - 3 33 07.0 20.3 27.57425 0 28 24.67 - 3 33 06.1 20.5 27.62966 0 28 23.09 - 3 33 02.7 19.7 27.63032 0 28 23.08 - 3 33 02.5 20.0 Weryk adds that he also identified pre-discovery images of the comet in Pan-STARRS1 images obtained on July 30.54-30.58 UT (mag 20.2-20.5) and in Pan-STARRS2 images obtained on Aug. 12.6 (mag 20.5-20.9). The image quality on July 30 was "not great", but the object is clearly cometary on Aug. 12, where four stacked 45-s w-band survey images taken in 1".2-1".8 seeing show a condensed head of size 2".3 (FWHM) and an 8" tail toward p.a. 225 deg. Three 60-s gri-band follow-up images obtained on Aug. 29.49 with the 3.6-m Canada- France-Hawaii Telescope at Mauna Kea by Weryk and R. Wainscoat (queue observer A. Acohido; queue coordinator H. Flewelling) in 0".7 seeing show a very condensed head of size 1".0 (FWHM) with a broad 8" tail spanning p.a. 235-250 degrees. After the comet was posted to the Minor Planet Center's PCCP webpage, S. Deen (Simi Valley, CA, USA) identified a single image of the comet on an image obtained on June 3.39 UT with the 4-m Cerro Tololo reflector (+ DECam); the comet appeared slightly condensed with an elongated shape of size 1".2 x 1".8 (FWHM) in 1".2 seeing, with a magnitude of r = 20.8 and an 8" tail toward p.a. 245 degrees. One-hundred-forty stacked 30-s CMO exposures taken on Aug. 28.1 by L. Buzzi at Varese, Italy, with a 0.84-m f/3.5 reflector (measured by A. Aletti and Buzzi) show a moderately condensed 8" coma with a faint tail extended for approximately 10" in p.a. 235 degrees. The available astrometry appears on MPEC 2024-Q87. The following orbital elements by S. Nakano (Central Bureau) are from 52 observations spanning 2024 June 3-Aug. 30 (mean residual 0".6). The comet passed 0.32 AU from Jupiter on 2015 Mar. 17 UT. Note the slightly uncomfortable emphasis on the sole observation on June 3 (nearly two months earlier than the rest). Epoch = 2004 Feb. 5.0 TT T = 2004 Jan. 16.34251 TT Peri. = 215.88864 e = 0.5048246 Node = 92.13036 2000.0 q = 1.8115008 AU Incl. = 5.88693 a = 3.6583012 AU n = 0.14085909 P = 7.00 years Epoch = 2010 Dec. 30.0 TT T = 2011 Jan. 14.19501 TT Peri. = 216.06860 e = 0.5056439 Node = 92.06051 2000.0 q = 1.8047090 AU Incl. = 5.88653 a = 3.6506259 AU n = 0.14130355 P = 6.98 years Epoch = 2017 Nov. 23.0 TT T = 2017 Nov. 8.88811 TT Peri. = 284.22575 e = 0.5346631 Node = 23.23434 2000.0 q = 1.6350016 AU Incl. = 5.01623 a = 3.5135871 AU n = 0.14965044 P = 6.59 years Epoch = 2024 June 19.0 TT T = 2024 June 14.54096 TT Peri. = 284.41976 e = 0.5344080 Node = 23.13034 2000.0 q = 1.6362405 AU Incl. = 5.01538 a = 3.5143228 AU n = 0.14960345 P = 6.59 years Epoch = 2031 Feb. 23.0 TT T = 2031 Feb. 4.82651 TT Peri. = 285.40203 e = 0.5267379 Node = 22.33746 2000.0 q = 1.6784133 AU Incl. = 4.98986 a = 3.5464769 AU n = 0.14757350 P = 6.68 years Epoch = 2037 Oct. 29.0 TT T = 2037 Oct. 16.64779 TT Peri. = 285.62945 e = 0.5257981 Node = 22.18944 2000.0 q = 1.6855911 AU Incl. = 4.98659 a = 3.5545849 AU n = 0.14706886 P = 6.70 years Epoch = 2044 July 4.0 TT T = 2044 June 24.19528 TT Peri. = 285.52790 e = 0.5264532 Node = 22.16035 2000.0 q = 1.6822630 AU Incl. = 4.98744 a = 3.5524745 AU n = 0.14719994 P = 6.70 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 17.0 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2024 07 29 00 23.89 -05 11.3 0.916 1.693 122.3 30.4 19.1 2024 08 08 00 29.36 -04 21.7 0.881 1.720 130.3 26.7 19.1 2024 08 18 00 30.74 -03 49.6 0.856 1.752 139.2 22.2 19.1 2024 08 28 00 28.24 -03 32.6 0.844 1.788 149.2 16.8 19.2 2024 09 07 00 22.48 -03 26.7 0.848 1.828 160.0 10.9 19.3 2024 09 17 00 14.77 -03 25.4 0.872 1.871 171.0 4.8 19.4 2024 09 27 00 06.69 -03 22.1 0.917 1.917 174.6 2.8 19.6 2024 10 07 23 59.73 -03 11.5 0.984 1.965 164.5 7.8 19.9 2024 10 17 23 55.01 -02 49.9 1.073 2.016 153.9 12.6 20.2 2024 10 27 23 53.06 -02 16.4 1.182 2.068 143.8 16.5 20.5 2024 11 06 23 53.94 -01 31.2 1.308 2.122 134.3 19.5 20.9 2024 11 16 23 57.46 -00 35.5 1.450 2.177 125.4 21.7 21.2 2024 11 26 00 03.24 +00 29.0 1.604 2.233 117.1 23.2 21.5 2024 12 06 00 10.91 +01 40.9 1.769 2.290 109.2 24.0 21.8 2024 12 16 00 20.13 +02 58.6 1.942 2.347 101.6 24.2 22.1 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2024 CBAT 2024 August 31 (CBET 5437) Daniel W. E. Green