Electronic Telegram No. 5185 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 C/2022 S5 (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). 2022 UT R.A. (2000) Decl. Mag. Sept.24.50473 2 20 23.43 -17 54 35.5 19.5 24.51553 2 20 21.37 -17 55 12.5 19.5 24.52637 2 20 19.31 -17 55 49.8 19.7 24.53714 2 20 17.26 -17 56 26.7 19.9 24.59254 2 20 06.68 -17 59 36.6 19.4 24.59335 2 20 06.53 -17 59 39.4 19.2 Weryk and R. Wainscoat obtained three 60-s gri-band follow-up images with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea on Sept. 28.55 UT (queue observer H. Januszewski; queue coordinator N. Manset) in 0".8 seeing, which show a very condensed head of size 0".8 (full-width-at-half-maximum) and a broad, very short tail (possibly viewed end-on) that moves with the object, spanning p.a. 200-320 degrees. Three 60-s follow-up CFHT exposures taken on Oct. 29.3 (queue observer A. Acohido; queue coordinator E. Bertin) in poor seeing (1".6-1".8) show the comet's head to be similar to star images, but there seems to be a very-low-surface-brightness tail extending towards p.a. about 70 degrees for about 7". After the object was posted on the Minor Planet Center's PCCP webpage, H. Sato (Bunkyo-ku, Tokyo, Japan) reported that twenty-four stacked 15-s CCD exposures taken remotely with a 0.51-m f/6.8 astrograph at Rio Hurtado, Chile, on Oct. 1.14 show only a stellar appearance; the magnitude was 19.6 as measured within a circular aperture of radius 2".9. The available astrometry appears on MPEC 2022-V2 and includes pre-discovery observations (reported after the discovery observations) made on Aug. 12.6 UT with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala (at mag 20.9-21.6) and on Sept. 18.4 from the Catalina Sky Survey (mag 20.5). The following orbital elements by S. Nakano (Central Bureau) are from 91 observations spanning Aug. 12-Oct. 29 (mean residual 0".5). Epoch = 2022 Dec. 7.0 TT T = 2022 Nov. 27.45634 TT Peri. = 232.77409 e = 0.8933076 Node = 214.85828 2000.0 q = 2.1787758 AU Incl. = 136.53253 a = 20.4211050 AU n = 0.01068034 P = 92.28 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 15.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 09 18 02 38.70 -11 54.3 1.490 2.311 134.8 18.0 19.3 2022 09 28 02 08.83 -21 15.9 1.388 2.277 144.2 14.9 19.1 2022 10 08 01 29.36 -30 35.6 1.370 2.248 142.7 15.6 19.0 2022 10 18 00 43.26 -38 06.6 1.437 2.224 131.2 19.7 19.1 2022 10 28 23 57.12 -42 52.5 1.572 2.204 116.7 23.8 19.2 2022 11 07 23 17.58 -45 13.3 1.751 2.190 102.5 26.2 19.4 2022 11 17 22 47.58 -46 01.5 1.953 2.182 89.5 27.0 19.7 2022 11 27 22 26.68 -46 01.4 2.161 2.179 77.9 26.3 19.9 2022 12 07 22 13.09 -45 40.5 2.363 2.181 67.3 24.6 20.1 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 November 1 (CBET 5185) Daniel W. E. Green