Electronic Telegram No. 5205 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 Y1 (HOGAN) Joshua Hogan, Lunar and Planetary Laboratory, University of Arizona, reports the discovery of a comet on images taken with the Mt. Lemmon 1.5-m reflector on Dec. 24 UT (discovery observations tabulated below), noting a condensed coma of size 6" and a 6" tail about 4".5 wide. 2022 UT R.A. (2000) Decl. Mag. Observer Dec. 24.34157 7 46 38.57 +20 21 58.0 19.7 Hogan 24.34722 7 46 38.37 +20 21 55.7 19.5 " 24.35287 7 46 38.16 +20 21 53.7 19.7 " 24.35854 7 46 38.00 +20 21 51.7 19.8 " K. Wierzchos, Lunar and Planetary Laboratory, writes that three 60-s unfiltered follow-up exposures taken on 2022 Dec. 25.4 UT with the Steward Observatory 1.0-m reflector at Mt. Lemmon show a diffuse object with a condensed coma and a pseudo-nucleus about 3" in diameter, accompanied by a broad tail spanning p.a. 290-340 degrees (centered in p.a. about 315 degrees). After the object was posted on the Minor Planet Center's PCCP webpage, H. Sato (Tokyo, Japan) wrote to the Central Bureau stating that ten stacked 120-s exposures taken remotely with a 0.51-m f/6.8 astrograph located at Mayhill, NM, USA, on 2022 Dec. 26.3 show a strongly condensed object with an outer coma 8" in diameter and no tail; the magnitude was 19.3 as measured within a circular aperture of radius 4".9. The available astrometry (including pre-discovery Mt. Lemmon observations going back to 2022 Nov. 5.5 UT, when the comet was measured to be at mag 20.8-21.6) appears on MPEC 2023-A37. The following elliptical orbital elements by S. Nakano (Central Bureau) are from 84 observations spanning 2022 Nov. 5-2023 Jan. 11 (mean residual 0".3), and they indicate no close approach to major planets. T = 2022 Nov. 27.23575 TT Peri. = 174.74244 e = 0.7641965 Node = 285.91529 2000.0 q = 2.9577808 AU Incl. = 18.85980 a = 12.5434142 AU n = 0.02218607 P = 44.425 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 13.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 12 07 07 53.28 +22 08.2 2.149 2.959 138.4 12.8 18.9 2022 12 17 07 50.18 +21 06.8 2.075 2.963 149.1 9.8 18.9 2022 12 27 07 45.15 +20 05.9 2.025 2.969 160.3 6.4 18.8 2023 01 06 07 38.83 +19 06.0 2.002 2.978 171.4 2.8 18.8 2023 01 16 07 32.06 +18 07.9 2.008 2.990 175.1 1.6 18.8 2023 01 26 07 25.73 +17 12.8 2.044 3.003 164.4 5.1 18.9 2023 02 05 07 20.65 +16 21.6 2.107 3.020 153.3 8.4 19.0 2023 02 15 07 17.38 +15 34.9 2.195 3.038 142.5 11.4 19.1 2023 02 25 07 16.24 +14 52.7 2.304 3.059 132.3 13.8 19.2 2023 03 07 07 17.31 +14 14.1 2.431 3.083 122.7 15.7 19.3 2023 03 17 07 20.50 +13 38.0 2.572 3.108 113.7 17.0 19.5 2023 03 27 07 25.60 +13 03.1 2.723 3.135 105.2 17.9 19.6 2023 04 06 07 32.39 +12 28.0 2.881 3.165 97.1 18.3 19.8 2023 04 16 07 40.59 +11 51.3 3.043 3.196 89.5 18.3 20.0 2023 04 26 07 49.96 +11 12.2 3.207 3.229 82.3 18.0 20.1 2023 05 06 08 00.29 +10 29.7 3.371 3.264 75.3 17.4 20.2 2023 05 16 08 11.35 +09 43.4 3.532 3.301 68.6 16.6 20.4 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 January 12 (CBET 5205) Daniel W. E. Green