Electronic Telegram No. 5188 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 U3 (BOK) Hannes Groeller and Cassandra Lejoly, University of Arizona, report the discovery of a comet on mosaic CCD images obtained in the course of the "Bok NEO Survey" (cf. CBET 5103) with the Bok 2.25-m reflector at Kitt Peak on Oct. 31 (discovery observations tabulated below); four 30-s images show a condensed 6" coma and a tail about 6" long in p.a. about 230 degrees. 2022 UT R.A. (2000) Decl. Mag. Observer Oct. 31.26146 1 46 07.27 +45 19 34.3 19.6 Groeller 31.26645 1 46 07.08 +45 19 33.3 19.9 " 31.27142 1 46 06.94 +45 19 32.3 19.8 " 31.27638 1 46 06.80 +45 19 31.4 19.9 " After the comet was posted on the Minor Planet Center's PCCP webpage, other CCD astrometrists have also reported cometary appearance to the Central Bureau. Ten stacked 120-s exposures taken remotely on Nov. 1.2 UT by H. Sato (Bunkyo-ku, Tokyo, Japan) with a 0.43-m f/6.8 astrograph located at Mayhill, NM, USA, show a strongly condensed object with an outer coma 8" in diameter and a tail 10" long toward p.a. 270 degrees; the magnitude was 19.0 as measured within a circular aperture of radius 5".7. L. Buzzi, Varese, Italy, writes that two-hundred-ninety-two stacked 30-s exposures taken on Nov. 2.0 by A. Aletti with a 0.36-m f/7.5 reflector in good conditins show a condensed coma 5" in size (about 1".1 larger than nearby stars of similar brightness), elongated in p.a. 230 degrees. Twenty-five 120-s images taken on Nov. 2.9 by M. Jaeger with a 0.3-m telescope at Oed, Austria, show a very condensed 6" coma that is slightly elongated toward p.a. 180 degrees, but with no obvious tail. R. Weryk, Department of Physics and Astronomy, University of Western Ontario, has identified pre-discovery images of this comet in images obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala, HI, on 2021 June 23 (mag 23.2) and 30 (mag 23.9), and on 2021 Nov. 12 (mag 21.4- 22.1), as well as pre-discovery images taken with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala on 2021 Oct. 21 (mag 21.9) and Nov. 16 (mag 21.7), and on 2022 Jan. 12 (mag 21.3) and July 17 (mag 21.3). Weryk notes that the object is too faint to discern any activity levels. The available astrometry appears on MPEC 2022-V83 and includes also pre- discovery observations from Mt. Lemmon Survey images taken on 2022 Sept. 18 (mag 19.8-20.1) and Oct. 19 (mag 19.7-19.9) that were reported to the MPC after the discovery observations above were reported. The following orbital elements by S. Nakano (Central Bureau) are from 73 observations spanning 2021 June 23-2022 Nov. 2 (mean residual 0".4), with corresponding original and future values of 1/a being +0.000053 and +0.000860 AU**-1 (+/- 0.000017). The comet will pass 2.91 AU from Jupiter on 2024 Mar. 16 UT. Epoch = 2024 July 29.0 TT T = 2024 July 28.56632 TT Peri. = 189.10392 e = 1.0017205 Node = 272.78478 2000.0 q = 4.8267351 AU Incl. = 33.65661 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 8.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 09 18 02 03.16 +46 01.1 6.445 7.037 122.6 6.9 18.8 2022 09 28 02 00.23 +46 09.3 6.297 6.986 130.2 6.3 18.7 2022 10 08 01 56.48 +46 07.2 6.167 6.935 137.3 5.6 18.7 2022 10 18 01 52.16 +45 54.1 6.060 6.884 143.2 5.0 18.6 2022 10 28 01 47.60 +45 29.8 5.977 6.833 147.1 4.5 18.6 2022 11 07 01 43.16 +44 55.0 5.920 6.783 148.2 4.4 18.5 2022 11 17 01 39.18 +44 11.2 5.890 6.733 146.0 4.7 18.5 2022 11 27 01 35.97 +43 20.4 5.886 6.683 141.1 5.3 18.4 2022 12 07 01 33.80 +42 25.4 5.907 6.634 134.3 6.1 18.4 2022 12 17 01 32.80 +41 28.7 5.951 6.584 126.6 6.9 18.4 2022 12 27 01 33.07 +40 33.0 6.013 6.536 118.2 7.6 18.4 2023 01 06 01 34.63 +39 40.6 6.091 6.487 109.6 8.2 18.4 2023 01 16 01 37.44 +38 53.2 6.179 6.439 100.9 8.6 18.4 2023 01 26 01 41.43 +38 11.9 6.275 6.391 92.3 8.9 18.4 2023 02 05 01 46.50 +37 37.5 6.374 6.344 83.8 8.9 18.4 2023 02 15 01 52.55 +37 10.1 6.471 6.296 75.5 8.7 18.4 2023 02 25 01 59.47 +36 49.6 6.564 6.250 67.3 8.4 18.5 2023 03 07 02 07.17 +36 35.7 6.649 6.204 59.4 7.9 18.5 2023 03 17 02 15.53 +36 27.6 6.723 6.158 51.8 7.3 18.5 2023 03 27 02 24.48 +36 24.9 6.785 6.112 44.4 6.6 18.4 2023 04 06 02 33.91 +36 26.7 6.831 6.067 37.5 5.8 18.4 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 November 4 (CBET 5188) Daniel W. E. Green