Electronic Telegram No. 5144 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 L4 (PANSTARRS) An apparently asteroidal object discovered on June 4 (discovery observations tabulated below) in images obtained with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala, HI, USA, has been found to show cometary activity. 2022 UT R.A. (2000) Decl. Mag. June 4.39626 17 04 16.67 -12 19 59.4 21.4 4.40654 17 04 15.08 -12 20 04.0 21.0 4.41688 17 04 13.46 -12 20 08.1 21.8 4.42718 17 04 11.89 -12 20 12.2 20.8 4.48439 17 04 02.91 -12 20 36.0 21.5 4.48502 17 04 02.81 -12 20 36.4 21.3 R. Weryk, Department of Physics and Astronomy, University of Western Ontario, writes that he and R. Wainscoat obtained three 60-s gri-band images with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea (queue observer L. Wells; coordinator H. Flewelling) on June 27.26 UT that show a condensed head of size 0".8 (full-width-at-half-maximum) in 0".7 seeing with a clear, braod tail 4" long spanning p.a. 60-110 degrees. Twenty-six stacked 60-s CCD exposures taken remotely by H. Sato (Tokyo, Japan) on June 20.54-20.55 UT with a 0.51-m f/6.8 astrograph located at Siding Spring show the object to be stellar in appearance; the magnitude was 20.7 as measured within a circular aperture of radius 3".2. The available astrometry appears on MPEC 2022-M104. The following parabolic orbital elements by S. Nakano (Central Bureau) are from 43 observations spanning June 4-27 (mean residual 0".4), and suggest that the comet passed 3.25 AU from Jupiter on 2021 Aug. 24 UT. T = 2021 Dec. 9.94711 TT Peri. = 125.56866 Node = 66.02580 2000.0 q = 3.0207838 AU Incl. = 141.28959 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 14.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 05 21 17 40.73 -10 39.6 2.487 3.412 151.7 8.1 20.2 2022 05 31 17 15.60 -11 49.6 2.468 3.458 165.2 4.3 20.3 2022 06 10 16 49.95 -12 57.5 2.504 3.505 168.8 3.2 20.4 2022 06 20 16 25.57 -13 59.9 2.595 3.554 157.3 6.3 20.5 2022 06 30 16 03.91 -14 55.4 2.736 3.605 143.6 9.6 20.6 2022 07 10 15 45.77 -15 45.2 2.918 3.657 130.2 12.3 20.8 2022 07 20 15 31.37 -16 30.9 3.130 3.711 117.6 14.0 21.0 2022 07 30 15 20.48 -17 14.6 3.362 3.766 105.7 15.0 21.2 2022 08 09 15 12.71 -17 57.7 3.607 3.822 94.5 15.3 21.4 2022 08 19 15 07.58 -18 41.1 3.854 3.880 83.9 15.0 21.6 2022 08 29 15 04.62 -19 25.6 4.098 3.939 73.8 14.3 21.8 2022 09 08 15 03.45 -20 11.2 4.334 3.998 64.1 13.1 22.0 2022 09 18 15 03.70 -20 58.0 4.556 4.059 54.7 11.7 22.2 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 June 30 (CBET 5144) Daniel W. E. Green