Electronic Telegram No. 5317 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/2023 V6 (PANSTARRS) R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reports the discovery of another comet in images obtained on Nov. 8 UT with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala (discovery observations tabulated below). The four 45-s w-band survey images takein in seeing around 1".5 on Nov. 8.6 show a soft appearance, with the head showing a size of 2".2 (full-width-at-half-maximum) in a stacked image and no tail. 2023 UT R.A. (2000) Decl. Mag. Nov. 8.55523 4 16 33.12 +17 20 31.8 21.1 8.56815 4 16 32.71 +17 20 30.4 21.4 8.58106 4 16 32.31 +17 20 28.8 21.1 8.59829 4 16 31.80 +17 20 27.0 21.1 Pre-discovery observations taken with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala on Oct. 22.4 UT (at mag 21.6-21.7) were subsequently identified in the Minor Planet Center's "isolated tracklet file". Additional pre-discovery Pan-STARRS1 images of the comet were then found going back to Oct. 16.5 (mag 20.9), Oct. 25 (mag 21.0), and Nov. 4 (mag 20.2-21.3). After the comet was posted on the MPC's PCCP webpage, L. Buzzi (Varese, Italy) reported that CCD observations obtained by G. Galli and himself (and measured by Buzzi, Galli, and A. Aletti) with a 0.84-m f/3.5 reflector confirm this to be a comet; seventy-four stacked 30-s images taken on Nov. 11.9 show a somewhat diffuse 5" coma, possibly elongated toward the southwest, while one-hundred-eighty stacked 30-s exposures taken on Nov. 13.1 show a moderately condensed coma 6" wide (mag 20.7), elongated for 5" in p.a. around 255 degrees. The available astrometry appears on MPEC 2023-V262. The following elliptical orbital elements by S. Nakano (Central Bureau) are from 20 observations spanning 2023 Oct. 16-Nov. 13 (mean residual 0".2); while the orbital period is still uncertain, the orbit indicates that the comet passed 0.32 AU from Jupiter in 2020 December UT. T = 2022 Dec. 28.54350 TT Peri. = 195.20466 e = 0.1786978 Node = 190.00975 2000.0 q = 4.3901678 AU Incl. = 3.97501 a = 5.3453746 AU n = 0.07975113 P = 12.36 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 12.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2023 10 23 04 23.63 +17 51.4 3.684 4.508 141.8 7.9 20.1 2023 11 02 04 19.71 +17 33.3 3.611 4.515 152.6 5.8 20.0 2023 11 12 04 14.75 +17 13.7 3.565 4.523 163.6 3.5 20.0 2023 11 22 04 09.15 +16 53.7 3.548 4.531 174.0 1.3 20.0 2023 12 02 04 03.40 +16 34.6 3.562 4.540 171.8 1.8 20.0 2023 12 12 03 57.96 +16 18.0 3.606 4.548 161.0 4.0 20.0 2023 12 22 03 53.29 +16 05.2 3.679 4.557 149.8 6.2 20.1 2024 01 01 03 49.76 +15 57.2 3.779 4.566 138.9 8.1 20.2 2024 01 11 03 47.58 +15 54.6 3.901 4.575 128.2 9.7 20.2 2024 01 21 03 46.90 +15 57.6 4.040 4.584 117.9 10.9 20.3 2024 01 31 03 47.73 +16 05.9 4.192 4.594 108.0 11.8 20.4 2024 02 10 03 50.02 +16 19.0 4.353 4.603 98.5 12.2 20.5 2024 02 20 03 53.69 +16 36.0 4.518 4.613 89.3 12.4 20.6 2024 03 01 03 58.61 +16 56.0 4.682 4.623 80.5 12.2 20.7 2024 03 11 04 04.64 +17 18.2 4.843 4.633 72.0 11.8 20.8 2024 03 21 04 11.66 +17 41.6 4.997 4.643 63.8 11.1 20.8 2024 03 31 04 19.51 +18 05.2 5.142 4.654 55.8 10.2 20.9 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 November 16 (CBET 5317) Daniel W. E. Green