Electronic Telegram No. 5146 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/2022 M1 (PANSTARRS) R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reports the discovery of another comet has been found in images obtained on June 29 with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala, HI, USA (discovery observations tabulated below); four stacked 45-s w-band survey images show a condensed head of size 1".8 (full-width-at- half-maximum in 1".3 seeing) with an apparent tail (point-spread-function asymmetry) extending 3" in p.a. 250 deg. 2022 UT R.A. (2000) Decl. Mag. June 29.56544 22 44 03.35 - 9 54 45.6 21.1 29.57819 22 44 03.93 - 9 54 38.9 20.7 29.59101 22 44 04.52 - 9 54 32.0 21.0 29.60377 22 44 05.09 - 9 54 25.4 20.7 R. Wainscoat and Weryk obtained three 60-s gri-band follow-up exposures with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea on June 30.6 UT (queue observer C. Cunningham; queue coordinator T. Burdullis), which show a very condensed coma of size 0".9 (FWHM) in 0".7 seeing and a clear tail at least 18" long toward p.a. 245 degrees. Weryk adds that three 120-s unfiltered exposures taken on July 5.55 by J. Fairlamb and M. McCormack using the University of Hawaii 2.2-m telescope at Mauna Kea show the very condensed head to be 1".6 across (FWHM) in 1".2 seeing, with a clear tail > 25" long in p.a. 245 degrees. After the object was posted on the Minor Planet Center's PCCP webpage, H. Sato (Tokyo, Japan) reported that ten stacked 120-s CCD exposures taken remotely on July 2.4 UT with a 0.43-m f/6.8 astrograph located at Mayhill, NM, USA, show a strongly condensed coma 6" in diameter with a straight tail 25" long toward p.a. 230 degrees; the magnitude was 20.1 as measured within a circular aperture of radius 5".7. Weryk identified apparently asteroidal, single-night pre-discovery observations in the MPC's "isolated tracklet file" that were made on May 31.44-31.46 UT at Mt. Lemmon (mag 20.3-20.9) and on June 15.30-15.36 with the 4-m Cerro Tololo reflector (+ DECam). The available astrometry appear on MPEC 2022-N46. The following preliminary elliptical orbital elements by S. Nakano (Central Bureau) are from 26 observations spanning May 31-July 6 (mean residual 0".2); the orbital period is still uncertain by about two weeks, but the orbit suggests that the comet passed 0.55 AU from Jupiter in 2013 Oct. Nakano was unable to find earlier observations in archival astrometry files. T = 2022 Aug. 2.22340 TT Peri. = 4.40078 e = 0.5793121 Node = 322.92923 2000.0 q = 2.0620636 AU Incl. = 7.02704 a = 4.9016467 AU n = 0.09082200 P = 10.85 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 16.0 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 06 20 22 35.34 -11 22.3 1.493 2.099 112.2 26.6 20.1 2022 06 30 22 44.40 -09 50.9 1.391 2.084 119.1 25.2 19.9 2022 07 10 22 51.03 -08 26.3 1.300 2.073 126.6 23.2 19.7 2022 07 20 22 54.99 -07 10.4 1.220 2.066 134.7 20.5 19.6 2022 07 30 22 56.11 -06 05.1 1.155 2.062 143.6 17.0 19.5 2022 08 09 22 54.47 -05 11.6 1.107 2.063 153.2 12.8 19.4 2022 08 19 22 50.55 -04 29.9 1.078 2.068 163.2 8.1 19.3 2022 08 29 22 45.13 -03 59.0 1.070 2.076 173.1 3.4 19.3 2022 09 08 22 39.37 -03 36.0 1.085 2.089 173.2 3.3 19.4 2022 09 18 22 34.49 -03 17.1 1.123 2.105 163.4 7.8 19.5 2022 09 28 22 31.43 -02 58.3 1.182 2.125 153.3 12.2 19.6 2022 10 08 22 30.84 -02 36.0 1.261 2.149 143.6 16.0 19.8 2022 10 18 22 32.93 -02 07.4 1.359 2.176 134.4 19.1 20.0 2022 10 28 22 37.59 -01 31.0 1.471 2.206 125.9 21.4 20.3 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 July 8 (CBET 5146) Daniel W. E. Green