Electronic Telegram No. 5165 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 P2 (ZTF) Bryce T. Bolin, Goddard Space Flight Center, reports that a comet has been discovered in images taken with the 1.2-m Schmidt telescope at Palomar in a survey called the "Zwicky Transient Facility" (ZTF) on Aug. 15 and 16 UT (discovery observations tabulated below). The object then showed a coma about 4" wide and a broad tail about 20" long in p.a. about 272 degrees; r-band photometry (5" radius aperture) measured by Q.-z. Ye (University of Maryland): Aug. 15.499 UT, about 18.5; 16.503, 17.8. 2022 UT R.A. (2000) Decl. Mag. Aug. 15.50171 7 00 30.32 +26 53 33.3 18.5 15.50410 7 00 30.68 +26 53 32.0 15.50650 7 00 31.02 +26 53 31.5 15.50889 7 00 31.38 +26 53 30.2 16.50307 7 03 00.05 +26 46 51.9 17.8 16.50546 7 03 00.41 +26 46 50.7 16.50786 7 03 00.77 +26 46 50.2 After the comet was posted on the Minor Planet Center's PCCP webpage, other CCD astrometrists commented on the cometary appearance. Twelve stacked 60-s exposures taken remotely by H. Sato, Tokyo, Japan, on Aug. 19.51 UT with a 0.61-m f/6.5 astrograph located at the Sierra Remote Observatory near Auberry, CA, USA, show a strongly condensed coma 8" in diameter with no tail; the magnitude was 18.1 as measured within a circular aperture of radius 3".8. Fifty stacked 15-s exposures taken by L. Buzzi, Varese, Italy, on Aug. 20.11 UT with a 0.84-m f/3.5 reflector (and measured by Buzzi and A. Aletti) show a moderately condensed coma 10" wide and a broad tail at least 20" long in p.a. 295 degrees; the magnitude was given as 17.5. The available astrometry appears on MPEC 2022-Q201. The following elliptical orbital elements by S. Nakano (Central Bureau) are from 57 observations spanning 2022 Aug. 15-29 (mean residual 0".6); he notes that the observations can be satisfied with similar residuals by a parabolic orbit. T = 2022 July 7.39280 TT Peri. = 136.23686 e = 0.5046327 Node = 290.91908 2000.0 q = 1.9593097 AU Incl. = 12.51972 a = 3.9552662 AU n = 0.12529695 P = 7.866 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 11.5 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 08 09 06 44.04 +27 33.3 2.700 1.980 36.6 17.8 16.6 2022 08 19 07 09.17 +26 29.6 2.654 1.994 40.4 19.2 16.6 2022 08 29 07 33.14 +25 11.8 2.604 2.012 44.5 20.6 16.6 2022 09 08 07 55.81 +23 42.0 2.551 2.033 48.7 21.9 16.6 2022 09 18 08 17.06 +22 02.6 2.494 2.058 53.3 23.1 16.6 2022 09 28 08 36.81 +20 15.9 2.432 2.085 58.2 24.1 16.6 2022 10 08 08 54.96 +18 24.2 2.365 2.115 63.4 25.0 16.6 2022 10 18 09 11.41 +16 29.8 2.294 2.148 69.0 25.7 16.6 2022 10 28 09 26.06 +14 34.8 2.219 2.184 75.0 26.1 16.6 2022 11 07 09 38.76 +12 41.5 2.140 2.221 81.5 26.2 16.6 2022 11 17 09 49.34 +10 51.9 2.059 2.261 88.5 25.9 16.6 2022 11 27 09 57.59 +09 08.2 1.978 2.302 96.1 25.2 16.6 2022 12 07 10 03.28 +07 32.6 1.898 2.344 104.3 24.0 16.6 2022 12 17 10 06.21 +06 07.5 1.823 2.389 113.2 22.3 16.6 2022 12 27 10 06.21 +04 55.3 1.756 2.434 122.8 19.8 16.6 2023 01 06 10 03.27 +03 58.1 1.702 2.480 133.1 16.8 16.6 2023 01 16 09 57.64 +03 17.6 1.665 2.528 144.0 13.2 16.6 2023 01 26 09 49.84 +02 54.5 1.650 2.576 155.0 9.3 16.7 2023 02 05 09 40.76 +02 47.6 1.660 2.625 164.9 5.6 16.8 2023 02 15 09 31.48 +02 54.1 1.698 2.674 168.8 4.1 16.9 2023 02 25 09 23.06 +03 09.8 1.764 2.724 162.2 6.4 17.1 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 August 31 (CBET 5165) Daniel W. E. Green