Electronic Telegram No. 5107 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 E1 (CHRISTENSEN) Eric J. Christensen, University of Arizona, reports the discovery of a comet on 30-s CCD exposures taken on Mar. 2 with the 1.5-m reflector at Mt. Lemmon; four co-added images show a condensed 5" coma with a 10" tail toward p.a. 290 degrees. The discovery observations are tabulated below. 2022 UT R.A. (2000) Decl. Mag. Observer Mar. 2.44874 15 19 22.63 + 6 20 57.0 20.6 Christensen 2.45386 15 19 22.78 + 6 20 58.2 20.5 " 2.45898 15 19 22.88 + 6 20 59.5 20.7 " 2.46411 15 19 22.98 + 6 21 00.8 20.3 " 2.51180 15 19 24.01 + 6 21 14.2 20.8 " 2.51880 15 19 24.14 + 6 21 16.5 20.4 " After the comet was posted on the Minor Planet Center's PCCP webpage, other CCD astrometrists also commented on the cometary appearance. L. Buzzi, Varese, Italy, writes that ninety stacked 60-s exposures taken on Mar. 7.1 UT by A. Aletti and himself with a 0.84-m f/3.5 reflector show a moderately condensed coma 6" wide with a faint extension toward p.a. 290 degrees. Ten stacked 120-s exposures taken remotely on Mar. 8.5 by Hidetaka Sato (Tokyo, Japan) using a 0.43-m f/6.8 astrograph near Mayhill, NM, USA, show a strongly condensed, fuzzy coma 6" in diameter with no tail; the magnitude was 20.5 as measured within a circular aperture of radius 5".7. Twenty-five stacked 60-s exposures taken at Shinshiro, Japan, on Mar. 8.7 by T. Ikemura with a 0.38-m f/4.2 reflector (and measured by Hirohisa Sato) show a moderately condensed coma about 6" in diameter but with no tail. R. Weryk, Department of Physics and Astronomy, University of Western Ontario, notes that four 45-s w-band survey images obtained with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala, HI, on Mar. 10.6 in 1".8 seeing show a very condensed, tiny coma of size 1".9 (full-width-at-half-maximum) with an obvious tail 8" long in p.a. 280 degrees. The available astrometry appears on MPEC 2022-E167. The following preliminary elliptical orbital elements by S. Nakano (Central Bureau) are from 45 observations spanning Mar. 2-10 (mean residual 0".3). While Nakano was unable to identify other observations in archival data, he notes that the orbital period has a lot of uncertainty still, due to the short arc. T = 2022 Oct. 8.53036 TT Peri. = 144.51077 e = 0.2865149 Node = 109.13175 2000.0 q = 2.9641115 AU Incl. = 19.88702 a = 4.1544127 AU n = 0.11639642 P = 8.47 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 13.0 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 01 21 14 50.80 +04 34.2 3.240 3.258 82.3 17.4 20.7 2022 01 31 15 00.02 +04 44.4 3.089 3.238 89.7 17.7 20.6 2022 02 10 15 07.97 +05 05.6 2.939 3.218 97.4 17.7 20.4 2022 02 20 15 14.44 +05 37.5 2.794 3.199 105.2 17.3 20.3 2022 03 02 15 19.21 +06 18.9 2.656 3.181 113.3 16.6 20.1 2022 03 12 15 22.04 +07 08.0 2.528 3.163 121.5 15.5 20.0 2022 03 22 15 22.81 +08 01.8 2.414 3.146 129.7 14.1 19.9 2022 04 01 15 21.45 +08 56.4 2.317 3.129 137.7 12.4 19.8 2022 04 11 15 18.05 +09 46.7 2.239 3.113 144.9 10.7 19.7 2022 04 21 15 12.93 +10 27.1 2.184 3.098 150.4 9.2 19.6 2022 05 01 15 06.56 +10 52.3 2.153 3.083 152.8 8.6 19.6 2022 05 11 14 59.61 +10 57.9 2.146 3.069 151.2 9.1 19.5 2022 05 21 14 52.84 +10 41.6 2.163 3.056 146.2 10.6 19.5 2022 05 31 14 46.93 +10 03.3 2.203 3.044 139.3 12.6 19.5 2022 06 10 14 42.46 +09 04.9 2.263 3.032 131.5 14.5 19.6 2022 06 20 14 39.81 +07 49.5 2.341 3.022 123.4 16.3 19.6 2022 06 30 14 39.13 +06 20.8 2.432 3.012 115.4 17.7 19.7 2022 07 10 14 40.47 +04 42.2 2.535 3.003 107.6 18.8 19.8 2022 07 20 14 43.76 +02 57.2 2.646 2.995 100.0 19.5 19.9 2022 07 30 14 48.84 +01 08.3 2.762 2.988 92.7 19.8 20.0 2022 08 09 14 55.58 -00 42.3 2.881 2.982 85.7 19.8 20.0 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 March 11 (CBET 5107) Daniel W. E. Green