Electronic Telegram No. 5117 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 = P/2005 N11 = P/2015 PO_210 (PANSTARRS-CHRISTENSEN) Using a two-body orbit for comet P/2022 E1 (cf. CBET 5107) from 55 observations spanning 2022 Mar. 2-Apr. 13, S. Nakano (Central Bureau) found three sets of observations in 2005 and 2006 that had not been linked with each other (each night with a different internal designation) in the Minor Planet Center's "isolated tracklet file" (ITF) that appear identical with comet P/2022 E1. The observations on 2005 July 5 and on 2006 May 23 were made with the Mount Lemmon Survey's 1.5-m reflector, and the observations on 2006 June 17 were made with the Spacewatch 0.9-m f/3 reflector of the Steward Observatory at Kitt Peak; the object is assumed to have been asteroidal in appearance on all three nights. The 2005 and 2006 observations had residuals of +0.27 deg in R.A. and -0.04 deg in Decl. from Nakano's unperturbed 2022 orbital elements, with a corresponding correction of Delta(T) = +1.06 days. 2005 UT R.A. (2000) Decl. Mag. July 5.20631 13 36 17.38 +12 08 57.5 21.4 5.20836 13 36 17.42 +12 08 54.7 21.1 5.21042 13 36 17.49 +12 08 54.7 21.4 5.21252 13 36 17.64 +12 08 52.5 22.8 2006 UT R.A. (2000) Decl. Mag. May 23.42764 20 20 37.53 -18 13 43.0 20.4 23.43258 20 20 37.57 -18 13 44.5 21.3 23.43752 20 20 37.68 -18 13 45.5 20.4 23.44260 20 20 37.68 -18 13 46.8 20.6 June 17.41750 20 19 14.54 -20 38 49.8 20.7 17.43486 20 19 14.16 -20 38 57.6 20.8 17.45214 20 19 13.80 -20 39 05.0 20.6 Nakano then contacted R. Weryk (Department of Physics and Astronomy, University of Western Ontario) to ask him to search for possible Pan-STARRS observations of the comet using Nakano's new orbit for P/2022 E1 linking the 2005-2006 and 2022 observations (66 total observations with mean residual 0".3). Weryk noticed that a previously designated object observed with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala on 2015 Aug. 10 and 11 (and given the minor-planet designation 2015 PO_210 when announced on MPS 620107) appears identical with P/2022 E1; those observations are tabulated below, and their previous publication has warranted the name "PANSTARRS" to be added to the name of this comet. 2015 UT R.A. (2000) Decl. Mag. Aug. 10.51769 23 35 20.67 -24 27 40.4 21.7 10.52741 23 35 20.40 -24 27 44.8 21.8 10.53703 23 35 20.16 -24 27 49.6 21.8 10.54674 23 35 19.93 -24 27 54.0 21.6 11.52146 23 34 56.58 -24 35 35.9 21.6 11.53116 23 34 56.32 -24 35 40.5 21.6 11.54084 23 34 56.06 -24 35 45.1 21.5 11.55054 23 34 55.82 -24 35 49.7 21.6 Weryk also identified single-night Pan-STARRS1 observations in the MPC's ITF file from 2014 May 26, as well as single-night Mt. Lemmon observations in the ITF file from 2014 June 22 (neither of which had been designated yet, as was the case also with the 2004-2005 observations in the ITF file). The 2014 ITF observations are tabulated below. 2014 UT R.A. (2000) Decl. Mag. May 26.43540 17 44 20.22 - 8 08 50.2 20.4 26.45013 17 44 19.67 - 8 08 53.1 20.4 26.47967 17 44 18.56 - 8 08 58.8 20.2 June 22.31636 17 25 18.57 -10 18 12.1 19.7 22.32155 17 25 18.33 -10 18 14.2 19.4 22.32673 17 25 18.11 -10 18 16.0 19.6 Nakano provides the following linked orbital elements from the three known apparitions of this comet, from 80 observations spanning 2005-2022 (mean residual 0".4). The comet passed 0.51 AU from Jupiter on 1978 June 3 UT, but there were no other close approaches found to major planets. Epoch = 1997 Sept.29.0 TT T = 1997 Sept.24.54527 TT Peri. = 143.56554 e = 0.3017085 Node = 110.55245 2000.0 q = 2.8193629 AU Incl. = 19.92129 a = 4.0375155 AU n = 0.12148783 P = 8.11 years Epoch = 2005 Dec. 16.0 TT T = 2005 Dec. 25.44585 TT Peri. = 144.90028 e = 0.2851533 Node = 109.03282 2000.0 q = 2.9458904 AU Incl. = 19.89313 a = 4.1210102 AU n = 0.11781445 P = 8.37 years Epoch = 2014 May 23.0 TT T = 2014 May 10.59431 TT Peri. = 144.76016 e = 0.2835267 Node = 109.02639 2000.0 q = 2.9624588 AU Incl. = 19.87618 a = 4.1347791 AU n = 0.11722645 P = 8.41 years Epoch = 2022 Oct. 28.0 TT T = 2022 Oct. 10.16298 TT Peri. = 145.11266 e = 0.2838394 Node = 108.94387 2000.0 q = 2.9561697 AU Incl. = 19.88659 a = 4.1278026 AU n = 0.11752376 P = 8.39 years Epoch = 2031 Feb. 23.0 TT T = 2031 Feb. 18.25228 TT Peri. = 144.58022 e = 0.2845105 Node = 108.86742 2000.0 q = 2.9573192 AU Incl. = 19.89566 a = 4.1332808 AU n = 0.11729020 P = 8.40 years Epoch = 2039 June 21.0 TT T = 2039 June 21.99258 TT Peri. = 144.27618 e = 0.2857162 Node = 108.82972 2000.0 q = 2.9340092 AU Incl. = 19.94008 a = 4.1076241 AU n = 0.11839082 P = 8.32 years Epoch = 2047 Oct. 17.0 TT T = 2047 Oct. 28.66529 TT Peri. = 144.56542 e = 0.2849489 Node = 108.74523 2000.0 q = 2.9424071 AU Incl. = 19.93135 a = 4.1149606 AU n = 0.11807435 P = 8.35 years The following ephemeris by the undersigned from the above orbital elements updates that on CBET 5107 and uses photometric power-law parameters H = 12.5 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 04 11 15 18.02 +09 46.7 2.233 3.107 144.9 10.7 19.2 2022 04 21 15 12.87 +10 27.1 2.178 3.092 150.4 9.2 19.1 2022 05 01 15 06.47 +10 52.3 2.146 3.077 152.8 8.6 19.0 2022 05 11 14 59.49 +10 57.8 2.140 3.063 151.2 9.1 19.0 2022 05 21 14 52.70 +10 41.3 2.157 3.050 146.2 10.6 19.0 2022 05 31 14 46.77 +10 02.8 2.197 3.038 139.2 12.6 19.0 2022 06 10 14 42.29 +09 04.1 2.257 3.026 131.5 14.6 19.1 2022 06 20 14 39.62 +07 48.4 2.334 3.015 123.4 16.3 19.1 2022 06 30 14 38.94 +06 19.4 2.426 3.005 115.4 17.8 19.2 2022 07 10 14 40.29 +04 40.6 2.528 2.996 107.6 18.9 19.3 2022 07 20 14 43.58 +02 55.3 2.639 2.988 100.0 19.6 19.4 2022 07 30 14 48.68 +01 06.1 2.755 2.981 92.7 19.9 19.4 2022 08 09 14 55.44 -00 44.7 2.874 2.975 85.7 19.9 19.5 2022 08 19 15 03.68 -02 35.5 2.994 2.969 78.9 19.5 19.6 2022 08 29 15 13.27 -04 24.6 3.112 2.965 72.2 18.9 19.7 2022 09 08 15 24.06 -06 11.0 3.228 2.961 65.8 18.1 19.8 2022 09 18 15 35.91 -07 53.4 3.340 2.959 59.5 17.0 19.8 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 April 25 (CBET 5117) Daniel W. E. Green