Electronic Telegram No. 5242 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 364P/PANSTARRS This comet (cf. CBETs 3558, 4475, 4589) is brightening and may reach total visual magnitude 11 in early April. The following revised orbital elements by S. Nakano (Central Bureau) are from 868 observations spanning 2013-2023 (mean residual 0".6), with corresponding non-gravitational parameters A1 = -0.004 +/- 0.002 and A2 = -0.00049 +/- 0.00002. The comet will pass 0.12 AU from the earth on 2023 Apr. 7 UT. Epoch = 2013 Aug. 16.0 TT T = 2013 Aug. 6.93215 TT Peri. = 211.97250 e = 0.7221121 Node = 46.20961 2000.0 q = 0.8001467 AU Incl. = 12.14764 a = 2.8793864 AU n = 0.20172241 P = 4.89 years Epoch = 2018 June 11.0 TT T = 2018 June 24.36599 TT Peri. = 211.92790 e = 0.7227341 Node = 46.22819 2000.0 q = 0.7978528 AU Incl. = 12.15535 a = 2.8775722 AU n = 0.20191321 P = 4.88 years Epoch = 2023 May 16.0 TT T = 2023 May 14.01852 TT Peri. = 212.02027 e = 0.7217175 Node = 46.14801 2000.0 q = 0.8012868 AU Incl. = 12.13762 a = 2.8794004 AU n = 0.20172094 P = 4.89 years Epoch = 2028 Apr. 19.0 TT T = 2028 Apr. 21.84353 TT Peri. = 213.05712 e = 0.7144900 Node = 45.45185 2000.0 q = 0.8301983 AU Incl. = 11.79560 a = 2.9077727 AU n = 0.19877574 P = 4.96 years Epoch = 2033 Mar. 24.0 TT T = 2033 Apr. 8.21363 TT Peri. = 213.18438 e = 0.7149865 Node = 45.38114 2000.0 q = 0.8283503 AU Incl. = 11.78449 a = 2.9063550 AU n = 0.19892121 P = 4.96 years Epoch = 2038 Feb. 26.0 TT T = 2038 Mar. 17.46754 TT Peri. = 213.59673 e = 0.7183346 Node = 45.04608 2000.0 q = 0.8150587 AU Incl. = 11.74930 a = 2.8937124 AU n = 0.20022625 P = 4.92 years Epoch = 2043 Jan. 31.0 TT T = 2043 Feb. 15.72118 TT Peri. = 213.58192 e = 0.7192980 Node = 45.05602 2000.0 q = 0.8114475 AU Incl. = 11.75871 a = 2.8907794 AU n = 0.20053106 P = 4.92 years Epoch = 2048 Jan. 5.0 TT T = 2048 Jan. 17.06465 TT Peri. = 213.61755 e = 0.7183463 Node = 45.01302 2000.0 q = 0.8152017 AU Incl. = 11.74161 a = 2.8943399 AU n = 0.20016114 P = 4.92 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 16.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2023 02 25 13 31.96 +21 57.9 0.524 1.409 134.7 30.0 15.8 2023 03 02 13 43.41 +23 05.0 0.458 1.356 135.4 30.9 15.4 2023 03 07 13 56.89 +24 23.3 0.395 1.303 135.3 32.4 14.9 2023 03 12 14 13.61 +25 54.6 0.336 1.251 134.2 34.7 14.4 2023 03 17 14 35.63 +27 40.5 0.280 1.199 131.6 38.4 13.9 2023 03 22 15 06.76 +29 39.4 0.227 1.147 127.0 43.9 13.3 2023 03 27 15 54.14 +31 33.7 0.181 1.097 119.2 52.5 12.6 2023 04 01 17 09.22 +32 05.2 0.143 1.049 106.5 65.9 11.9 2023 04 06 18 56.09 +27 49.3 0.122 1.002 87.5 85.5 11.4 2023 04 11 20 44.07 +17 23.5 0.126 0.959 66.6 106.4 11.4 2023 04 16 22 01.10 +06 47.2 0.153 0.919 52.8 119.6 11.6 2023 04 21 22 50.26 -00 22.6 0.195 0.883 46.9 123.8 12.0 2023 04 26 23 23.07 -04 40.9 0.244 0.853 45.5 122.7 12.4 2023 05 01 23 46.93 -07 10.3 0.299 0.829 46.2 118.8 12.7 2023 05 06 00 05.78 -08 30.5 0.356 0.812 47.6 113.5 13.0 2023 05 11 00 21.76 -09 04.5 0.415 0.803 49.2 107.7 13.3 2023 05 16 00 36.00 -09 06.6 0.475 0.802 51.0 101.6 13.6 2023 05 26 01 01.37 -08 11.9 0.591 0.825 54.5 89.8 14.2 2023 06 05 01 23.93 -06 37.5 0.697 0.876 58.1 79.4 14.8 2023 06 15 01 44.07 -04 52.8 0.788 0.950 62.1 70.8 15.3 2023 06 25 02 01.59 -03 15.0 0.860 1.039 66.6 63.9 15.8 2023 07 05 02 16.28 -01 52.3 0.915 1.137 71.9 58.2 16.3 2023 07 15 02 27.90 -00 48.5 0.952 1.240 78.0 53.3 16.6 2023 07 25 02 36.09 -00 05.1 0.973 1.345 85.1 48.8 17.0 2023 08 04 02 40.48 +00 17.8 0.982 1.451 93.2 44.3 17.3 2023 08 14 02 40.67 +00 20.9 0.983 1.556 102.4 39.5 17.5 2023 08 24 02 36.26 +00 05.5 0.981 1.659 112.8 34.2 17.7 2023 09 03 02 27.17 -00 25.2 0.982 1.761 124.4 28.2 17.9 2023 09 13 02 13.78 -01 06.3 0.994 1.861 137.0 21.7 18.1 2023 09 23 01 57.17 -01 50.2 1.023 1.958 150.1 14.8 18.4 2023 10 03 01 39.15 -02 28.0 1.077 2.054 162.6 8.4 18.7 2023 10 13 01 21.77 -02 52.5 1.158 2.147 169.3 5.0 19.0 2023 10 23 01 06.76 -02 59.6 1.268 2.237 162.6 7.7 19.3 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 March 28 (CBET 5242) Daniel W. E. Green