Electronic Telegram No. 5210 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/2012 Q3 = P/2021 L4 (PANSTARRS) K. Ly (El Monte, CA, USA) and S. Deen (Simi Valley, CA, USA) report the identification of images of comet P/2021 L4 (cf. CBET 4986) in images taken in 2012 with the 3.6-m Canada-France-Hawaii Telescope at Mauna Key by M. Alexandersen (observations tabulated below). The comet appears completely asteroidal with no sign of activity in those images. 2012 UT R.A. (2000) Decl. Mag. Observer Aug. 18.50046 1 39 27.19 +26 42 15.1 23.4 Alexandersen 18.53950 1 39 27.47 +26 42 22.1 23.4 " 28.46759 1 39 50.50 +27 04 30.1 23.3 " Sep. 12.39827 1 36 31.48 +27 08 23.5 23.0 " 14.43438 1 35 42.91 +27 05 46.9 23.0 " The 2012 observations show a residual of only +2".5 (mainly in R.A.) from an orbit by S. Nakano (Central Bureau) on NK 4871. The following linked orbital elements by Nakano are from 49 observations spanning 2012-2022 (mean residual 0".2). There have been no recent close approaches to major planets since an approach to 1.89 AU from Jupiter in 1948. Epoch = 2014 Jan. 23.0 TT T = 2014 Jan. 19.07135 TT Peri. = 235.29274 e = 0.1210695 Node = 243.29376 2000.0 q = 2.7846295 AU Incl. = 16.96443 a = 3.1682022 AU n = 0.17477719 P = 5.64 years Epoch = 2019 Aug. 25.0 TT T = 2019 Sept. 5.66915 TT Peri. = 234.92054 e = 0.1191406 Node = 243.23503 2000.0 q = 2.7899378 AU Incl. = 16.95981 a = 3.1672907 AU n = 0.17485263 P = 5.64 years Epoch = 2025 May 5.0 TT T = 2025 Apr. 15.02238 TT Peri. = 233.02170 e = 0.1160790 Node = 243.14770 2000.0 q = 2.8022479 AU Incl. = 16.96570 a = 3.1702470 AU n = 0.17460812 P = 5.64 years Epoch = 2030 Dec. 5.0 TT T = 2030 Dec. 6.66851 TT Peri. = 233.05093 e = 0.1142186 Node = 243.11013 2000.0 q = 2.8084330 AU Incl. = 16.96174 a = 3.1705711 AU n = 0.17458134 P = 5.65 years Epoch = 2036 Aug. 15.0 TT T = 2036 July 28.20768 TT Peri. = 232.51158 e = 0.1082023 Node = 242.83811 2000.0 q = 2.8299725 AU Incl. = 16.99695 a = 3.1733345 AU n = 0.17435335 P = 5.65 years Epoch = 2042 Mar. 17.0 TT T = 2042 Mar. 27.79540 TT Peri. = 232.98472 e = 0.1067752 Node = 242.80387 2000.0 q = 2.8355772 AU Incl. = 16.99336 a = 3.1745392 AU n = 0.17425411 P = 5.66 years Epoch = 2047 Nov. 26.0 TT T = 2047 Dec. 7.67964 TT Peri. = 235.33856 e = 0.1012796 Node = 242.28553 2000.0 q = 2.8544651 AU Incl. = 17.00376 a = 3.1761438 AU n = 0.17412208 P = 5.66 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. 2023 05 16 23 32.77 +13 04.3 3.847 3.401 56.8 14.4 21.2 2023 06 05 23 50.84 +15 56.1 3.590 3.384 70.2 16.4 21.1 2023 06 25 00 05.20 +18 36.2 3.310 3.366 84.4 17.5 20.9 2023 07 15 00 14.52 +20 54.4 3.024 3.347 99.6 17.4 20.6 2023 08 04 00 17.33 +22 36.0 2.753 3.328 116.2 15.9 20.4 2023 08 24 00 12.68 +23 20.9 2.524 3.308 134.0 12.7 20.2 2023 09 13 00 01.40 +22 48.0 2.368 3.287 151.4 8.4 20.0 2023 10 03 23 47.24 +20 53.3 2.311 3.266 159.4 6.2 20.0 2023 10 23 23 35.83 +18 06.9 2.362 3.245 147.4 9.5 20.0 2023 11 12 23 31.47 +15 21.2 2.511 3.223 128.6 13.9 20.1 2023 12 02 23 35.50 +13 17.9 2.728 3.200 109.9 16.8 20.2 2023 12 22 23 47.03 +12 13.7 2.981 3.178 92.4 18.0 20.4 2024 01 11 00 04.49 +12 06.4 3.241 3.155 76.2 17.6 20.5 2024 01 31 00 26.36 +12 45.4 3.484 3.132 61.3 16.0 20.7 2024 02 20 00 51.46 +13 58.0 3.694 3.109 47.3 13.5 20.8 2024 07 29 04 58.06 +23 23.2 3.482 2.938 50.2 15.4 20.4 2024 08 18 05 26.47 +22 54.1 3.237 2.919 62.9 18.0 20.2 2024 09 07 05 51.32 +21 54.6 2.966 2.902 76.6 19.7 20.0 2024 09 27 06 10.96 +20 27.0 2.680 2.885 91.5 20.3 19.7 2024 10 17 06 23.45 +18 35.3 2.399 2.870 108.1 19.3 19.5 2024 11 06 06 26.76 +16 25.6 2.149 2.857 127.0 16.1 19.2 2024 11 26 06 19.83 +14 08.1 1.960 2.844 147.8 10.7 19.0 2024 12 16 06 04.62 +12 00.7 1.867 2.833 166.6 4.6 18.9 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 January 27 (CBET 5210) Daniel W. E. Green