Electronic Telegram No. 5380 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/2024 F2 (PANSTARRS) Y. Ramanjooloo, Institute for Astronomy, University of Hawaii, reports the discovery of another comet in three 45-s w-band survey images obtained in 1".3 seeing with the Pan-STARRS1 1.8-m reflector at Haleakala on Mar. 21 (discovery observations tabulated below). The condensed coma showed a size of about 2".1 (full-width-at-half-maximum), with a possible very faint and slightly broad 2".5 tail in p.a. 282 degrees. 2024 UT R.A. (2000) Decl. Mag. Mar. 21.60554 16 23 11.29 - 5 32 42.7 21.0 21.61410 16 23 11.41 - 5 32 41.1 20.8 21.63135 16 23 11.66 - 5 32 38.0 20.7 After the comet was posted on the Minor Planet Center's PCCP webpage, H. Sato (Bunkyo-ku, Tokyo, Japan) obtained eight stacked 120-s CCD exposures remotely on Apr. 2.75 UT with a 0.51-m f/6.8 astrograph located at Siding Spring, NSW, Australia, showing a moderately condensed coma 8" in diameter with no tail; the magnitude was 20.0 as measured within a circular aperture of radius 4".3. The available astrometry appears on MPEC 2024-G103. The following two-body orbital elements by S. Nakano (Central Bureau) are from 46 observations spanning 2024 Mar. 21-Apr. 7 (mean residual 0".4). Nakano notes that the orbital period is stil uncertain by +/- 2 months at least; there are no close approaches to major planets. T = 2024 Aug. 3.78511 TT Peri. = 113.89634 e = 0.6002958 Node = 138.86713 2000.0 q = 3.9596293 AU Incl. = 13.74121 a = 9.9063983 AU n = 0.03161043 P = 31.18 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 12.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2024 02 20 16 08.77 -06 37.5 4.006 4.111 89.1 13.9 19.9 2024 03 01 16 14.87 -06 21.8 3.847 4.094 97.4 13.9 19.8 2024 03 11 16 19.67 -06 00.4 3.692 4.077 105.9 13.6 19.7 2024 03 21 16 23.03 -05 34.4 3.545 4.062 114.6 12.9 19.6 2024 03 31 16 24.88 -05 05.1 3.409 4.048 123.6 11.9 19.5 2024 04 10 16 25.16 -04 34.1 3.288 4.034 132.6 10.5 19.4 2024 04 20 16 23.93 -04 03.7 3.186 4.022 141.7 8.9 19.4 2024 04 30 16 21.36 -03 36.0 3.105 4.011 150.3 7.1 19.3 2024 05 10 16 17.69 -03 13.5 3.048 4.001 157.7 5.5 19.2 2024 05 20 16 13.29 -02 58.4 3.018 3.992 161.9 4.5 19.2 2024 05 30 16 08.63 -02 52.5 3.014 3.984 160.5 4.9 19.2 2024 06 09 16 04.16 -02 56.9 3.037 3.977 154.6 6.3 19.2 2024 06 19 16 00.33 -03 12.1 3.084 3.971 146.5 8.1 19.2 2024 06 29 15 57.52 -03 37.3 3.155 3.967 137.8 9.9 19.3 2024 07 09 15 55.98 -04 11.6 3.245 3.963 128.9 11.5 19.3 2024 07 19 15 55.88 -04 53.6 3.352 3.961 120.2 12.8 19.4 2024 07 29 15 57.29 -05 41.6 3.472 3.960 111.6 13.8 19.5 2024 08 08 16 00.20 -06 33.9 3.602 3.960 103.3 14.4 19.6 2024 08 18 16 04.56 -07 29.0 3.738 3.961 95.2 14.7 19.6 2024 08 28 16 10.27 -08 25.3 3.878 3.963 87.4 14.8 19.7 2024 09 07 16 17.22 -09 21.7 4.019 3.966 79.8 14.5 19.8 2024 09 17 16 25.30 -10 17.0 4.158 3.971 72.3 14.0 19.9 2024 09 27 16 34.39 -11 10.0 4.293 3.976 65.1 13.2 20.0 2024 10 07 16 44.37 -12 00.1 4.423 3.983 57.9 12.3 20.0 2024 10 17 16 55.14 -12 46.3 4.544 3.991 50.9 11.2 20.1 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2024 CBAT 2024 April 9 (CBET 5380) Daniel W. E. Green