Electronic Telegram No. 5472 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 T5 (ATLAS) An apparently asteroidal object discovered on CCD images taken on Oct. 2.9 UT with a 0.5-m f/2 Schmidt reflector at Sutherland, South Africa, in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program has been found to show cometary appearance by CCD astrometrists elsewhere after the object was placed on the Minor Planet Center's NEOCP and PCCP webpages. The discovery observations are tabulated below. 2024 UT R.A. (2000) Decl. Mag. Oct. 2.92918 1 23 12.65 -54 20 38.1 19.2 2.93099 1 23 12.52 -54 20 37.6 18.9 2.93376 1 23 12.47 -54 20 38.8 19.0 2.95853 1 23 11.76 -54 20 41.0 19.0 Twelve stacked 60-s CCD exposures taken remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) using a 0.51-m f/6.8 astrograph located at Siding Spring, NSW, Australia, on Oct. 3.44 UT show only a stellar appearance; the magnitude was 18.9 as measured within a circular aperture of radius 4".3. Images taken by A. Hale (Cloudcroft, NM, USA) on Oct. 19.2 using a 0.35-m f/3 Cassegrain reflector at Cerro Tololo show an essentially stellar object that was "possibly slightly diffuse in comparison to stars of similar brightness". J. Camarasa reported to the MPC that the object showed a very diffuse 11" coma on images taken on Oct. 25.9 with a 0.36-m f/8 reflector at the Skygems Namibia Remote Observatory. The available astrometry appears on MPEC 2024-V97. The following parabolic orbital elements by S. Nakano (Central Bureau) are from 108 observations spanning 2024 Oct. 2-Nov. 6 (mean residual 0".3). There are no close approaches to any major planets. T = 2027 May 7.35627 TT Peri. = 352.39091 Node = 100.69958 2000.0 q = 3.8483325 AU Incl. = 52.38941 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 6.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2024 10 17 01 15.77 -54 35.9 7.859 8.346 116.1 6.2 18.3 2024 10 27 01 10.50 -54 31.8 7.865 8.284 111.7 6.4 18.3 2024 11 06 01 05.64 -54 15.2 7.884 8.223 106.7 6.6 18.3 2024 11 16 01 01.50 -53 46.8 7.911 8.161 101.2 6.8 18.3 2024 11 26 00 58.29 -53 07.7 7.946 8.099 95.4 7.0 18.3 2024 12 06 00 56.20 -52 19.3 7.984 8.037 89.5 7.0 18.3 2024 12 16 00 55.31 -51 23.3 8.024 7.975 83.6 7.0 18.2 2024 12 26 00 55.63 -50 21.4 8.063 7.913 77.8 7.0 18.2 2025 01 05 00 57.13 -49 15.3 8.097 7.851 72.1 6.8 18.2 2025 01 15 00 59.74 -48 06.6 8.125 7.789 66.7 6.7 18.2 2025 01 25 01 03.36 -46 56.6 8.145 7.727 61.7 6.4 18.2 2025 02 04 01 07.90 -45 46.8 8.154 7.665 57.2 6.2 18.1 2025 02 14 01 13.23 -44 38.1 8.151 7.603 53.3 6.0 18.1 2025 02 24 01 19.27 -43 31.7 8.136 7.541 50.2 5.8 18.1 2025 03 06 01 25.89 -42 28.4 8.106 7.479 48.0 5.7 18.0 2025 03 16 01 33.01 -41 29.1 8.063 7.417 46.7 5.6 18.0 2025 03 26 01 40.52 -40 34.4 8.006 7.355 46.5 5.6 17.9 2025 04 05 01 48.35 -39 45.2 7.934 7.293 47.3 5.8 17.9 2025 04 15 01 56.41 -39 01.9 7.850 7.231 49.0 6.0 17.8 2025 04 25 02 04.62 -38 25.1 7.752 7.169 51.5 6.3 17.8 2025 05 05 02 12.90 -37 55.4 7.642 7.107 54.7 6.6 17.7 2025 05 15 02 21.17 -37 33.2 7.522 7.046 58.4 7.0 17.7 2025 05 25 02 29.35 -37 18.9 7.393 6.984 62.6 7.4 17.6 2025 06 04 02 37.36 -37 12.9 7.255 6.922 67.0 7.8 17.5 2025 06 14 02 45.09 -37 15.3 7.111 6.861 71.7 8.1 17.5 2025 06 24 02 52.47 -37 26.4 6.962 6.799 76.6 8.4 17.4 2025 07 04 02 59.38 -37 46.0 6.811 6.738 81.6 8.6 17.3 2025 07 14 03 05.70 -38 14.0 6.658 6.676 86.6 8.7 17.2 2025 07 24 03 11.32 -38 49.9 6.507 6.615 91.7 8.8 17.1 2025 08 03 03 16.10 -39 33.0 6.359 6.554 96.6 8.8 17.0 2025 08 13 03 19.90 -40 22.2 6.216 6.493 101.4 8.8 17.0 2025 08 23 03 22.60 -41 16.0 6.080 6.432 106.0 8.7 16.9 2025 09 02 03 24.05 -42 12.4 5.953 6.372 110.2 8.5 16.8 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2024 CBAT 2024 November 7 (CBET 5472) Daniel W. E. Green