Electronic Telegram No. 5567 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/2025 L2 Alain Maury, San Pedro de Atacama, Chile, reports the discovery by Jean Marc Mari (Biot, France) and Florian Signoret (Valbonne, France) of a comet in survey images obtained by their team (which includes also G. Attard and D. Parrott) on June 2 with a Celestron 0.28-m Schmidt astrograph (+ zwo6200MM camera in the course of their MAPS project (acronym from the last names of the team members). The images are acquired automatically via thirty-six 30-s exposures of each field; team members then look at downloaded images of objects that are found via Tycho Tracker software. Maury measured a diffuse coma of size 6" (full-width-at-half-maximum), compared to stars of similar brightness (3".5 FWHM) with a broad tail 10" long in p.a. 240 degrees on the discovery images. The confirming image shows a "fuzziness" around the center with a fan-shaped short tail. The discovery-night astrometry from Maury is tabulated below (the first three from the 0.28-m RASA telescope, and the remaining observations from the 50-cm reflector at the same site). 2025 UT R.A. (2000) Decl. Mag. June 2.30725 22 17 51.90 -12 32 00.7 18.7 2.31351 22 17 51.92 -12 32 05.6 18.8 2.31975 22 17 52.05 -12 32 10.3 19.3 2.36749 22 17 52.89 -12 32 46.4 19.4 2.37289 22 17 53.00 -12 32 50.3 19.5 2.37829 22 17 53.10 -12 32 54.2 19.3 2.39388 22 17 53.28 -12 33 06.6 19.5 2.39928 22 17 53.42 -12 33 09.9 19.3 2.40464 22 17 53.47 -12 33 14.0 19.4 After the comet was posted to the MPC's PCCP webpage, H. Sato (Tokyo, Japan) obtained twenty 60-s stacked CCD exposures obtained remotely with a 0.51-m f/6.8 astrograph located at Rio Hurtado, Chile, on June 11.35 UT show a strongly condensed coma 7" in diameter with an 8"-long tail toward p.a. 260 degrees; the magnitude was 19.2 as measured within a circular aperture of radius 3".6. The available astrometry appears on MPEC 2025-L62. The following parabolic orbital elements by S. Nakano (Central Bureau) are from 58 observations spanning June 2-11 (mean residual 0".5). There are no close approaches to major planets. T = 2025 Dec. 20.06990 TT Peri. = 232.43960 Node = 135.00370 2000.0 q = 2.8397453 AU Incl. = 86.58973 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 11.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2025 05 05 22 04.45 -08 08.8 3.787 3.644 74.2 15.4 18.9 2025 05 15 22 10.17 -09 22.7 3.566 3.585 82.9 16.3 18.7 2025 05 25 22 14.88 -10 56.2 3.343 3.527 92.0 16.7 18.5 2025 06 04 22 18.35 -12 53.8 3.122 3.470 101.5 16.6 18.3 2025 06 14 22 20.31 -15 20.1 2.911 3.415 111.4 16.1 18.1 2025 06 24 22 20.45 -18 19.4 2.713 3.362 121.8 14.9 17.9 2025 07 04 22 18.41 -21 54.2 2.538 3.311 132.5 13.1 17.7 2025 07 14 22 13.83 -26 03.7 2.391 3.261 143.1 10.8 17.5 2025 07 24 22 06.39 -30 41.3 2.280 3.214 152.3 8.4 17.3 2025 08 03 21 55.90 -35 33.8 2.209 3.169 157.1 7.2 17.2 2025 08 13 21 42.54 -40 22.3 2.182 3.126 154.2 8.1 17.2 2025 08 23 21 26.93 -44 46.8 2.197 3.086 145.6 10.7 17.1 2025 09 02 21 10.25 -48 31.9 2.250 3.048 134.9 13.6 17.1 2025 09 12 20 54.09 -51 31.1 2.333 3.013 123.9 16.1 17.2 2025 09 22 20 40.01 -53 46.3 2.439 2.981 113.2 18.0 17.2 2025 10 02 20 29.30 -55 25.1 2.558 2.952 103.2 19.3 17.3 2025 10 12 20 22.68 -56 36.7 2.683 2.926 93.9 19.9 17.4 2025 10 22 20 20.36 -57 29.7 2.809 2.903 85.4 20.0 17.4 2025 11 01 20 22.28 -58 10.4 2.929 2.884 77.6 19.6 17.5 2025 11 11 20 28.14 -58 43.6 3.040 2.868 70.6 19.0 17.6 2025 11 21 20 37.66 -59 11.9 3.139 2.855 64.4 18.2 17.6 2025 12 01 20 50.55 -59 36.8 3.224 2.846 59.1 17.3 17.7 2025 12 11 21 06.55 -59 59.1 3.293 2.841 54.8 16.5 17.7 2025 12 21 21 25.49 -60 18.5 3.346 2.840 51.5 15.7 17.7 2025 12 31 21 47.20 -60 34.4 3.383 2.842 49.4 15.2 17.8 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2025 CBAT 2025 June 11 (CBET 5567) Daniel W. E. Green