Electronic Telegram No. 5609 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/2025 O3 = P/2012 T2 (PANSTARRS) R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reported the discovery of a comet in images obtained on Aug. 17 with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala, when three 45-s w-band survey images taken in 1".4-1".6 seeing showed a condensed head of size 2".2 (full-width-at-half-maximum) with no tail; he added that the point-spread function appeared slightly elongated toward the northwest. Three stacked 60-s gri-band follow-up images were obtained by Weryk (and R. Wainscoat) with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea on Aug. 18.49 UT (queue observer J. Nagasako; queue coordinator H. Flewelling) taken in 1".0 seeing show a condensed head of size 1".5 (FWHM) and a broad tail 5" long spanning p.a. 280-320 degrees. This was identified at the Minor Planet Center on Aug. 18 as a recovery of comet P/2012 T2 (cf. CBET 3254) and removed from its PCCP webpage then, but the MPC did not issue the recovery announcement in August, and on Sept. 18, Weryk reported another new comet candidate on Pan-STARRS1 images (again posted to the PCCP) that again turned out to be P/2012 T2 (this time identified by T. Kobayashi, Oizumi, Gunma-ken, Japan); four stacked 45-s w-band survey images on Sept. 18 taken in 1".3-1".4 seeing show a diffuse coma of size 2".2 (FWHM) and a straight 3" tail toward p.a. 330 degrees. Both sets of Pan-STARRS1 recovery observations are tabulated below. 2025 UT R.A. (2000) Decl. Mag. Aug. 17.52904 23 06 20.00 -22 33 09.1 21.0 17.53947 23 06 19.71 -22 33 11.7 20.9 17.54992 23 06 19.43 -22 33 13.8 20.6 17.56037 23 06 19.13 -22 33 16.4 21.1 17.61316 23 06 17.71 -22 33 28.4 20.6 17.61381 23 06 17.72 -22 33 28.3 21.4 17.61446 23 06 17.65 -22 33 28.8 21.2 Sept.18.36586 22 50 39.32 -24 05 19.6 20.8 18.37754 22 50 38.96 -24 05 20.7 20.7 18.38923 22 50 38.60 -24 05 21.3 20.9 18.40091 22 50 38.29 -24 05 22.8 21.0 18.50667 22 50 35.14 -24 05 32.8 21.0 18.50732 22 50 35.11 -24 05 33.0 21.1 Pan-STARRS1 observations were also identified from July 24.54-24.57 UT (at mag 21.5-21.7) and aug. 17.53-17.61 (mag 20.6-21.4), as well as images of the comet obtained on Aug. 2.52-2.55 with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala (mag 21.3-21.5). The available astrometry appears on MPEC 2025-S121. Because of the short arc in 2012 (only 34 days), the residuals for the 2025 July 24 observations were +1.80 deg in R.A. and +0.76 deg in Decl. from the prediction in the ICQ Comet Handbooks for 2013 and 2025, with a corresponding correction of Delta(T) = -17.9 days. The following linked orbital elements by S. Nakano (Central Bureau) are from 74 observations spanning 2012 Dec. 10-2025 Sept. 19 (mean residual 0".5). The comet passed 3.41 AU from Saturn on 1999 Oct. 27 UT and 0.060 AU from Jupiter on 2001 May 18. Prior to the close Jupiter approach, this comet had orbital elements T = 1984 May 13, q = 4.91 AU, e = 0.28, Peri. = 15.3 deg, Node = 98.5 deg, i = 6.9 deg (equinox J2000.0), a = 6.84 AU, P = 17.9 years. Epoch = 2013 Mar. 9.0 TT T = 2013 Mar. 25.81236 TT Peri. = 307.69903 e = 0.1567736 Node = 73.78536 2000.0 q = 4.8282784 AU Incl. = 12.55822 a = 5.7259572 AU n = 0.07193362 P = 13.70 years Epoch = 2026 Nov. 16.0 TT T = 2026 Dec. 5.39059 TT Peri. = 308.77084 e = 0.1567662 Node = 73.72172 2000.0 q = 4.8014780 AU Incl. = 12.57060 a = 5.6941243 AU n = 0.07253768 P = 13.59 years Epoch = 2040 June 15.0 TT T = 2040 May 28.45406 TT Peri. = 308.21134 e = 0.1562083 Node = 73.59936 2000.0 q = 4.7689356 AU Incl. = 12.59209 a = 5.6517922 AU n = 0.07335417 P = 13.44 years Epoch = 2053 Oct. 25.0 TT T = 2053 Oct. 18.69887 TT Peri. = 307.21112 e = 0.1557029 Node = 73.42319 2000.0 q = 4.7742674 AU Incl. = 12.58606 a = 5.6547244 AU n = 0.07329712 P = 13.45 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 11.5 and 2.5n = 7.5 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2025 09 02 22 58.88 -23 26.9 4.022 5.001 164.2 3.2 19.8 2025 09 12 22 53.79 -23 53.2 4.038 4.993 159.4 4.1 19.8 2025 09 22 22 48.95 -24 10.4 4.081 4.985 151.2 5.6 19.8 2025 10 02 22 44.73 -24 17.4 4.151 4.977 141.9 7.1 19.8 2025 10 12 22 41.45 -24 13.8 4.243 4.969 132.3 8.5 19.9 2025 10 22 22 39.33 -23 59.9 4.354 4.962 122.6 9.7 19.9 2025 11 01 22 38.52 -23 36.6 4.481 4.954 113.0 10.6 20.0 2025 11 11 22 39.05 -23 04.8 4.618 4.947 103.7 11.2 20.0 2025 11 21 22 40.90 -22 25.8 4.763 4.940 94.6 11.5 20.1 2025 12 01 22 44.01 -21 40.4 4.909 4.933 85.6 11.5 20.2 2025 12 11 22 48.25 -20 49.9 5.054 4.927 77.0 11.2 20.2 2025 12 21 22 53.52 -19 55.0 5.195 4.920 68.5 10.7 20.3 2025 12 31 22 59.67 -18 56.6 5.327 4.913 60.2 10.0 20.3 2026 01 10 23 06.58 -17 55.4 5.448 4.907 52.2 9.1 20.4 2026 01 20 23 14.13 -16 52.0 5.556 4.901 44.4 8.1 20.4 2026 05 20 01 00.14 -04 59.2 5.464 4.841 47.7 8.9 20.3 2026 05 30 01 07.92 -04 20.5 5.347 4.837 55.0 9.9 20.3 2026 06 09 01 15.16 -03 47.5 5.218 4.834 62.5 10.7 20.2 2026 06 19 01 21.78 -03 20.6 5.079 4.830 70.2 11.4 20.2 2026 06 29 01 27.66 -03 00.3 4.934 4.827 78.1 11.9 20.1 2026 07 09 01 32.69 -02 46.8 4.784 4.824 86.2 12.1 20.0 2026 07 19 01 36.76 -02 40.5 4.633 4.821 94.5 12.1 20.0 2026 07 29 01 39.74 -02 41.5 4.485 4.818 103.1 11.8 19.9 2026 08 08 01 41.55 -02 49.5 4.342 4.816 112.1 11.3 19.8 2026 08 18 01 42.09 -03 04.1 4.209 4.813 121.3 10.3 19.7 2026 08 28 01 41.34 -03 24.5 4.090 4.811 130.8 9.1 19.7 2026 09 07 01 39.32 -03 49.3 3.988 4.810 140.5 7.7 19.6 2026 09 17 01 36.13 -04 16.7 3.909 4.808 150.2 6.0 19.6 2026 09 27 01 31.97 -04 44.3 3.855 4.806 159.3 4.2 19.5 2026 10 07 01 27.13 -05 09.8 3.829 4.805 165.9 2.9 19.5 2026 10 17 01 21.96 -05 30.6 3.833 4.804 165.4 3.0 19.5 2026 10 27 01 16.88 -05 44.4 3.866 4.803 158.3 4.4 19.5 2026 11 06 01 12.25 -05 49.6 3.927 4.802 148.8 6.1 19.6 2026 11 16 01 08.43 -05 45.4 4.014 4.802 138.8 7.8 19.6 2026 11 26 01 05.68 -05 31.3 4.123 4.802 128.7 9.2 19.7 2026 12 06 01 04.15 -05 07.9 4.250 4.801 118.7 10.4 19.8 2026 12 16 01 03.93 -04 35.9 4.391 4.802 108.9 11.2 19.8 2026 12 26 01 05.02 -03 56.2 4.541 4.802 99.5 11.7 19.9 2027 01 05 01 07.36 -03 10.1 4.696 4.802 90.3 11.8 20.0 2027 01 15 01 10.87 -02 18.6 4.852 4.803 81.3 11.7 20.0 2027 01 25 01 15.43 -01 22.8 5.004 4.804 72.7 11.3 20.1 2027 02 04 01 20.94 -00 23.7 5.150 4.805 64.3 10.6 20.2 2027 02 14 01 27.26 +00 37.7 5.287 4.806 56.1 9.8 20.2 2027 02 24 01 34.30 +01 40.6 5.411 4.808 48.1 8.8 20.3 2027 07 14 03 36.84 +13 41.9 5.345 4.850 56.0 10.0 20.3 2027 07 24 03 43.96 +14 08.5 5.218 4.854 63.7 10.8 20.2 2027 08 03 03 50.34 +14 31.2 5.083 4.859 71.6 11.4 20.2 2027 08 13 03 55.83 +14 49.9 4.940 4.863 79.8 11.8 20.1 2027 08 23 04 00.32 +15 04.9 4.794 4.868 88.2 12.0 20.1 2027 09 02 04 03.68 +15 16.2 4.646 4.873 97.0 11.9 20.0 2027 09 12 04 05.77 +15 24.2 4.502 4.879 106.1 11.4 19.9 2027 09 22 04 06.51 +15 29.1 4.365 4.884 115.7 10.7 19.9 2027 10 02 04 05.85 +15 31.1 4.239 4.890 125.6 9.6 19.8 2027 10 12 04 03.78 +15 30.7 4.130 4.896 135.8 8.2 19.8 2027 10 22 04 00.43 +15 28.5 4.041 4.901 146.5 6.4 19.7 2027 11 01 03 55.97 +15 24.8 3.977 4.908 157.3 4.5 19.7 2027 11 11 03 50.71 +15 20.7 3.940 4.914 168.2 2.4 19.7 2027 11 21 03 45.03 +15 17.1 3.935 4.920 175.5 0.9 19.7 2027 12 01 03 39.37 +15 14.9 3.960 4.927 167.3 2.5 19.7 2027 12 11 03 34.16 +15 15.3 4.016 4.934 156.3 4.6 19.7 2027 12 21 03 29.78 +15 19.2 4.100 4.940 145.3 6.5 19.8 2027 12 31 03 26.51 +15 27.3 4.209 4.948 134.4 8.2 19.8 2028 01 10 03 24.55 +15 40.0 4.339 4.955 123.9 9.5 19.9 2028 01 20 03 23.98 +15 57.3 4.485 4.962 113.6 10.5 20.0 2028 01 30 03 24.82 +16 19.0 4.642 4.970 103.8 11.1 20.1 2028 02 09 03 27.02 +16 44.6 4.806 4.977 94.3 11.4 20.1 2028 02 19 03 30.49 +17 13.6 4.971 4.985 85.1 11.4 20.2 2028 02 29 03 35.11 +17 45.1 5.135 4.993 76.2 11.1 20.3 2028 03 10 03 40.76 +18 18.6 5.294 5.001 67.6 10.6 20.4 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2025 CBAT 2025 September 20 (CBET 5609) Daniel W. E. Green