Electronic Telegram No. 5639 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 V2 (RANKIN) David Rankin, Lunar and Planetary Laboratory, University of Arizona, reports his discovery of another comet on CCD images obtained with the 1.5-m Mt. Lemmon reflector on Nov. 2 (discovery observations tabulated below). Four 3-s exposures show a very condensed head of size 5" with no tail. 2025 UT R.A. (2000) Decl. Mag. Observer Nov. 2.47358 9 39 25.70 +10 39 12.0 19.8 Rankin 2.47980 9 39 25.84 +10 39 11.4 19.8 " 2.48601 9 39 26.01 +10 39 10.9 19.7 " R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reports that, after Rankin found pre-discovery Mt. Lemmon images from 2025 Jan. 27 (at mag 21.6-21.8), he searched for possible additional Pan-STARRS images of this comet. Four 45-s w-band stacked survey images taken on 2024 Dec. 4.54-4.59 UT with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala show no obvious coma (mag 21.4-22.8) and no obvious tail, but the head showed a size of about 2".0 (full-width-at-half-maximum) in 1".4-1".6 seeing. Likewise, Pan-STARRS1 images from 2025 Feb. 27.25-27.29 show no coma and no obvius tail, but four 45-s w-band survey images taken in 0".8-1".0 seeing show a head of size 1".1 (FWHM). Weryk also found the comet on Pan-STARRS1 images from 2024 Dec. 24.51-24.55 (mag 22.0-22.7), and 2025 Jan. 2.5 (mag 21.8-22.0), as well as Pan-STARRS2 images from 2024 Nov. 29.6 (mag 22.2-23.3), 2025 Dec. 29.52-29.56 (mag 22.0-22.4), and 2025 Jan. 21.4 (mag 21.7-22.3). Ten stacked 60-s CCD exposures taken remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) with a 0.51-m f/6.8 astrograph located at Rio Hurtado, Chile, on 2025 Nov. 19.34-19.35 UT show only a stellar appearance; the magnitude was 19.8 as measured within a circular aperture of radius 2".9. The available astrometry appears on MPEC 2025-W57. The following orbital elements by S. Nakano (Central Bureau) are from 69 observations spanning 2024 Nov. 29-2025 Nov. 19 (mean residual 0".4), with corresponding "original" and "future" values of 1/a being -0.000001 and -0.000086 (+/- 0.000023) AU**-1, respectively. The comet will pass 2.37 AU from Jupiter on 2026 Mar. 8 UT. Epoch = 2027 Mar. 16.0 TT T = 2027 Mar. 23.06832 TT Peri. = 102.80902 e = 0.9998791 Node = 138.08735 2000.0 q = 1.9497416 AU Incl. = 37.30667 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 10.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2025 10 12 09 29.02 +10 56.6 6.320 5.846 57.6 8.3 20.1 2025 10 22 09 34.23 +10 46.4 6.093 5.763 66.2 9.1 20.0 2025 11 01 09 38.81 +10 39.8 5.856 5.681 75.0 9.7 19.9 2025 11 11 09 42.65 +10 37.9 5.612 5.598 84.1 10.1 19.7 2025 11 21 09 45.62 +10 41.8 5.365 5.515 93.5 10.3 19.6 2025 12 01 09 47.58 +10 52.8 5.120 5.431 103.3 10.2 19.4 2025 12 11 09 48.42 +11 12.0 4.881 5.348 113.3 9.7 19.3 2025 12 21 09 48.04 +11 40.1 4.653 5.264 123.7 8.9 19.1 2025 12 31 09 46.37 +12 17.9 4.442 5.179 134.5 7.8 19.0 2026 01 10 09 43.42 +13 05.2 4.252 5.095 145.7 6.3 18.8 2026 01 20 09 39.26 +14 01.4 4.089 5.010 157.1 4.4 18.7 2026 01 30 09 34.07 +15 04.8 3.955 4.925 168.8 2.2 18.5 2026 02 09 09 28.17 +16 12.9 3.853 4.839 178.6 0.3 18.4 2026 02 19 09 21.93 +17 22.8 3.784 4.754 167.3 2.6 18.3 2026 03 01 09 15.82 +18 31.3 3.748 4.668 155.5 5.0 18.2 2026 03 11 09 10.29 +19 35.5 3.741 4.582 144.0 7.3 18.2 2026 03 21 09 05.76 +20 33.1 3.760 4.496 132.7 9.4 18.1 2026 03 31 09 02.57 +21 22.7 3.800 4.409 121.9 11.1 18.1 2026 04 10 09 00.92 +22 03.7 3.854 4.323 111.5 12.5 18.0 2026 04 20 09 00.94 +22 36.0 3.919 4.236 101.6 13.4 18.0 2026 04 30 09 02.64 +22 59.7 3.988 4.149 92.1 14.0 17.9 2026 05 10 09 05.97 +23 15.4 4.057 4.062 83.1 14.3 17.9 2026 05 20 09 10.86 +23 23.7 4.122 3.975 74.6 14.2 17.9 2026 05 30 09 17.18 +23 25.0 4.179 3.888 66.5 13.8 17.8 2026 06 09 09 24.82 +23 19.8 4.227 3.801 58.7 13.2 17.8 2026 06 19 09 33.67 +23 08.6 4.263 3.714 51.3 12.3 17.7 2026 06 29 09 43.61 +22 51.8 4.284 3.627 44.3 11.3 17.6 2026 11 16 13 28.89 +13 17.1 3.115 2.478 42.6 15.7 15.6 2026 11 26 13 51.09 +12 40.6 2.971 2.408 47.0 17.4 15.4 2026 12 06 14 14.22 +12 10.6 2.829 2.342 51.2 19.2 15.2 2026 12 16 14 38.24 +11 48.5 2.692 2.279 55.2 20.8 15.0 2026 12 26 15 03.09 +11 35.5 2.562 2.219 58.9 22.3 14.8 2027 01 05 15 28.66 +11 32.6 2.441 2.165 62.2 23.7 14.6 2027 01 15 15 54.74 +11 40.5 2.328 2.115 65.3 25.0 14.4 2027 01 25 16 21.10 +11 59.1 2.227 2.071 68.1 26.2 14.3 2027 02 04 16 47.43 +12 27.8 2.136 2.034 70.6 27.2 14.1 2027 02 14 17 13.40 +13 05.7 2.056 2.002 72.9 28.1 14.0 2027 02 24 17 38.62 +13 50.5 1.984 1.978 75.2 28.9 13.9 2027 03 06 18 02.74 +14 40.2 1.921 1.961 77.4 29.6 13.8 2027 03 16 18 25.40 +15 32.0 1.864 1.952 79.9 30.1 13.7 2027 03 26 18 46.29 +16 22.8 1.810 1.950 82.5 30.5 13.6 2027 04 05 19 05.13 +17 09.6 1.760 1.956 85.6 30.7 13.6 2027 04 15 19 21.63 +17 49.2 1.710 1.970 89.2 30.6 13.5 2027 04 25 19 35.58 +18 17.4 1.660 1.991 93.4 30.3 13.5 2027 05 05 19 46.77 +18 30.5 1.610 2.020 98.3 29.6 13.5 2027 05 15 19 55.01 +18 23.4 1.561 2.055 104.0 28.5 13.5 2027 05 25 20 00.21 +17 50.6 1.514 2.096 110.6 26.9 13.5 2027 06 04 20 02.34 +16 46.7 1.472 2.144 118.0 24.7 13.5 2027 06 14 20 01.58 +15 06.3 1.438 2.196 126.1 21.9 13.5 2027 06 24 19 58.36 +12 46.4 1.418 2.253 134.9 18.6 13.6 2027 07 04 19 53.35 +09 48.3 1.416 2.315 143.7 15.1 13.7 2027 07 14 19 47.43 +06 18.6 1.436 2.380 151.6 11.7 13.8 2027 07 24 19 41.60 +02 29.6 1.484 2.449 156.4 9.6 14.0 2027 08 03 19 36.72 -01 23.7 1.561 2.520 155.7 9.5 14.2 2027 08 13 19 33.48 -05 07.0 1.666 2.595 150.1 11.2 14.4 2027 08 23 19 32.26 -08 30.0 1.799 2.671 142.1 13.4 14.7 2027 09 02 19 33.17 -11 27.1 1.956 2.749 133.4 15.5 15.0 2027 09 12 19 36.18 -13 56.6 2.134 2.829 124.5 17.0 15.3 2027 09 22 19 41.10 -15 59.4 2.329 2.910 115.8 18.1 15.5 2027 10 02 19 47.68 -17 37.9 2.537 2.993 107.4 18.6 15.8 2027 10 12 19 55.69 -18 54.8 2.755 3.076 99.2 18.7 16.1 2027 10 22 20 04.87 -19 52.7 2.979 3.161 91.2 18.4 16.4 2027 11 01 20 15.00 -20 34.3 3.206 3.246 83.4 17.7 16.6 2027 11 11 20 25.88 -21 01.8 3.434 3.331 75.7 16.7 16.9 2027 11 21 20 37.31 -21 17.2 3.658 3.417 68.2 15.6 17.1 2027 12 01 20 49.15 -21 22.3 3.878 3.504 60.8 14.2 17.3 2027 12 11 21 01.26 -21 18.8 4.089 3.590 53.4 12.7 17.5 2027 12 21 21 13.52 -21 08.0 4.290 3.677 46.1 11.1 17.7 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2025 CBAT 2025 November 19 (CBET 5639) Daniel W. E. Green