Electronic Telegram No. 5504 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/2024 A5 = P/2019 Y3 (CATALINA) R. Weryk, Department of Physics and Astronomy, University of Western Ontario, reported the discovery of another comet in images obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala on Jan. 7, and after he posted the find to the Minor Planet Center's PCCP webpage, it was identified at the MPC as observations of comet P/2019 Y3 (cf. CBET 4711). Weryk found that three 45-s w-band survey images taken in 1".6-1".7 seeing show a condensed head of size 2".0 (full-width-at-half-maximum) with a 5"-long straight tail in p.a. 60 degrees. The accidental recovery observations are tabulated below. 2025 UT R.A. (2000) Decl. Mag. Jan. 7.21881 2 13 54.95 -29 25 34.9 19.5 7.23943 2 13 54.91 -29 25 04.7 19.6 7.24975 2 13 54.91 -29 24 49.3 19.4 As the MPC delayed in announcing the recovery, M. Jaeger reported an independent recovery of comet P/2019 Y3 on CMOS images obtained by E. Prosperi and himself on Jan. 29.8 UT with a 0.35-m f/4.2 reflector at Martinsberg, Oed, Austria; thirty 50-s exposures show a 12" coma of total mag 18.3 with a 20" tail in p.a. 276 degrees. CCD exposures taken remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) with a 0.51-m f/6.8 astrograph located at Siding Spring, NSW, Australia, on Jan. 29.5 show a moderately condensed coma 10" in diameter; the magnitude was 18.4 as measured within a circular aperture of radius 5".4. The available astrometry appears on MPEC 2025-C161. The residuals of the recovery observations on 2025 Jan. 29 were -0.33 deg in R.A. and +0.29 deg in Decl. from the prediction in NK 5032 (and the ICQ's 2025 Comet Handbook), with a correction of Delta(T) = +1.37 days. The following linked orbital elements by S. Nakano (Central Bureau) are from 194 observations spanning 2019 Nov. 1- 2025 Feb. 5 (mean residual 0".5). The comet will pass 0.34 AU from the earth on 2025 Mar. 18 and 0.33 AU from Jupiter on 2033 July 4 UT. The comet passed 0.072 AU from Venus in 1958 and 0.11 AU from Jupiter in 1926. Nakano was unable to find earlier observations of this comet in archival data. Epoch = 2004 June 4.0 TT T = 2004 May 20.99997 TT Peri. = 2.30673 e = 0.6965864 Node = 139.38714 2000.0 q = 0.9093341 AU Incl. = 24.66107 a = 2.9970121 AU n = 0.18996401 P = 5.19 years Epoch = 2009 July 28.0 TT T = 2009 July 28.46100 TT Peri. = 2.27583 e = 0.6961607 Node = 139.39161 2000.0 q = 0.9111222 AU Incl. = 24.64093 a = 2.9986979 AU n = 0.18980385 P = 5.19 years Epoch = 2014 Sept.20.0 TT T = 2014 Oct. 4.55340 TT Peri. = 2.24686 e = 0.6967445 Node = 139.40381 2000.0 q = 0.9085970 AU Incl. = 24.66722 a = 2.9961437 AU n = 0.19004661 P = 5.19 years Epoch = 2019 Dec. 23.0 TT T = 2019 Dec. 13.46014 TT Peri. = 2.26754 e = 0.6959101 Node = 139.38641 2000.0 q = 0.9120295 AU Incl. = 24.63618 a = 2.9992101 AU n = 0.18975523 P = 5.19 years Epoch = 2025 Feb. 14.0 TT T = 2025 Mar. 4.38936 TT Peri. = 2.54920 e = 0.6914175 Node = 139.31064 2000.0 q = 0.9310322 AU Incl. = 24.58301 a = 3.0171263 AU n = 0.18806754 P = 5.24 years Epoch = 2030 May 19.0 TT T = 2030 June 3.23271 TT Peri. = 2.62555 e = 0.6909989 Node = 139.27589 2000.0 q = 0.9328503 AU Incl. = 24.56668 a = 3.0189226 AU n = 0.18789971 P = 5.24 years Epoch = 2035 Aug. 21.0 TT T = 2035 Aug. 3.67956 TT Peri. = 5.66497 e = 0.7293003 Node = 136.50343 2000.0 q = 0.7946668 AU Incl. = 21.46307 a = 2.9356033 AU n = 0.19595576 P = 5.03 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 19.0 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2025 01 25 02 22.38 -20 19.2 0.614 1.085 82.0 63.9 18.3 2025 01 30 02 27.14 -16 58.7 0.582 1.051 79.7 67.3 18.0 2025 02 04 02 32.83 -13 11.9 0.549 1.020 77.6 70.7 17.8 2025 02 09 02 39.38 -08 53.8 0.515 0.993 75.6 74.3 17.5 2025 02 14 02 46.71 -03 58.6 0.481 0.970 73.7 77.8 17.3 2025 02 19 02 54.84 +01 40.7 0.448 0.952 72.1 81.3 17.0 2025 02 24 03 03.83 +08 11.1 0.417 0.939 70.8 84.4 16.8 2025 03 01 03 13.87 +15 37.3 0.389 0.932 70.0 86.9 16.6 2025 03 06 03 25.32 +23 59.2 0.367 0.931 69.8 88.5 16.5 2025 03 11 03 38.83 +33 08.2 0.351 0.936 70.4 88.9 16.4 2025 03 16 03 55.59 +42 43.8 0.343 0.947 72.0 87.8 16.4 2025 03 21 04 17.85 +52 15.8 0.344 0.963 74.5 85.4 16.5 2025 03 26 04 49.95 +61 08.0 0.352 0.984 77.6 82.0 16.7 2025 03 31 05 40.23 +68 40.5 0.368 1.010 81.1 77.8 16.9 2025 04 05 07 01.53 +74 01.0 0.389 1.039 84.7 73.4 17.1 2025 04 10 08 54.12 +76 03.7 0.416 1.073 88.2 69.0 17.4 2025 04 15 10 38.53 +74 41.7 0.446 1.109 91.6 64.7 17.7 2025 04 20 11 47.45 +71 22.4 0.479 1.148 94.7 60.7 18.0 2025 04 25 12 29.36 +67 21.5 0.515 1.189 97.5 57.0 18.3 2025 04 30 12 56.08 +63 12.2 0.554 1.231 100.1 53.7 18.6 2025 05 05 13 14.40 +59 06.6 0.594 1.275 102.4 50.6 18.9 2025 05 10 13 27.85 +55 08.7 0.637 1.320 104.3 47.8 19.2 2025 05 15 13 38.35 +51 19.9 0.682 1.366 106.0 45.3 19.5 2025 05 20 13 46.97 +47 40.3 0.730 1.413 107.3 43.2 19.8 2025 05 25 13 54.40 +44 09.7 0.781 1.460 108.2 41.2 20.1 2025 05 30 14 01.07 +40 47.8 0.834 1.507 108.9 39.5 20.4 2025 06 04 14 07.27 +37 34.7 0.890 1.554 109.2 38.1 20.7 2025 06 09 14 13.19 +34 30.3 0.950 1.602 109.1 36.8 20.9 2025 06 14 14 18.94 +31 34.5 1.012 1.649 108.8 35.7 21.2 2025 06 19 14 24.59 +28 47.2 1.078 1.696 108.2 34.7 21.5 2025 06 24 14 30.22 +26 08.0 1.146 1.743 107.3 33.8 21.7 2025 06 29 14 35.88 +23 36.8 1.218 1.790 106.1 33.1 22.0 2025 07 04 14 41.60 +21 13.3 1.292 1.836 104.7 32.4 22.2 2025 07 09 14 47.38 +18 57.4 1.370 1.883 103.2 31.7 22.4 2025 07 14 14 53.24 +16 48.7 1.449 1.929 101.5 31.1 22.7 2025 07 19 14 59.18 +14 47.0 1.532 1.974 99.6 30.5 22.9 2025 07 24 15 05.22 +12 51.8 1.617 2.019 97.5 29.9 23.1 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2025 CBAT 2025 February 12 (CBET 5504) Daniel W. E. Green