Electronic Telegram No. 5436 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 O3 = P/2010 WK = P/2010 PB_57 (LINEAR) An apparently asteroidal object discovered in a survey called the "Zwicky Transient Facility" (ZTF), in CCD images taken using the 1.2-m Schmidt telescope at Palomar (discovery observations tabulated below), has been identified (apparently by A. Odasso on the MPML forum) with comet P/2010 WK (cf. CBET 2607; IAUC 9195). 2024 UT R.A. (2000) Decl. Mag. July 18.47582 4 45 25.47 +27 48 07.0 19.9 18.47891 4 45 26.04 +27 48 08.4 19.6 18.48216 4 45 26.65 +27 48 10.7 19.6 27.47781 5 12 09.82 +29 04 54.2 19.5 27.48256 5 12 10.71 +29 04 56.6 19.3 28.48003 5 15 09.13 +29 12 24.9 19.3 28.48291 5 15 09.63 +29 12 25.7 19.1 28.48688 5 15 10.34 +29 12 27.4 19.1 Aug. 3.48335 5 33 03.59 +29 52 57.1 18.7 3.48572 5 33 03.96 +29 52 57.8 19.0 3.48960 5 33 04.73 +29 52 59.8 19.0 Following a request by the Central Bureau, Q.-z. Ye (University of Maryland) reports that the July 28 images do show a 5" coma in 2".3 seeing; he adds that the morphology of the comet appears similar on the other three nights. MPEC MPEC 2024-Q34 contains additional astrometry. The residuals for the recovery observations were +13'.1 in R.A. and +3'.4 in Decl. from the prediction in NK 2089 (= ICQ's Comet Handbook 2024), with a corresponding correction of Delta(T) = -0.60 day. The identification 2010 WK = 2010 PB_57 was found by S. Nakano, Sumoto, Japan (NK 2028). The following linked orbital elements by Nakano are from 609 observations spanning 2010 Aug. 10-2024 Aug. 13 (mean residual 0".6). These show that the comet passed 0.27 AU from Jupiter in 1945 July; it will pass 1.01 AU from Jupiter on 2040 Apr. 12, and 1.64 AU from Saturn on 2042 Oct. 2 UT. Epoch = 1997 Apr. 22.0 TT T = 1997 May 8.16046 TT Peri. = 40.33715 e = 0.6931144 Node = 12.77030 2000.0 q = 1.7305153 AU Incl. = 11.55439 a = 5.6389598 AU n = 0.07360471 P = 13.39 years Epoch = 2010 Oct. 11.0 TT T = 2010 Oct. 19.74630 TT Peri. = 40.84512 e = 0.6920433 Node = 11.48808 2000.0 q = 1.7651334 AU Incl. = 11.47903 a = 5.7317581 AU n = 0.07182445 P = 13.72 years Epoch = 2024 July 29.0 TT T = 2024 July 20.53706 TT Peri. = 41.00330 e = 0.6909464 Node = 11.32401 2000.0 q = 1.7822695 AU Incl. = 11.40066 a = 5.7668617 AU n = 0.07116964 P = 13.85 years Epoch = 2038 Apr. 7.0 TT T = 2038 Apr. 10.62630 TT Peri. = 40.91242 e = 0.6912713 Node = 11.25601 2000.0 q = 1.7660277 AU Incl. = 11.39687 a = 5.7203217 AU n = 0.07203995 P = 13.68 years Epoch = 2051 July 8.0 TT T = 2051 June 29.86467 TT Peri. = 40.78838 e = 0.6925849 Node = 9.58915 2000.0 q = 1.7159579 AU Incl. = 11.11009 a = 5.5818924 AU n = 0.07473635 P = 13.19 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 14.5 and 2.5n = 10 for the magnitudes. This comet exhibited an unusual light curve in 2010-2011, and at the same distance just past perihelion, the comet now appears to be roughly 3 magnitudes fainter in absolute brightness than at the discovery apparition. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2024 07 29 05 16.70 +29 16.2 2.336 1.785 45.9 24.1 18.9 2024 08 08 05 46.50 +30 18.5 2.289 1.793 48.9 25.2 18.8 2024 08 18 06 15.96 +30 59.9 2.243 1.808 52.2 26.2 18.8 2024 08 28 06 44.70 +31 22.0 2.198 1.829 55.6 27.1 18.8 2024 09 07 07 12.34 +31 26.9 2.153 1.856 59.4 27.9 18.9 2024 09 17 07 38.50 +31 17.9 2.108 1.888 63.5 28.5 18.9 2024 09 27 08 02.90 +30 58.7 2.061 1.925 68.0 28.9 18.9 2024 10 07 08 25.29 +30 33.6 2.012 1.966 72.9 29.1 19.0 2024 10 17 08 45.43 +30 06.6 1.961 2.012 78.3 29.0 19.0 2024 10 27 09 03.13 +29 41.7 1.907 2.061 84.3 28.7 19.0 2024 11 06 09 18.17 +29 23.0 1.852 2.113 90.8 28.0 19.1 2024 11 16 09 30.30 +29 13.5 1.797 2.168 98.0 26.8 19.1 2024 11 26 09 39.29 +29 15.6 1.743 2.226 105.9 25.2 19.2 2024 12 06 09 44.85 +29 30.7 1.693 2.286 114.6 23.1 19.2 2024 12 16 09 46.80 +29 57.9 1.652 2.348 123.9 20.4 19.3 2024 12 26 09 45.07 +30 34.2 1.622 2.411 133.9 17.1 19.4 2025 01 05 09 39.86 +31 14.3 1.610 2.475 144.2 13.4 19.5 2025 01 15 09 31.79 +31 50.4 1.618 2.541 154.3 9.7 19.6 2025 01 25 09 21.90 +32 15.3 1.652 2.607 162.2 6.6 19.8 2025 02 04 09 11.49 +32 23.4 1.713 2.674 163.9 5.9 19.9 2025 02 14 09 01.94 +32 12.7 1.801 2.741 158.0 7.8 20.2 2025 02 24 08 54.28 +31 44.8 1.915 2.809 148.9 10.5 20.4 2025 03 06 08 49.11 +31 03.0 2.053 2.878 139.2 13.0 20.7 2025 03 16 08 46.64 +30 11.2 2.210 2.946 129.6 15.1 20.9 2025 03 26 08 46.74 +29 12.8 2.384 3.014 120.4 16.6 21.2 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2024 CBAT 2024 August 26 (CBET 5436) Daniel W. E. Green