Electronic Telegram No. 5340 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/2023 WM_26 = P/2011 NO_1 (ELENIN) [Editor's note: this replaces CBET 5339 (orbital elements).] An apparently asteroidal object discovered on images obtained on 2023 Nov. 18 with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala (and given the minor-planet designation 2023 WM_26 when announced on MPEC 2023-Y72) has been found to be an accidental recovery of comet P/2011 NO_1 (cf. IAUC 9227; CBET 2768); the Pan-STARRS2 observations are tabulated below, together with other apparently asteroidal Pan-STARRS2 observations from 2023 Nov. 12 that were found later, and additional apparently asteroidal observations that were made in 2023 October with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala. 2023 UT R.A. (2000) Decl. Mag. Oct. 17.59024 8 07 22.98 +25 41 10.0 22.4 17.60242 8 07 23.86 +25 41 06.0 23.3 24.60578 8 15 41.88 +25 04 34.8 22.5 24.61421 8 15 42.44 +25 04 32.2 22.7 24.62265 8 15 43.01 +25 04 29.5 22.4 Nov. 12.57442 8 35 34.26 +23 15 38.8 22.0 12.58555 8 35 34.87 +23 15 34.0 22.0 12.59670 8 35 35.48 +23 15 30.2 21.5 18.56288 8 40 49.18 +22 38 16.2 21.7 18.57518 8 40 49.77 +22 38 11.6 21.9 18.58762 8 40 50.36 +22 38 06.9 21.8 M. Meyer reported the suggested identification of 2023 WM_26 with comet P/2011 NO_1 on 2023 Dec. 21. H. Sato (Bunkyo-ku, Tokyo, Japan) wrote a couple of days later that eight stacked 120-s CCD exposures taken remotely by Sato with a 0.51-m f/6.8 astrograph on 2023 Dec. 23.3 UT show a strongly condensed coma 5" in diameter with no tail; the magnitude was 19.9 as measured within a circular aperture of radius 2".8. Additional astrometry appears on MPEC 2024-B143. The residuals for the 2023 October observations are +212" in R.A. and -80" in Decl. from the prediction in NK 4403 (and the ICQ's 2023 Comet Handbook), and the residuals for the 2023 Nov. 18 observations are +318" and -149", respectively, corresponding to a correction of Delta(T) = -0.25 day. The following linked orbital elements by S. Nakano (Central Bureau) are from 167 observations spanning 2011 June 12-2024 Jan. 22 (mean residual 0".5). There are no close approaches to major planets. Epoch = 2011 Feb. 8.0 TT T = 2011 Jan. 20.10269 TT Peri. = 263.42273 e = 0.7791500 Node = 296.11828 2000.0 q = 1.2409583 AU Incl. = 15.40136 a = 5.6190086 AU n = 0.07399707 P = 13.32 years Epoch = 2024 May 10.0 TT T = 2024 May 5.24387 TT Peri. = 263.52566 e = 0.7788324 Node = 295.83318 2000.0 q = 1.2437023 AU Incl. = 15.39788 a = 5.6233483 AU n = 0.07391143 P = 13.34 years Epoch = 2037 Sept.19.0 TT T = 2037 Sept.13.28238 TT Peri. = 265.61587 e = 0.7776556 Node = 293.74322 2000.0 q = 1.2481066 AU Incl. = 15.74349 a = 5.6133928 AU n = 0.07410814 P = 13.30 years Epoch = 2051 Jan. 29.0 TT T = 2051 Jan. 19.87436 TT Peri. = 265.66745 e = 0.7762539 Node = 293.38467 2000.0 q = 1.2694254 AU Incl. = 15.72704 a = 5.6735075 AU n = 0.07293343 P = 13.51 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 13.5 and 2.5n = 15 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2024 01 11 08 48.51 +15 26.2 0.977 1.929 159.5 10.3 17.7 2024 01 16 08 44.19 +14 29.4 0.917 1.885 165.0 7.7 17.4 2024 01 21 08 38.94 +13 27.9 0.864 1.841 170.2 5.2 17.2 2024 01 26 08 32.87 +12 21.5 0.816 1.798 173.4 3.6 16.9 2024 01 31 08 26.15 +11 10.1 0.775 1.755 171.2 4.9 16.6 2024 02 05 08 18.99 +09 54.1 0.740 1.713 165.8 8.1 16.4 2024 02 10 08 11.68 +08 34.1 0.711 1.672 159.6 11.9 16.1 2024 02 15 08 04.53 +07 11.0 0.688 1.631 153.2 15.8 15.9 2024 02 20 07 57.88 +05 45.7 0.669 1.592 146.8 19.9 15.7 2024 02 25 07 52.02 +04 19.4 0.656 1.553 140.6 23.8 15.5 2024 03 01 07 47.20 +02 52.9 0.646 1.516 134.7 27.7 15.3 2024 03 06 07 43.63 +01 26.9 0.639 1.481 129.1 31.3 15.1 2024 03 11 07 41.46 +00 01.9 0.634 1.447 123.9 34.7 14.9 2024 03 16 07 40.79 -01 22.4 0.631 1.415 119.2 37.9 14.8 2024 03 21 07 41.68 -02 46.2 0.630 1.385 114.9 40.7 14.6 2024 03 26 07 44.12 -04 10.0 0.628 1.357 111.1 43.3 14.5 2024 03 31 07 48.10 -05 34.3 0.628 1.332 107.7 45.6 14.4 2024 04 05 07 53.60 -06 59.6 0.627 1.309 104.8 47.6 14.2 2024 04 10 08 00.61 -08 26.4 0.626 1.290 102.4 49.3 14.1 2024 04 15 08 09.14 -09 55.3 0.625 1.274 100.4 50.8 14.1 2024 04 20 08 19.15 -11 26.6 0.623 1.261 98.8 51.9 14.0 2024 04 25 08 30.65 -13 00.3 0.622 1.251 97.7 52.8 13.9 2024 04 30 08 43.62 -14 36.1 0.621 1.246 97.0 53.4 13.9 2024 05 05 08 58.09 -16 13.4 0.620 1.244 96.6 53.7 13.9 2024 05 10 09 14.08 -17 51.3 0.621 1.245 96.7 53.6 13.9 2024 05 15 09 31.56 -19 28.8 0.623 1.251 97.0 53.3 13.9 2024 05 20 09 50.47 -21 04.3 0.628 1.260 97.7 52.8 14.0 2024 05 25 10 10.73 -22 35.7 0.634 1.272 98.5 51.9 14.1 2024 05 30 10 32.18 -24 00.8 0.644 1.288 99.5 50.9 14.2 2024 06 04 10 54.61 -25 17.7 0.658 1.307 100.7 49.7 14.3 2024 06 09 11 17.79 -26 24.6 0.676 1.329 101.8 48.4 14.5 2024 06 14 11 41.38 -27 20.5 0.698 1.354 102.8 47.0 14.7 2024 06 19 12 05.05 -28 04.7 0.726 1.382 103.7 45.6 14.9 2024 06 24 12 28.48 -28 37.4 0.758 1.411 104.5 44.2 15.1 2024 06 29 12 51.38 -28 59.0 0.795 1.443 104.9 42.9 15.4 2024 07 04 13 13.54 -29 11.1 0.838 1.477 105.2 41.6 15.7 2024 07 09 13 34.80 -29 15.1 0.886 1.513 105.1 40.5 15.9 2024 07 14 13 55.09 -29 12.6 0.938 1.549 104.8 39.4 16.2 2024 07 19 14 14.36 -29 05.2 0.996 1.588 104.2 38.4 16.5 2024 07 24 14 32.61 -28 54.0 1.058 1.627 103.4 37.4 16.8 2024 07 29 14 49.88 -28 40.2 1.124 1.668 102.3 36.5 17.1 2024 08 03 15 06.25 -28 24.6 1.195 1.709 101.0 35.7 17.4 2024 08 08 15 21.80 -28 07.9 1.269 1.751 99.6 34.8 17.7 2024 08 13 15 36.59 -27 50.5 1.347 1.794 98.0 34.0 18.0 2024 08 18 15 50.70 -27 32.9 1.428 1.837 96.2 33.2 18.2 2024 08 23 16 04.20 -27 15.0 1.512 1.880 94.3 32.4 18.5 2024 08 28 16 17.14 -26 57.1 1.599 1.925 92.3 31.6 18.8 2024 09 02 16 29.60 -26 39.1 1.688 1.969 90.2 30.8 19.1 2024 09 07 16 41.63 -26 21.2 1.780 2.013 87.9 30.0 19.3 2024 09 12 16 53.27 -26 03.1 1.873 2.058 85.6 29.2 19.6 2024 09 17 17 04.57 -25 44.9 1.969 2.103 83.3 28.3 19.8 2024 09 22 17 15.54 -25 26.4 2.066 2.148 80.8 27.5 20.1 2024 09 27 17 26.24 -25 07.6 2.164 2.193 78.3 26.6 20.3 2024 10 02 17 36.67 -24 48.5 2.263 2.238 75.8 25.7 20.5 2024 10 07 17 46.88 -24 28.8 2.363 2.283 73.1 24.8 20.7 2024 10 12 17 56.87 -24 08.6 2.463 2.328 70.5 23.8 21.0 2024 10 17 18 06.65 -23 47.7 2.564 2.373 67.8 22.9 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 January 28 (CBET 5340) Daniel W. E. Green