Electronic Telegram No. 5262 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/2014 OL_465 (PANSTARRS) An apparently asteroidal object discovered in 2014 July images obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala, Hawaii, and given the minor-planet designation 2014 OL_465 (discovery observations tabulated below; cf. MPS 1559396, published in Mar. 2022) has been found to show cometary appearance in 2023. 2014 UT R.A. (2000) Decl. Mag. July 25.43060 20 34 20.88 -21 23 44.1 21.5 25.45458 20 34 19.81 -21 23 43.1 21.6 25.46657 20 34 19.26 -21 23 42.4 21.5 27.37457 20 32 55.69 -21 22 13.7 21.4 27.38673 20 32 55.15 -21 22 13.3 21.5 27.39892 20 32 54.62 -21 22 13.0 21.7 27.41110 20 32 54.07 -21 22 11.9 21.7 30.38506 20 30 44.01 -21 19 43.8 21.7 30.39698 20 30 43.47 -21 19 43.2 21.7 30.40889 20 30 42.92 -21 19 42.6 21.7 30.42081 20 30 42.38 -21 19 42.0 21.7 N. Erasmus, South African Astronomical Observatory (SAAO), wrote on 2023 Feb. 20 that this object appears brighter (by perhaps 2 magnitudes) than expected for at least 6-7 weeks in CCD images obtained in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program, specifically mentioned images obtained with the 0.5-m f/2 Schmidt reflector at Rio Hurtado, Chile, on 2023 Feb. 1 and 3. Follow-up observations obtained on Feb. 3.0 and 5.0 with the SAAO 1-m Lesedi Telescope at Sutherland confirm the brightening and show a larger size for the object 3".6 (full-width-at-half-maximum) vs. 2".7 for nearby stars -- though stating that no clear coma or tail was visible. A. Fitzsimmons, Queen's University, Belfast, found no earlier ATLAS images showing the field of the comet between 2022 Dec. 2 and 2023 Jan. 12, while images from 2023 Jan. 13.5 UT show it to be stellar within the limits of seeing then (4".4 FWHM); on Jan. 22.5, the object showed a size of 6".1 (FWHM) in 4".2 seeing but no obvious coma. These January 2023 single-night ATLAS observations were reported as an unknown object and placed in the MPC's "isolated tracklet file". Fitzsimmons adds that they clearly imaged a diffuse coma of size 8".0 (FWHM) in 5".7 seeing, with an apparent tail seen as an extension to the coma in each of four 30-s images obtained on 2023 May 17.96 (with a coma and tail also noted by Fitzsimmons in Apr. 13 ATLAS images). Noting the listing of 2014 OL_465 on the Minor Planet Center's PCCP webpage, H. Sato (Bunkyo-ku, Tokyo, Japan) obtained twelve stacked 60-s CCD exposures on 2023 May 19.32 UT with a "Deep Sky Chile" 0.51-m f/6.8 astrograph located at Rio Hurtado, Chile, showing a strongly condensed, round coma 10" in diameter and no tail; the magnitude was 17.7 as measured within a circular aperture of radius 5".0. The available astrometry appears on MPEC 2023-K66 and includes pre- discovery Pan-STARRS1 observations from 2012 Mar. 21.3 UT that were published on MPS 1740967 (Feb. 2023) with magnitude 21.3-21.4. The following linked orbital elements by S. Nakano (Central Bureau) are from 82 observations spanning 2012-2023 (mean residual 0".4). The comet passed 0.78 AU from Jupiter in 1931 May. No other observations were found in an archival search. Epoch = 2002 Nov. 22.0 TT T = 2002 Nov. 23.10436 TT Peri. = 267.51719 e = 0.2818982 Node = 309.80854 2000.0 q = 3.3458320 AU Incl. = 21.70667 a = 4.6592723 AU n = 0.09800019 P = 10.056 years Epoch = 2012 Dec. 19.0 TT T = 2012 Dec. 29.13025 TT Peri. = 267.52913 e = 0.2811155 Node = 309.73434 2000.0 q = 3.3685450 AU Incl. = 21.66903 a = 4.6857947 AU n = 0.09716933 P = 10.14 years Epoch = 2023 Feb. 25.0 TT T = 2023 Feb. 28.23180 TT Peri. = 267.70558 e = 0.2807524 Node = 309.59561 2000.0 q = 3.3725326 AU Incl. = 21.66341 a = 4.6889733 AU n = 0.09707054 P = 10.15 years Epoch = 2033 May 3.0 TT T = 2033 Apr. 15.81870 TT Peri. = 268.03621 e = 0.2820351 Node = 309.41002 2000.0 q = 3.3492309 AU Incl. = 21.69133 a = 4.6648952 AU n = 0.09782306 P = 10.08 years Epoch = 2043 Apr. 21.0 TT T = 2043 Apr. 28.24500 TT Peri. = 268.02605 e = 0.2837252 Node = 309.39671 2000.0 q = 3.3291336 AU Incl. = 21.71270 a = 4.6478442 AU n = 0.09836186 P = 10.02 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 11.0 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2023 05 16 14 29.21 -46 11.0 2.480 3.394 150.1 8.5 18.3 2023 05 26 14 22.50 -45 13.7 2.503 3.400 147.4 9.2 18.3 2023 06 05 14 17.68 -44 04.1 2.549 3.406 142.1 10.5 18.4 2023 06 15 14 15.14 -42 48.6 2.616 3.414 135.3 12.1 18.4 2023 06 25 14 15.04 -41 32.9 2.703 3.422 127.8 13.6 18.5 2023 07 05 14 17.31 -40 22.0 2.806 3.430 120.1 14.9 18.6 2023 07 15 14 21.76 -39 18.6 2.922 3.439 112.3 15.9 18.7 2023 07 25 14 28.17 -38 24.6 3.049 3.449 104.7 16.6 18.8 2023 08 04 14 36.31 -37 40.4 3.184 3.460 97.2 16.9 18.9 2023 08 14 14 45.95 -37 05.5 3.322 3.471 89.8 17.0 19.0 2023 08 24 14 56.89 -36 39.0 3.464 3.483 82.7 16.7 19.1 2023 09 03 15 08.94 -36 19.8 3.604 3.495 75.7 16.2 19.2 2023 09 13 15 21.95 -36 06.4 3.743 3.508 68.9 15.5 19.3 2023 09 23 15 35.79 -35 57.4 3.877 3.521 62.1 14.6 19.4 2023 10 03 15 50.33 -35 51.3 4.005 3.535 55.5 13.5 19.5 2023 10 13 16 05.46 -35 46.9 4.125 3.550 48.9 12.2 19.6 2023 10 23 16 21.07 -35 43.0 4.235 3.565 42.5 10.9 19.7 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 May 20 (CBET 5262) Daniel W. E. Green