Electronic Telegram No. 5137 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/2022 C4 = P/2010 LK_36 = P/2016 MD = P/2016 PM_1 (WISE-PANSTARRS) An apparently asteroidal object with three separate minor-planet designations has been found to show cometary activity at its current return to perihelion. It was detected by the Wide-field Infrared Survey Explorer (WISE) spacecraft on 2010 June 9, whence it was given the designation 2010 LK_36 (cf. MPS 332284; discovery observations tabulated below, in which the listed optical-wavelength magnitude was roughly estimated based on previous WISE cometary observations). It was again found with the renamed Near-Earth Object Wide-field Infrared Survey Explorer (or NEOWISE; formerly the WISE earth-orbiting satellite; cf. CBET 4225) on 2016 June 16, but not identified with the two-day 2010 arc at that time and given the new minor-planet designation 2016 MD (cf. MPS 716660). 2010 UT R.A. (2000) Decl. Mag. June 9.12001 23 51 06.34 -24 36 06.5 9.51692 23 51 57.74 -24 39 06.1 9.64922 23 52 14.83 -24 40 06.3 9.78153 23 52 31.92 -24 41 06.2 9.84774 23 52 40.45 -24 41 37.0 9.91383 23 52 48.97 -24 42 07.2 9.98005 23 52 57.48 -24 42 37.5 10.04613 23 53 05.99 -24 43 07.8 10.04626 23 53 06.00 -24 43 07.5 10.11235 23 53 14.55 -24 43 38.6 10.50926 23 54 05.42 -24 46 40.7 10.64157 23 54 22.32 -24 47 42.5 10.77387 23 54 39.23 -24 48 44.2 11.03848 23 55 12.96 -24 50 47.3 2016 UT R.A. (2000) Decl. Mag. June 16.86411 0 23 17.53 -20 41 25.8 20 16.99515 0 23 31.07 -20 42 03.5 17.12618 0 23 44.58 -20 42 38.3 17.19163 0 23 51.40 -20 42 56.0 17.19175 0 23 51.39 -20 42 56.8 17.51927 0 24 24.90 -20 44 25.6 17.58485 0 24 31.76 -20 44 46.4 17.65030 0 24 38.43 -20 45 04.5 17.71588 0 24 45.16 -20 45 22.8 17.97794 0 25 11.86 -20 46 36.5 18.24000 0 25 38.54 -20 47 52.1 It was rediscovered on 2016 Aug. 1 in images obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala, Hawaii, and designated 2016 PM_1, after which the earlier WISE/NEOWISE observations were connected with that later Pan-STARRS1 detection. The Pan-STARRS1 discovery observations are tabulated below (cf. MPS 722200). 2016 UT R.A. (2000) Decl. Mag. Aug. 1.58311 1 11 04.03 -27 20 09.2 20.6 1.59168 1 11 04.14 -27 20 15.5 20.6 1.60024 1 11 04.25 -27 20 21.7 20.7 1.60879 1 11 04.34 -27 20 28.8 20.8 Earlier observations were subsequently identified in Sloan Digital Sky Survey images obtained at Apache Point in 2003 (observations tabulated below; cf. MPS 867658). 2003 UT R.A. (2000) Decl. Mag. Apr. 26.26209 12 23 18.10 +40 59 59.2 21.2 26.26556 12 23 17.91 +40 59 57.9 22.1 P. Veres, Minor Planet Center, writes that A. Fitzsimmons (Queen's University, Belfast) has found this object to show cometary appearance on CCD images taken on 2022 June 6.33-6.40 UT with a 0.5-m f/2 Schmidt reflector at Mauna Loa, Hawaii, in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program, when Fitzsimmons noted that the object's image appears soft, and that four individual exposures show a size of 6".1 (full-width-at-half-maximum) in 5".2 seeing with no tail and magnitude 17.2-17.6; when stacking the four exposures, he noticed a possible low- surface-brightness extension of length 9" in p.a. 120 degrees. Additional observations with the same telescope on June 8.35-8.40 show it to be definitely cometary in individual 30-s ATLAS exposures, with a compact coma extending to 13" from the condensation in p.a. 120 degrees but oddly stating that there was no tail; the size was 6".4 (FWHM) in 5".4 seeing (magnitude 17.2-17.5). Following a request by Veres, R. Weryk (Department of Physics and Astronomy, University of Western Ontario) found the object to be clearly cometary in images obtained on 2022 June 3.3 with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala, when four 45-s stacked w-band survey images showed a tail > 15" long toward p.a. 145 degrees; the best image showed a very condensed coma of size 1".4 (FWHM) in 1".2 seeing. The first astrometry available at the current apparition are those from 2022 Feb. 7 by Pan-STARRS2 (tabulated below), and it has been followed every month since then as it has gradually brightened to mag 19.3-19.9 in March, 18-19 in April, to mag 17.0-17.5 by late May and during June now (cf. MPEC 2022-M81). 2022 UT R.A. (2000) Decl. Mag. Feb. 7.54365 14 25 15.43 +17 29 32.3 20.7 7.55638 14 25 16.46 +17 29 36.5 20.6 7.56906 14 25 17.49 +17 29 41.0 20.6 7.58181 14 25 18.52 +17 29 45.3 20.6 The following linked orbital elements by S. Nakano (Central Bureau) are from 256 observations spanning 2003-2022 (mean residual 0".3), indicating that the comet passed 0.135 AU from Jupiter on 2013 July 31 UT. Epoch = 2003 Oct. 8.0 TT T = 2003 Oct. 19.98067 TT Peri. = 177.04018 e = 0.5353642 Node = 91.99047 2000.0 q = 1.6039128 AU Incl. = 26.59335 a = 3.4519788 AU n = 0.15367453 P = 6.41 years Epoch = 2010 Mar. 25.0 TT T = 2010 Mar. 20.50931 TT Peri. = 177.16663 e = 0.5358311 Node = 91.94124 2000.0 q = 1.6006969 AU Incl. = 26.60578 a = 3.4485224 AU n = 0.15390563 P = 6.40 years Epoch = 2016 Feb. 22.0 TT T = 2016 Mar. 1.83367 TT Peri. = 170.75508 e = 0.5702827 Node = 89.45686 2000.0 q = 1.4732341 AU Incl. = 22.12212 a = 3.4283802 AU n = 0.15526394 P = 6.35 years Epoch = 2022 June 30.0 TT T = 2022 July 10.38346 TT Peri. = 170.89612 e = 0.5702324 Node = 89.40485 2000.0 q = 1.4731473 AU Incl. = 22.12499 a = 3.4277764 AU n = 0.15530497 P = 6.35 years Epoch = 2028 Dec. 15.0 TT T = 2028 Dec. 22.38152 TT Peri. = 172.59272 e = 0.5518815 Node = 88.06722 2000.0 q = 1.5637540 AU Incl. = 22.57518 a = 3.4895992 AU n = 0.15119616 P = 6.52 years Epoch = 2035 July 12.0 TT T = 2035 July 6.38865 TT Peri. = 172.77777 e = 0.5509047 Node = 88.01008 2000.0 q = 1.5691612 AU Incl. = 22.55863 a = 3.4940496 AU n = 0.15090738 P = 6.53 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 16.0 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 05 21 14 41.32 +22 11.8 0.681 1.567 134.5 27.4 17.1 2022 05 26 14 37.39 +20 07.8 0.670 1.550 133.0 28.5 17.0 2022 05 31 14 34.14 +17 43.1 0.663 1.535 131.3 29.8 17.0 2022 06 05 14 31.77 +14 59.5 0.659 1.521 129.4 31.0 16.9 2022 06 10 14 30.40 +11 59.8 0.659 1.508 127.3 32.4 16.9 2022 06 15 14 30.11 +08 47.1 0.662 1.498 125.2 33.7 16.9 2022 06 20 14 30.93 +05 24.9 0.668 1.489 122.9 34.9 16.9 2022 06 25 14 32.88 +01 56.7 0.679 1.482 120.7 36.1 16.9 2022 06 30 14 35.97 -01 34.4 0.692 1.477 118.4 37.3 16.9 2022 07 05 14 40.18 -05 05.2 0.710 1.474 116.1 38.2 16.9 2022 07 10 14 45.48 -08 32.9 0.731 1.473 113.9 39.1 17.0 2022 07 15 14 51.83 -11 54.9 0.755 1.474 111.8 39.8 17.1 2022 07 20 14 59.18 -15 09.3 0.782 1.477 109.7 40.4 17.2 2022 07 25 15 07.50 -18 14.5 0.812 1.481 107.8 40.8 17.3 2022 07 30 15 16.77 -21 09.4 0.845 1.488 105.8 41.0 17.4 2022 08 04 15 26.95 -23 53.1 0.882 1.496 104.0 41.1 17.5 2022 08 09 15 37.98 -26 24.9 0.920 1.507 102.2 41.1 17.6 2022 08 14 15 49.83 -28 44.4 0.962 1.519 100.5 41.0 17.7 2022 08 19 16 02.43 -30 51.3 1.005 1.532 98.8 40.7 17.9 2022 08 24 16 15.74 -32 45.5 1.052 1.547 97.2 40.4 18.0 2022 08 29 16 29.71 -34 27.1 1.100 1.564 95.6 40.0 18.2 2022 09 03 16 44.27 -35 56.2 1.150 1.582 94.0 39.5 18.3 2022 09 08 16 59.32 -37 12.9 1.203 1.602 92.5 38.9 18.4 2022 09 13 17 14.79 -38 17.4 1.258 1.623 90.9 38.3 18.6 2022 09 18 17 30.58 -39 10.2 1.314 1.645 89.3 37.7 18.8 2022 09 23 17 46.61 -39 51.6 1.372 1.668 87.8 37.0 18.9 2022 09 28 18 02.78 -40 22.0 1.432 1.692 86.2 36.2 19.1 2022 10 03 18 19.01 -40 42.0 1.494 1.718 84.6 35.5 19.2 2022 10 08 18 35.19 -40 52.2 1.557 1.744 82.9 34.7 19.4 2022 10 13 18 51.26 -40 53.2 1.622 1.770 81.3 33.9 19.5 2022 10 18 19 07.12 -40 45.7 1.688 1.798 79.6 33.0 19.7 2022 10 23 19 22.74 -40 30.3 1.755 1.826 77.8 32.2 19.8 2022 10 28 19 38.07 -40 07.6 1.824 1.855 76.1 31.3 20.0 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 June 27 (CBET 5137) Daniel W. E. Green