Electronic Telegram No. 5113 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 C/2022 F2 (NEOWISE) The Minor Planet Center (cf. MPEC MPEC 2022-G83) reports the discovery by James M. Bauer (University of Maryland) of a comet in infrared exposures obtained during Mar. 30-Apr. 1 UT (discovery observations tabulated below, in which the listed optical-wavelength magnitude was roughly estimated based on past WISE and NEOWISE cometary observations) with the Near-Earth Object Wide- field Infrared Survey Explorer (or NEOWISE; formerly the WISE earth-orbiting satellite; cf. CBET 4225). Bauer noted a diffuse coma approximately 15" in size with a broad, 60"-long tail in p.a. 250-280 degrees in a stacked 46-micron image. 2022 UT R.A. (2000) Decl. Mag. Mar. 30.72060 18 56 47.89 -56 35 53.8 17 30.85125 18 57 05.51 -56 45 53.1 30.98190 18 57 23.26 -56 55 53.3 31.11242 18 57 41.11 -57 05 54.6 31.24307 18 57 59.17 -57 15 57.0 31.37372 18 58 17.23 -57 26 01.8 31.43904 18 58 26.34 -57 31 04.0 31.50437 18 58 35.52 -57 36 06.8 31.56906 18 58 44.56 -57 41 07.8 31.56918 18 58 44.56 -57 41 08.2 31.63489 18 58 53.83 -57 46 13.3 31.70022 18 59 03.08 -57 51 16.9 31.83086 18 59 21.67 -58 01 25.6 31.96151 18 59 40.37 -58 11 35.4 Apr. 1.09203 18 59 59.19 -58 21 45.9 After the comet was posted on the MPC's PCCP webpage, other CCD astrometrists have also commented on the cometary appearance. Sixteen stacked 30-s exposures taken remotely by H. Sato, Tokyo, Japan, on Apr. 2.8 UT using a 0.51-m f/6.8 astrograph located at Siding Spring, NSW, show a strongly condensed coma 20" in diameter with no tail; the magnitude was 16.6 as measured within a circular aperture of radius 11".5. E. Bryssinck, Kruibeke, Belgium, has measured sixty luminance-filtered 30-s exposures taken remotely on Apr. 3.4 by a large group of observers using a "Telescope Live" 0.61-m f/6.5 astrograph located at El Sauce, Chile, which show a central condensation inside a coma of diameter 19" and a hint of a broad tail 13" long in p.a. 283 degrees, with magnitude of 17.5-17.7 in an aperture of radius 5".5. C. Jacques, Belo Horizonte, MG, Brazil, finds a condensed 15" coma with no tail in one-hundred stacked 30-s exposures taken on Apr. 4.2 with a 0.45-m f/2.9 reflector at the SONEAR Observatory, Oliveria. Three 30-s exposures taken remotely by F. D. Romanov using an iTelescope 0.50-m f/6.8 reflector at Siding Spring Observatory on Apr. 4.79 show a very condensed coma 6" in diameter without tail; the magnitude was 17.2-17.4 (Gaia DR2 band) in an aperture of radius 5". The following parabolic orbital elements by S. Nakano (Central Bureau) are from 57 observations spanning 2022 Mar. 30-Apr. 5 (mean residual 0".3). T = 2022 Mar. 24.46977 TT Peri. = 201.41076 Node = 59.08449 2000.0 q = 1.5953767 AU Incl. = 97.46834 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 14.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 03 02 18 13.59 -29 06.6 1.707 1.624 68.2 34.5 17.3 2022 03 07 18 19.65 -32 42.2 1.612 1.613 72.1 35.8 17.2 2022 03 12 18 26.02 -36 44.1 1.520 1.604 76.1 37.0 17.1 2022 03 17 18 32.87 -41 15.9 1.434 1.599 80.1 37.8 16.9 2022 03 22 18 40.44 -46 20.9 1.355 1.596 84.0 38.4 16.8 2022 03 27 18 49.15 -52 00.7 1.286 1.596 87.7 38.7 16.7 2022 04 01 18 59.76 -58 14.5 1.229 1.599 91.1 38.7 16.6 2022 04 06 19 13.95 -64 57.3 1.186 1.604 94.0 38.5 16.5 2022 04 11 19 35.95 -71 57.9 1.160 1.613 96.2 38.1 16.5 2022 04 16 20 20.31 -78 54.5 1.152 1.625 97.6 37.7 16.5 2022 04 21 22 42.31 -84 35.0 1.162 1.639 98.0 37.4 16.5 2022 04 26 03 39.47 -83 45.1 1.189 1.655 97.5 37.1 16.6 2022 05 01 05 22.19 -78 22.4 1.233 1.675 96.2 36.7 16.7 2022 05 06 05 58.40 -72 50.2 1.289 1.696 94.4 36.4 16.9 2022 05 11 06 17.68 -67 47.1 1.357 1.720 92.1 35.9 17.0 2022 05 16 06 30.49 -63 19.2 1.433 1.746 89.5 35.4 17.2 2022 05 21 06 40.18 -59 26.1 1.515 1.774 86.8 34.7 17.4 2022 05 26 06 48.11 -56 05.1 1.602 1.804 84.0 33.9 17.6 2022 05 31 06 54.95 -53 13.2 1.691 1.836 81.3 33.1 17.8 2022 06 05 07 01.05 -50 47.0 1.781 1.869 78.7 32.2 17.9 2022 06 10 07 06.61 -48 43.2 1.871 1.904 76.2 31.2 18.1 2022 06 15 07 11.75 -46 59.1 1.961 1.940 73.8 30.2 18.3 2022 06 20 07 16.54 -45 32.3 2.048 1.977 71.5 29.2 18.4 2022 06 25 07 21.06 -44 20.6 2.133 2.016 69.5 28.2 18.6 2022 06 30 07 25.32 -43 22.5 2.215 2.055 67.6 27.2 18.7 2022 07 05 07 29.34 -42 36.5 2.294 2.096 65.9 26.3 18.9 2022 07 10 07 33.13 -42 01.3 2.369 2.138 64.4 25.4 19.0 2022 07 15 07 36.69 -41 35.8 2.440 2.180 63.2 24.6 19.1 2022 07 20 07 40.02 -41 19.2 2.507 2.223 62.2 23.9 19.3 2022 07 25 07 43.11 -41 10.7 2.570 2.267 61.4 23.2 19.4 2022 07 30 07 45.96 -41 09.8 2.627 2.311 60.9 22.6 19.5 2022 08 04 07 48.54 -41 15.8 2.681 2.356 60.6 22.1 19.6 2022 08 09 07 50.83 -41 28.4 2.729 2.401 60.6 21.6 19.7 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 April 6 (CBET 5113) Daniel W. E. Green