Electronic Telegram No. 5257 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/2019 M4 (TESS) In June 2022, astrometry of an apparently asteroidal object that was discovered with the Transiting Exoplanet Survey Satellite (TESS) was reported to the Minor Planet Center (discovery observations tabulated below). The TESS is in a highly elliptical high-earth orbit (in a lunar-resonant orbit) has four 10-cm f/1.4 camera lenses with a 24 deg x 24 deg field-of-view and a 600- to 1000-nm bandpass. The discovery observations tabulated below are from 2019; when P. Veres (MPC) noted a nearly-parabolic orbit, he posted it to the MPC's PCCP webpage in hopes of getting archival searches for additional observations. 2019 UT R.A. (2000) Decl. Mag. June 27.11424 1 19 29.25 -79 21 12.4 18.9 27.13507 1 19 30.18 -79 21 21.3 19.0 27.17674 1 19 34.53 -79 21 32.8 18.9 27.34341 1 19 45.52 -79 21 59.1 19.5 27.40591 1 19 49.84 -79 22 17.4 19.5 S. Deen (Simi Valley, CA, USA) reports that he has identified cometary images in publicly available archival data acquired with the Cerro Tololo 4-m telescope (+ DECam), with his astrometry tabulated below. 2019 UT R.A. (2000) Decl. Mag. July 19.43798 1 39 27.53 -80 43 15.2 18.9 Aug. 9.38022 1 41 23.89 -81 58 32.3 19.8 9.38375 1 41 23.78 -81 58 33.0 19.7 Sept.14.10354 0 52 55.14 -83 09 29.8 18.7 Dec. 9.06466 23 32 27.07 -76 11 35.0 19.4 22.13379 23 40 22.93 -74 30 25.8 19.6 22.13722 23 40 23.07 -74 30 24.2 19.0 Deen reports seeing cometary activity as follows. The July 19 image shows a slightly condensed coma of size 1".5 (full-width-at-half-maximum) in 0".8 seeing and a somewhat-faint 7" tail in p.a. 225 degrees. On Aug. 9, there was a slightly diffuse coma of size 1".5 (FWHM) in 1" seeing and a 12" tail in p.a. 224 degrees. On Sept. 14, there was a slightly condensed coma of size 2".5 (FWHM) in 1".5 seeing and a broad 7"-long tail spanning p.a. 250-275 degrees. On Dec. 9, there was a very condensed coma of size 1".25 (FWHM) in 0".6 seeing and a 10"-long tail in p.a. 231 degrees. On Dec. 22, there was a very condensed coma of size 1".25 (FWHM) in 0".6 seeing and a 18" tail in p.a. 228 degrees. The available astrometry appears on MPEC 2023-J102. The following orbital elemments by S. Nakano (Central Bureau) are from 70 observations spanning 2019 June 27-Dec. 22 (mean residual 1".6), with corresponding original and future values of 1/a being +0.000015 and +0.000090 (+/- 0.000009) AU**-1, respectively. The comet passed 4.32 AU from Saturn on 2015 Feb. 9 and will pass 6.98 AU from Uranus on 2027 Oct. 28 UT. Epoch = 2019 Aug. 25.0 TT T = 2019 Sept.13.80240 TT Peri. = 260.43322 e = 1.0047744 Node = 52.56802 2000.0 q = 9.1817539 AU Incl. = 65.71048 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 6.5 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2023 05 16 02 55.19 -21 07.1 12.562 11.816 40.9 3.2 20.6 2023 05 26 02 58.49 -20 46.5 12.542 11.850 45.2 3.5 20.6 2023 06 05 03 01.64 -20 30.7 12.504 11.883 50.4 3.8 20.6 2023 06 15 03 04.56 -20 19.7 12.450 11.917 56.3 4.1 20.6 2023 06 25 03 07.20 -20 13.4 12.381 11.951 62.8 4.3 20.6 2023 07 05 03 09.48 -20 11.6 12.300 11.985 69.6 4.6 20.6 2023 07 15 03 11.37 -20 14.1 12.210 12.019 76.8 4.7 20.6 2023 07 25 03 12.80 -20 20.4 12.114 12.053 84.1 4.8 20.6 2023 08 04 03 13.72 -20 30.0 12.016 12.087 91.6 4.8 20.6 2023 08 14 03 14.10 -20 42.3 11.918 12.122 99.2 4.7 20.5 2023 08 24 03 13.91 -20 56.6 11.824 12.156 106.9 4.6 20.5 2023 09 03 03 13.14 -21 12.0 11.739 12.191 114.4 4.3 20.5 2023 09 13 03 11.80 -21 27.4 11.667 12.225 121.7 4.0 20.5 2023 09 23 03 09.92 -21 41.8 11.610 12.260 128.5 3.7 20.5 2023 10 03 03 07.56 -21 54.1 11.572 12.295 134.6 3.3 20.5 2023 10 13 03 04.79 -22 03.2 11.556 12.330 139.3 3.0 20.5 2023 10 23 03 01.71 -22 08.2 11.565 12.365 142.1 2.8 20.6 2023 11 02 02 58.44 -22 08.3 11.598 12.400 142.5 2.8 20.6 2023 11 12 02 55.12 -22 02.9 11.657 12.436 140.4 2.9 20.6 2023 11 22 02 51.87 -21 51.7 11.741 12.471 136.0 3.2 20.6 2023 12 02 02 48.83 -21 34.7 11.849 12.506 130.1 3.5 20.6 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 May 12 (CBET 5257) Daniel W. E. Green