Electronic Telegram No. 5216 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 E3 (ZTF) N. Biver, D. Bockelee-Morvan, and J. Crovisier, LESIA, Observatoire de Paris; Aa. Sandqvist, Stockholm Observatory; S. Lundin and M. Battelino, OHB Sweden; and the Odin team report observations of the water rotational line at 557 GHz in comet C/2022 E3 (ZTF) with the Odin space telescope from January 19.3 to 20.3 UT. The line intensity peaks at 6.8 +/- 0.1 K km s-1 within the 2' beam, corresponding to a water-production rate of 6.5 (+/- 1.0) x 10**28 molecules/s. Selected visual total-magnitude and coma-diameter estimates: 2022 Aug. 1.02 UT, 12.5, 0'.6 (J. J. Gonzalez, Palencia, Spain, 0.20-m reflector); 3.92, 12.9, 0'.4 (W. Hasubick, Buchloe, Germany, 44-cm reflector); 14.99, 12.1, 1' (J. G. de S. Aguiar, Campinas, Brazil, 0.27-m reflector); Sept. 1.99, 12.6, 1' (Aguiar); 19.83, 11.4, 2'.2 (Gonzalez, Asturias, Spain); 23.98, 11.8, 2' (Aguiar); Oct. 17.75, 10.9, 1'.0 (Hasubick); Dec. 2.24, 9.2, 3' (Gonzalez, Leon, Spain); 21.52, 7.8, 6' (C. Hergenrother, Tucson, AZ, USA, 10x50 binoculars); 24.81, 8.2, 2' (Y. Nagai, Saitama, Japan, 0.32-m reflector); 31.85, 7.4, 8' (K. Yoshimoto, Yamaguchi, Japan, 8x42 binoculars); 2023 Jan. 2.12, 7.0, 10' (V. Gonano, Udine, Italy, 10x50 binoculars); 2.81, 7.3, 7' (Nagai, 15x70 binoculars); 3.20, 6.7, 10' (Gonzalez, Asturias, Spain, 10x50 binoculars); 4.88, 6.9, 12' (Yoshimoto); 10.14, 7.5, 9'.5 (Gonano); 10.84, 6.8, 12' (Yoshimoto); 14.52, 6.5, 12' (Hergenrother); 16.18, 6.5, 6'.6 (Hasubick, 10x50 binoculars); 18.46, 6.3, 12' (C. S. Morris, Fillmore, CA, U.S.A., 10x50 binoculars); 20.76, 5.7, 20' (Yoshimoto); 21.41, 5.5, 15' (Hergenrother, 2x12 binoculars); 22.35, 5.8, 15' (Morris; 6.0-deg gas tail); 24.41, 5.6, 21' (Morris; 5.5-deg gas tail; 0.83-deg dust fan); 25.51, 5.2, 25' (Hergenrother); 26.41, 5.2, 20' (Morris; 10.0-deg gas tail; 2.75-deg dust tail); 27.42, 5.0, 20' (Morris; 9.0-deg gas tail; 4.5-deg dust tail); 28.43, 4.8, 23' (Morris; 15-deg gas tail; 4.0-deg dust tail); 29.52, 5.1, 6' (Hergenrother, naked eye); 29.81, 4.8, 7'.1 (Hasubick, 10x50 binoculars); 31.18, 4.6, 25' (Gonzalez, Leon, Spain, naked eye); Feb. 1.25, 4.5, 25' (Gonzalez). On 2022 Dec. 31.87 UT, K. Yoshimoto (Yamaguchi, Japan) found total magnitude 7.6 and coma 11'.9 with a tail more than 5 deg long in p.a. 320 degrees using a CMOS detector with a 0.08-m f/4.3 refractor (+ V filter). The following updated orbital elements by S. Nakano (Central Bureau) are from 5093 observations spanning 2021 July 10-2023 Jan. 27 (mean residual 0".5), with corresponding original and future values of 1/a being +0.000709 and -0.000006 AU**-1, respectively. Observations in late Jan. 2023 show residuals of -6" mainly in Decl. from an orbit on NK 4880. The comet passed 1.18 AU from Saturn on 2020 May 29 and 3.07 AU from Jupiter on 2021 Apr. 3; closest approach to the earth occurred on 2023 Feb. 1.8 UT. Epoch = 2023 Jan. 16.0 TT T = 2023 Jan. 12.78453 TT Peri. = 145.81473 e = 1.0003295 Node = 302.55570 2000.0 q = 1.1122458 AU Incl. = 109.16912 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 7.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2023 01 16 15 44.25 +42 34.4 0.616 1.113 84.9 61.6 6.3 2023 01 21 15 32.67 +51 13.0 0.479 1.120 93.5 61.3 5.8 2023 01 26 14 53.43 +65 54.6 0.361 1.133 105.0 57.1 5.2 2023 01 31 08 44.67 +79 19.5 0.290 1.151 118.3 48.9 4.8 2023 02 05 05 17.12 +52 00.3 0.304 1.174 121.7 45.6 5.0 2023 02 10 04 50.60 +29 24.4 0.395 1.203 114.0 48.6 5.6 2023 02 15 04 42.13 +16 27.2 0.523 1.235 105.5 50.4 6.3 2023 02 20 04 38.95 +08 52.5 0.667 1.271 98.4 50.3 7.0 2023 02 25 04 38.09 +04 04.6 0.817 1.311 92.6 48.9 7.5 2023 03 02 04 38.52 +00 48.6 0.968 1.354 87.5 47.0 8.0 2023 03 07 04 39.76 -01 32.8 1.118 1.399 82.9 44.7 8.4 2023 03 12 04 41.56 -03 19.7 1.266 1.447 78.6 42.3 8.8 2023 03 17 04 43.81 -04 43.7 1.411 1.497 74.7 39.9 9.1 2023 03 22 04 46.40 -05 52.1 1.552 1.548 71.0 37.5 9.5 2023 03 27 04 49.29 -06 49.5 1.689 1.600 67.5 35.2 9.8 2023 04 01 04 52.41 -07 39.4 1.822 1.654 64.2 33.0 10.1 2023 04 06 04 55.73 -08 23.9 1.950 1.708 61.1 30.8 10.3 2023 04 16 05 02.88 -09 42.9 2.190 1.820 55.4 27.0 10.8 2023 04 26 05 10.55 -10 55.6 2.410 1.933 50.5 23.7 11.2 2023 05 06 05 18.58 -12 07.9 2.607 2.048 46.5 20.9 11.6 2023 05 16 05 26.86 -13 23.4 2.782 2.163 43.5 18.8 11.9 2023 05 26 05 35.28 -14 44.9 2.935 2.278 41.6 17.2 12.2 2023 06 05 05 43.71 -16 14.4 3.066 2.393 40.9 16.1 12.5 2023 06 15 05 52.06 -17 53.6 3.177 2.508 41.5 15.6 12.7 2023 06 25 06 00.22 -19 43.9 3.269 2.622 43.2 15.4 12.9 2023 07 05 06 08.07 -21 46.4 3.343 2.736 46.0 15.5 13.1 2023 07 15 06 15.47 -24 01.9 3.401 2.849 49.6 15.8 13.3 2023 07 25 06 22.29 -26 31.0 3.445 2.961 53.8 16.1 13.5 2023 08 04 06 28.34 -29 14.0 3.479 3.073 58.4 16.3 13.6 2023 08 14 06 33.42 -32 10.5 3.505 3.183 63.4 16.5 13.7 2023 08 24 06 37.26 -35 19.9 3.526 3.293 68.5 16.6 13.9 2023 09 03 06 39.57 -38 40.5 3.546 3.401 73.6 16.5 14.0 2023 09 13 06 39.95 -42 09.5 3.568 3.509 78.5 16.3 14.1 2023 09 23 06 37.92 -45 43.2 3.595 3.616 83.2 16.0 14.2 2023 10 03 06 32.92 -49 16.2 3.631 3.722 87.4 15.6 14.4 2023 10 13 06 24.33 -52 41.6 3.678 3.827 91.0 15.1 14.5 2023 10 23 06 11.53 -55 51.1 3.739 3.931 93.7 14.6 14.6 2023 11 02 05 54.16 -58 35.2 3.815 4.035 95.6 14.2 14.8 2023 11 12 05 32.35 -60 44.7 3.907 4.138 96.5 13.8 14.9 2023 11 22 05 07.11 -62 11.8 4.015 4.240 96.3 13.4 15.0 2023 12 02 04 40.39 -62 52.7 4.138 4.341 95.3 13.1 15.2 2023 12 12 04 14.60 -62 49.3 4.273 4.441 93.4 12.8 15.3 2023 12 22 03 51.85 -62 08.0 4.419 4.541 90.8 12.5 15.5 2024 01 01 03 33.35 -60 58.3 4.573 4.639 87.7 12.2 15.6 2024 01 11 03 19.39 -59 30.0 4.733 4.738 84.3 11.9 15.8 2024 01 21 03 09.68 -57 51.5 4.895 4.835 80.7 11.6 15.9 2024 01 31 03 03.63 -56 09.5 5.056 4.932 77.1 11.2 16.1 2024 02 10 03 00.59 -54 28.8 5.215 5.028 73.7 10.9 16.2 2024 02 20 03 00.00 -52 53.1 5.369 5.123 70.4 10.5 16.3 2024 03 01 03 01.34 -51 24.7 5.515 5.218 67.6 10.1 16.4 2024 03 11 03 04.21 -50 05.4 5.652 5.312 65.2 9.8 16.6 2024 03 21 03 08.28 -48 56.4 5.779 5.406 63.3 9.5 16.7 2024 03 31 03 13.26 -47 58.6 5.894 5.499 62.1 9.2 16.8 2024 04 10 03 18.93 -47 12.5 5.998 5.591 61.6 9.1 16.9 2024 04 20 03 25.11 -46 38.6 6.089 5.683 61.8 9.0 17.0 2024 04 30 03 31.62 -46 17.2 6.168 5.774 62.6 8.9 17.0 2024 05 10 03 38.31 -46 08.3 6.235 5.865 64.1 8.9 17.1 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 February 4 (CBET 5216) Daniel W. E. Green