Electronic Telegram No. 5106 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 A3 (LEMMON-ATLAS) An apparently asteroidal object discovered on CCD images taken on Mar. 1 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 has been found to show cometary appearance by CCD astrometrists elsewhere after it was posted on the Minor Planet Center's PCCP webpage. The discovery observations are tabulated below. 2022 UT R.A. (2000) Decl. Mag. Mar. 1.42136 10 19 15.99 +39 37 47.7 19.2 1.43901 10 19 14.76 +39 37 46.9 19.1 1.43992 10 19 14.66 +39 37 46.2 18.9 1.47528 10 19 12.37 +39 37 44.4 19.1 Earlier apparently asteroidal CCD observations obtained in January with the Mt. Lemmon Survey's 1.5-m reflector were then identified in the MPC's "isolated tracklet file" (which is visible publicly) that were reported as separate objects on each night but which should have been linked previously. The ITF Mt. Lemmon observations are tabulated below: 2022 UT R.A. (2000) Decl. Mag. Jan. 10.42680 11 05 01.05 +38 34 09.8 20.3 10.43215 11 05 00.82 +38 34 10.6 20.1 10.43749 11 05 00.69 +38 34 11.2 20.2 10.44283 11 05 00.47 +38 34 12.3 20.2 29.41413 10 50 47.73 +39 22 00.3 19.8 29.42028 10 50 47.40 +39 22 00.8 19.9 29.42639 10 50 47.09 +39 22 01.6 19.8 29.43251 10 50 46.77 +39 22 02.6 19.9 31.37108 10 49 02.41 +39 25 56.0 19.9 31.37638 10 49 02.13 +39 25 56.9 19.8 31.38169 10 49 01.82 +39 25 57.4 19.8 31.38700 10 49 01.54 +39 25 57.8 19.6 Feb. 22.39853 10 26 48.22 +39 44 26.4 19.9 22.40372 10 26 47.88 +39 44 26.3 19.5 22.40891 10 26 47.55 +39 44 26.2 19.6 22.41412 10 26 47.19 +39 44 25.8 19.6 E. Bryssinck, Kruibeke, Belgium, writes that forty stacked, 120-s unfiltered CCD images taken with a 0.4-m f/3.8 reflector on Mar. 3.8 UT show a compact, condensed, elongated coma of size 7" x 12" and a hint of a short tail about 6" long in p.a. 130 degrees; the magnitude was 19.5 as measured within a circular aperture of radius 5".5. Forty-five 60-s CCD exposures taken by L. Buzzi and A. Aletti, Varese, Italy, with a 0.84-m f/3.5 reflector in good conditions show a very condensed coma 5" wide with a faint extension toward the north. In addition, Mt. Lemmon observations from 2021 Apr. 30.2 (mag 22.1-22.6) and Dec. 1.5 UT were reported to the MPC after the object was posted online; all of the astrometry appear on MPEC 2022-E107. The following orbital elements by S. Nakano (Central Bureau) are from 104 observations spanning 2021 Apr. 30-2022 Mar. 6 (mean residual 0".4), with corresponding original and future values for 1/a of +0.001157 and +0.000980 AU**-1, respectively (formal error +/- 0.000012 AU**-1), with no close approaches to any major planets. Epoch = 2023 Sept.13.0 TT T = 2023 Sept.28.86676 TT Peri. = 234.84715 e = 0.9958084 Node = 325.47985 2000.0 q = 3.7035554 AU Incl. = 88.34333 The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 9.0 and 2.5n = 8 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2022 03 02 10 18.65 +39 36.9 5.255 6.110 147.0 5.1 18.9 2022 03 12 10 08.16 +39 14.7 5.253 6.049 140.0 6.1 18.9 2022 03 22 09 58.43 +38 38.6 5.281 5.987 131.5 7.2 18.8 2022 04 01 09 49.87 +37 50.2 5.333 5.926 122.2 8.2 18.8 2022 04 11 09 42.75 +36 51.4 5.405 5.865 112.7 9.1 18.8 2022 04 21 09 37.23 +35 44.5 5.492 5.804 103.2 9.7 18.8 2022 05 01 09 33.32 +34 31.7 5.589 5.744 93.8 10.1 18.8 2022 05 11 09 30.96 +33 14.9 5.690 5.684 84.5 10.2 18.8 2022 05 21 09 30.01 +31 55.5 5.791 5.624 75.5 10.0 18.8 2022 05 31 09 30.34 +30 34.6 5.887 5.564 66.7 9.6 18.8 2022 06 10 09 31.78 +29 12.9 5.974 5.505 58.1 9.0 18.8 2022 06 20 09 34.16 +27 50.8 6.048 5.446 49.7 8.2 18.8 2022 10 28 10 31.10 +09 50.0 5.164 4.721 58.4 10.3 18.0 2022 11 07 10 33.20 +08 24.7 4.959 4.669 67.4 11.3 17.8 2022 11 17 10 34.23 +06 59.1 4.744 4.619 76.7 12.0 17.7 2022 11 27 10 33.97 +05 33.2 4.524 4.569 86.4 12.4 17.6 2022 12 07 10 32.20 +04 07.4 4.303 4.520 96.3 12.5 17.4 2022 12 17 10 28.70 +02 41.9 4.088 4.472 106.7 12.2 17.3 2022 12 27 10 23.26 +01 17.3 3.884 4.425 117.4 11.4 17.1 2023 01 06 10 15.76 -00 05.4 3.699 4.378 128.5 10.1 17.0 2023 01 16 10 06.20 -01 25.0 3.537 4.333 139.6 8.5 16.8 2023 01 26 09 54.73 -02 39.6 3.407 4.290 150.2 6.5 16.7 2023 02 05 09 41.76 -03 47.4 3.313 4.247 158.7 4.8 16.6 2023 02 15 09 27.90 -04 46.8 3.258 4.205 161.3 4.3 16.6 2023 02 25 09 13.91 -05 36.7 3.243 4.165 155.8 5.6 16.5 2023 03 07 09 00.61 -06 17.4 3.265 4.126 146.1 7.7 16.5 2023 03 17 08 48.66 -06 50.3 3.321 4.089 135.3 9.9 16.5 2023 03 27 08 38.57 -07 17.4 3.405 4.052 124.4 11.7 16.5 2023 04 06 08 30.59 -07 41.5 3.509 4.018 113.8 13.2 16.6 2023 04 16 08 24.77 -08 05.2 3.626 3.985 103.7 14.2 16.6 2023 04 26 08 21.03 -08 30.8 3.750 3.953 94.2 14.7 16.6 2023 05 06 08 19.20 -09 00.4 3.875 3.923 85.3 14.8 16.7 2023 05 16 08 19.05 -09 35.4 3.997 3.895 77.0 14.6 16.7 2023 05 26 08 20.36 -10 17.0 4.111 3.869 69.2 14.2 16.8 2023 06 05 08 22.92 -11 06.4 4.213 3.844 62.1 13.5 16.8 2023 06 15 08 26.51 -12 04.3 4.302 3.821 55.6 12.7 16.8 2023 06 25 08 30.95 -13 11.4 4.376 3.801 49.8 11.8 16.8 2023 07 05 08 36.09 -14 28.3 4.433 3.782 44.9 10.9 16.9 2023 07 15 08 41.77 -15 55.7 4.473 3.765 41.0 10.2 16.9 2023 07 25 08 47.87 -17 34.2 4.494 3.750 38.2 9.7 16.9 2023 08 04 08 54.24 -19 24.3 4.499 3.737 36.9 9.4 16.8 2023 08 14 09 00.79 -21 26.6 4.487 3.726 36.9 9.4 16.8 2023 08 24 09 07.38 -23 41.8 4.459 3.717 38.2 9.7 16.8 2023 09 03 09 13.90 -26 10.5 4.417 3.711 40.7 10.2 16.8 2023 09 13 09 20.21 -28 53.0 4.363 3.706 44.1 10.9 16.8 2023 09 23 09 26.14 -31 50.0 4.298 3.704 48.1 11.6 16.7 2023 10 03 09 31.53 -35 01.6 4.227 3.704 52.5 12.4 16.7 2023 10 13 09 36.13 -38 27.5 4.150 3.706 57.2 13.1 16.6 2023 10 23 09 39.64 -42 07.2 4.073 3.710 61.9 13.7 16.6 2023 11 02 09 41.65 -45 59.2 3.997 3.716 66.6 14.2 16.6 2023 11 12 09 41.62 -50 01.1 3.926 3.724 71.1 14.6 16.5 2023 11 22 09 38.76 -54 09.2 3.863 3.735 75.2 14.8 16.5 2023 12 02 09 31.97 -58 17.8 3.812 3.747 78.8 15.0 16.5 2023 12 12 09 19.70 -62 18.9 3.773 3.762 81.8 15.0 16.5 2023 12 22 08 59.92 -66 01.3 3.750 3.779 84.1 15.0 16.5 2024 01 01 08 30.44 -69 10.1 3.742 3.797 85.7 15.0 16.5 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 March 7 (CBET 5106) Daniel W. E. Green