Electronic Telegram No. 5026 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/2021 Q2 = P/2011 A2 (SCOTTI) The Minor Planet Center (cf. MPEC 2021-Q69) has reported that comet P/2011 A2 (cf. IAUCs 9192, 9204) has been recovered in images obtained by B. T. Bolin with the 1.2-m Oschin Schmidt telescope at Palomar (astrometry tabulated below), with nothing stated about the comet's appearance. 2021 UT R.A. (2000) Decl. Mag. Observer Aug. 20.50218 7 31 15.27 +23 44 54.4 18.5 Bolin 20.50454 7 31 15.69 +23 44 53.7 18.6 " 20.50671 7 31 16.22 +23 44 53.4 19.5 " 20.50690 7 31 16.07 +23 44 53.2 18.5 " 20.50908 7 31 16.66 +23 44 52.9 19.7 " 20.50927 7 31 16.48 +23 44 52.6 18.6 " 20.51163 7 31 16.85 +23 44 52.3 18.7 " 23.50442 7 39 39.13 +23 30 15.5 18.5 " 23.50681 7 39 39.53 +23 30 14.4 18.2 " 23.50922 7 39 39.93 +23 30 14.1 18.3 " 23.51162 7 39 40.30 +23 30 13.0 18.4 " 24.50368 7 42 27.29 +23 25 00.2 18.6 " 24.50609 7 42 27.75 +23 24 59.4 18.3 " 24.51089 7 42 28.46 +23 24 57.9 18.5 " 25.50317 7 45 15.97 +23 19 34.0 18.6 " 25.50579 7 45 16.38 +23 19 33.7 18.6 " 25.50798 7 45 16.77 +23 19 32.3 18.8 " 25.51037 7 45 17.18 +23 19 32.2 18.8 " 25.51278 7 45 17.49 +23 19 32.2 18.5 " The residuals of the recovery observations were -16'.0 in R.A. and +1'.8 in Decl. from the prediction in NK 2493 and 3673 and in the ICQ's 2015 and 2021 Comet Handbooks, with a corresponding correction of Delta(T) = +0.79 day. The comet was not observed at its 2016 return. The comet passed 0.41 AU from Jupiter in 1986 April and 0.89 AU from the earth on 2011 Apr. 3 UT. The following linked orbital elements by S. Nakano (CBAT) are from 252 observations spanning 2011-2021 (mean residual 0".7). Epoch = 2010 Dec. 30.0 TT T = 2010 Dec. 22.50367 TT Peri. = 94.58844 e = 0.4986534 Node = 54.72698 2000.0 q = 1.5587890 AU Incl. = 4.47399 a = 3.1092043 AU n = 0.17977537 P = 5.48 years Epoch = 2016 June 21.0 TT T = 2016 June 14.33106 TT Peri. = 94.64809 e = 0.4999408 Node = 54.67553 2000.0 q = 1.5528914 AU Incl. = 4.47537 a = 3.1054150 AU n = 0.18010452 P = 5.47 years Epoch = 2021 Dec. 12.0 TT T = 2021 Dec. 2.23421 TT Peri. = 94.50317 e = 0.4996221 Node = 54.67414 2000.0 q = 1.5546529 AU Incl. = 4.47479 a = 3.1069573 AU n = 0.17997043 P = 5.48 years Epoch = 2027 June 4.0 TT T = 2027 May 22.35786 TT Peri. = 94.49638 e = 0.5007326 Node = 54.62990 2000.0 q = 1.5492621 AU Incl. = 4.47633 a = 3.1030709 AU n = 0.18030864 P = 5.47 years Epoch = 2032 Nov. 24.0 TT T = 2032 Nov. 8.06772 TT Peri. = 94.42640 e = 0.4994663 Node = 54.62859 2000.0 q = 1.5546459 AU Incl. = 4.47488 a = 3.1059766 AU n = 0.18005567 P = 5.47 years The following ephemeris by the undersigned from the above orbital elements uses photometric power-law parameters H = 15.0 and 2.5n = 10 for the magnitudes. Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2021 08 14 07 13.22 +24 11.0 2.613 1.869 34.5 17.9 19.8 2021 08 24 07 41.04 +23 27.7 2.512 1.821 37.8 19.9 19.6 2021 09 03 08 09.30 +22 25.7 2.412 1.776 40.8 21.8 19.4 2021 09 13 08 37.88 +21 05.0 2.314 1.734 43.8 23.7 19.2 2021 09 23 09 06.62 +19 25.9 2.219 1.695 46.6 25.5 19.0 2021 10 03 09 35.40 +17 29.4 2.128 1.660 49.3 27.2 18.8 2021 10 13 10 04.08 +15 17.4 2.042 1.629 52.0 28.8 18.7 2021 10 23 10 32.55 +12 52.2 1.960 1.603 54.6 30.4 18.5 2021 11 02 11 00.74 +10 16.6 1.883 1.582 57.2 31.8 18.4 2021 11 12 11 28.53 +07 34.1 1.811 1.567 59.8 33.1 18.2 2021 11 22 11 55.84 +04 48.5 1.743 1.558 62.5 34.2 18.1 2021 12 02 12 22.57 +02 03.4 1.680 1.555 65.4 35.2 18.0 2021 12 12 12 48.59 -00 37.2 1.620 1.558 68.5 36.0 18.0 2021 12 22 13 13.74 -03 10.0 1.563 1.567 71.9 36.6 17.9 2022 01 01 13 37.86 -05 32.1 1.507 1.581 75.6 37.0 17.9 2022 01 11 14 00.68 -07 41.0 1.453 1.602 79.7 37.2 17.9 2022 01 21 14 21.92 -09 35.3 1.399 1.627 84.3 37.0 17.8 2022 01 31 14 41.23 -11 14.3 1.345 1.658 89.4 36.5 17.8 2022 02 10 14 58.20 -12 37.5 1.291 1.693 95.1 35.5 17.8 2022 02 20 15 12.37 -13 45.7 1.238 1.732 101.5 34.0 17.8 2022 03 02 15 23.29 -14 39.8 1.186 1.774 108.8 31.9 17.9 2022 03 12 15 30.45 -15 20.8 1.139 1.819 117.0 29.1 17.9 2022 03 22 15 33.51 -15 49.8 1.098 1.867 126.1 25.6 17.9 2022 04 01 15 32.32 -16 07.7 1.067 1.917 136.2 21.2 18.0 2022 04 11 15 27.13 -16 15.4 1.050 1.968 147.2 16.0 18.0 2022 04 21 15 18.79 -16 14.2 1.051 2.021 158.9 10.3 18.2 2022 05 01 15 08.62 -16 06.5 1.074 2.075 171.0 4.4 18.3 2022 05 11 14 58.24 -15 56.0 1.121 2.130 176.6 1.6 18.5 2022 05 21 14 49.17 -15 47.6 1.192 2.186 165.0 6.9 18.8 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2021 CBAT 2021 August 31 (CBET 5026) Daniel W. E. Green