Electronic Telegram No. 1790 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html COMET P/2009 H2 (McNAUGHT) Automatic procedures at the Minor Planet Center identified comet P/2004 K2 (cf. IAUC 8348) in incidental astrometry obtained by T. H. Bressi with the Spacewatch 0.9-m f/3 reflector on Apr. 28. Subsequently, recovery observations were independenty reported by G. Muler, J. M. Ruiz and R. Naves with the 0.30-m Schmidt-Cassegrain at the Observatorio Nazaret (Lanzarate, Spain) on May 1 and 3. No information was provided about the comet's appearance. Packed Desig. Date UT R.A. (2000.0) Decl. Mag. Obs PK09H020 C2009 04 28.36557 16 03 06.17 -07 33 49.0 691 PK09H020 C2009 04 28.38319 16 03 05.49 -07 33 42.3 691 PK09H020 C2009 04 28.40081 16 03 04.82 -07 33 36.0 691 PK09H020 C2009 05 01.04433 16 01 23.07 -07 18 04.3 20.2 J47 PK09H020 C2009 05 01.05848 16 01 22.45 -07 17 59.7 20.2 J47 PK09H020 C2009 05 01.07499 16 01 21.75 -07 17 53.6 20.2 J47 PK09H020 C2009 05 01.09033 16 01 21.10 -07 17 48.5 20.2 J47 PK09H020 C2009 05 01.11038 16 01 20.23 -07 17 41.2 20.3 J47 PK09H020 C2009 05 03.05734 15 59 59.04 -07 06 17.5 20.0 J47 PK09H020 C2009 05 03.05994 15 59 58.87 -07 06 16.9 19.9 J47 PK09H020 C2009 05 03.06591 15 59 58.58 -07 06 15.0 20.2 J47 The indicated correction to the prediction on MPC 56805 is Delta(T) = -0.08 day. The following improved orbital elements are from 155 observations spanning 2004 May 20-2009 May 3 (mean residual 0".7): Epoch = 2004 June 4.0 TT T = 2004 June 16.81457 TT Peri. = 180.77298 e = 0.5012692 Node = 150.12399 2000.0 q = 1.5544515 AU Incl. = 8.12289 a = 3.1168146 AU n = 0.17911734 P = 5.503 years Epoch = 2010 Jan. 4.0 TT T = 2009 Dec. 15.43207 TT Peri. = 180.75749 e = 0.5026812 Node = 150.11807 2000.0 q = 1.5486245 AU Incl. = 8.13271 a = 3.1139471 AU n = 0.17936480 P = 5.495 years Residuals in seconds of arc K045K E12 0.5- 0.1+ K048B D74 (3.4+ 1.8-) K04AB 213 0.5- 0.1+ K045K E12 1.3- 0.8+ K048D 704 0.2- 0.5- K04AB 213 0.5- 0.5+ K045K E12 1.9- 1.4+ K048D 704 0.2+ 0.4- K04AB 213 0.3- 0.4+ K045K E12 0.1- 0.7+ K048D 704 0.8- 0.2- K04AC 170 0.1+ 0.6+ K045N G90 0.5- 0.9+ K048D 704 0.1- 0.7+ K04AC 170 0.1+ 0.4+ K045N G90 0.2- 0.1+ K048D 704 0.2- 0.4- K04AC 170 0.1+ 0.3+ K045N G90 0.4- 0.6+ K048O 246 1.1- 0.1+ K04AD A33 0.4+ 0.1- K045N G90 1.6- 0.4+ K048O 246 0.4+ 0.2- K04AD A33 0.1+ 0.1- K045N G90 0.6+ 1.1+ K048O 246 1.4+ 0.0 K04AG 360 0.5+ 0.4+ K045N G90 0.3- 0.9+ K048O 246 1.6+ 0.8- K04AG 360 0.1+ 0.4+ K045N 703 0.2- 0.1+ K048R 703 (4.0- 2.0-) K04AI 118 1.2- 0.1+ K045N 703 (1.0- 2.2+) K048R 703 0.9- 0.7- K04AI 118 0.1+ 0.5- K045P 673 0.0 0.9+ K048R 703 (2.2- 0.3-) K04AN 213 0.0 0.3- K045P 673 1.3+ 0.6+ K048R 703 0.8- 1.4+ K04AN 213 0.1+ 0.2- K045P 673 0.2+ 0.4+ K048S 699 0.4+ 0.4- K04AN 213 0.3+ 0.1- K045P 673 0.7+ 0.5+ K048S 699 0.1- 1.0- K04AQ 850 0.1- 0.6+ K045P 673 1.5+ 1.0+ K048S 699 0.4- 0.8- K04AQ 850 0.1- 0.6+ K045P 474 0.8- 0.8+ K048S 699 0.1- 0.1+ K04B1 413 0.6+ 0.3+ K045P 474 1.8+ 0.5+ K0497 246 0.4- 0.1+ K04B2 683 0.2+ 1.6- K045P 474 0.2- 0.4- K0497 246 0.5+ 0.1- K04B2 683 (2.4- 2.1+) K045P 474 0.5- 0.1- K0497 246 0.4+ 0.2- K04B2 683 0.3- 1.1+ K045S 673 1.8+ 0.2+ K0497 246 1.0+ 0.2- K04B4 104 0.0 0.4+ K045S 673 1.2+ 0.3+ K0497 246 0.6+ 0.3+ K04B4 104 0.5+ 0.4+ K045S 673 1.6+ 0.3+ K0499 246 0.4+ 0.1+ K04B4 104 0.4+ 0.4+ K045U 413 0.2+ 0.3- K0499 246 0.7+ 0.1+ K04B6 360 0.2+ 0.5+ K045V 413 0.4+ 0.1- K0499 246 0.2+ 0.4+ K04B6 360 0.2+ 0.4+ K0467 413 0.4+ 0.7- K0499 246 0.2+ 0.0 K04BC 704 0.3+ 0.7+ K0468 204 0.6- 0.5- K0499 A32 0.6- 1.4- K04BC 704 0.9+ 0.6+ K046D 703 1.1- 0.9+ K0499 A32 0.9- 0.9- K04BC 704 0.6- 0.2- K046D 703 0.5- 0.3- K049A 046 0.9- 0.8+ K04BJ 213 0.5+ 0.6+ K046D 703 1.6- 0.9- K049A 046 1.3- 0.1- K04BJ 213 0.2- 1.1+ K046D 703 (2.2- 0.2-) K049A 046 1.4- 0.4- K04BT 118 0.1- 0.4- K046M 703 1.5- 0.9- K049A 046 1.6- 0.1+ K04BT 118 0.1- 0.3+ K046M 703 1.3- 0.0 K049H 017 0.2- 0.3- K04C8 360 0.3- 0.5+ K046M 703 1.4- 1.7- K049J 215 0.1+ 0.3- K04C8 360 0.0 0.1+ K046M 703 1.8- 0.7- K049J 118 0.7- 0.5- K04C8 360 0.3- 0.5+ K046R E12 0.4+ 1.3- K049J 118 1.0+ 0.7- K04CB 360 0.4+ 0.2+ K046R E12 0.2- 2.0- K049K 785 1.2- 0.4+ K04CB 360 0.8+ 0.3+ K046R E12 1.1+ 0.9- K049K 785 0.8- 0.6+ K04CB 360 0.3- 0.1+ K046R E12 0.7+ 1.5- K049K 785 1.0- 1.1- K04CB 561 0.5+ 0.3+ K046U 360 0.0 0.0 K049M 704 0.1- 1.3+ K04CB 561 1.8- 0.5+ K046U 360 0.2+ 0.2- K049M 704 0.5- 0.4+ K04CB 561 0.0 0.4- K046U 360 0.1+ 0.3+ K049M 704 0.7- 0.1- K094S 691 0.4- 0.1- K047C 413 0.6+ 0.1- K049M 704 0.4+ 1.4+ K094S 691 0.4- 0.4+ K047H 215 0.4+ 0.9- K049M 704 0.4+ 0.1- K094S 691 0.2- 0.5+ K047K 413 0.7+ 0.1+ K049O 704 0.2+ 0.3+ K0951 J47 0.7+ 0.9+ K047V 170 0.4+ 1.1- K049O 704 0.3+ 1.0+ K0951 J47 0.4+ 0.6+ K047V 170 0.6+ 0.7- K049O 704 0.5+ 1.0+ K0951 J47 0.5+ 0.9+ K048B 704 0.2+ 0.4- K049O 704 0.0 0.5+ K0951 J47 0.5+ 0.6+ K048B 704 0.5- 0.2+ K04A7 704 0.5+ 0.6+ K0951 J47 0.3+ 0.8+ K048B 704 0.2- 0.5- K04A7 704 0.4+ 0.2+ K0953 J47 1.6+ 1.2+ K048B 704 0.0 0.2- K04A7 704 0.2+ 1.3+ K0953 J47 0.8+ 0.9+ K048B 704 0.9- 0.5- K04A7 704 0.9+ 0.2- K0953 J47 0.5+ 0.7+ K048B D74 1.4+ 0.4- K04A7 704 0.0 1.3+ The following ephemeris assumes H_10 = 15.0: Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag. 2009 04 29 16 02.71 -07 30.0 1.579 2.529 155.1 9.6 20.0 2009 05 09 15 55.36 -06 32.1 1.488 2.473 163.4 6.7 19.8 2009 05 19 15 46.29 -05 39.6 1.422 2.416 165.9 5.8 19.6 2009 05 29 15 36.48 -04 58.6 1.382 2.360 159.9 8.5 19.4 2009 06 08 15 27.14 -04 34.6 1.366 2.303 150.2 12.6 19.3 2009 06 18 15 19.40 -04 30.9 1.371 2.246 139.9 16.9 19.2 2009 06 28 15 14.15 -04 48.7 1.394 2.190 129.9 20.9 19.1 2009 07 08 15 11.96 -05 27.0 1.430 2.134 120.5 24.2 19.1 2009 07 18 15 13.03 -06 22.9 1.475 2.078 111.8 27.0 19.0 2009 07 28 15 17.37 -07 33.6 1.525 2.024 103.8 29.2 19.0 2009 08 07 15 24.87 -08 55.6 1.578 1.970 96.6 30.8 18.9 2009 08 17 15 35.31 -10 25.5 1.630 1.918 89.9 31.9 18.9 2009 08 27 15 48.55 -12 00.2 1.681 1.868 83.9 32.5 18.8 2009 09 06 16 04.40 -13 36.4 1.730 1.819 78.4 32.9 18.8 2009 09 16 16 22.71 -15 10.9 1.776 1.774 73.4 32.9 18.7 2009 09 26 16 43.38 -16 40.3 1.820 1.731 68.8 32.7 18.7 2009 10 06 17 06.27 -18 01.2 1.860 1.691 64.5 32.3 18.6 2009 10 16 17 31.22 -19 09.9 1.898 1.656 60.6 31.7 18.6 2009 10 26 17 58.08 -20 02.9 1.935 1.624 57.0 30.9 18.5 2009 11 05 18 26.58 -20 36.8 1.971 1.598 53.7 30.0 18.5 2009 11 15 18 56.44 -20 49.0 2.007 1.577 50.6 29.0 18.5 2009 11 25 19 27.33 -20 37.3 2.045 1.562 47.7 27.9 18.5 2009 12 05 19 58.84 -20 00.8 2.085 1.552 44.9 26.6 18.5 2009 12 15 20 30.59 -18 59.8 2.128 1.549 42.3 25.3 18.5 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 May 3 (CBET 1790) Brian G. Marsden