------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 2784 2011 Dec 03 16.15UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- COMET C/2011 W3 (LOVEJOY) Terry Lovejoy, Australia, reports his discovery of a comet on CCD images of 2011 Nov. 27.7 and 29.7UT with a 0.20-m f/2.1 Schmidt-Cassegrain reflector + CCD in the course of his comet-search program. The comet appears as a diffuse circular object about 1' in diameter, with a central condensation of mag 16 and no apparent tail. By Dec. 1.7, Lovejoy found that the comet had brightened by perhaps a magnitude and was now well-condensed with a 1'.2 coma. Selected astrometry by Lovejoy: 2011 UT R.A. (2000) Decl. Mag. Observer Nov. 27.73470 12 47 38.8 -51 39 29 13 Lovejoy 27.74650 12 47 51.8 -51 39 50 " 29.72801 13 27 30.5 -52 18 25 13 " 29.72953 13 27 31.8 -52 18 30 " Dec. 1.73183 14 09 33.9 -52 00 41 12 " 1.73274 14 09 34.7 -52 00 44 " A. C. Gilmore and P. M. Kilmartin report that their CCD images of Dec. 1.6 with the Mount John 1.0-m f/7.7 reflector show a well-condensed, circular coma of diameter of 1' (and a nuclear condensation of mag 16.6-17.3) with no tail visible in a 60-s exposure. Following an appeal by the Minor Planet R. Holmes, USA reports that stacked CCD observations obtained by Holmes, T. Linder, and V. Hoette with a 0.41-m f/11 Ritchey-Chretien reflector at Cerro Tololo on Dec. 2.3 show a 14" round coma with a very broad 51" tail extending predominately in PA 327deg. Orbital elements by Gareth Williams: T = 2011 Dec. 16.0000 TT Peri. = 57.1427 Node = 332.0232 2000.0 q = 0.005894 AU Incl. = 135.9356 The comet appears to be a Kreutz sungrazer. The following ephemeris assumes H = 14.0 and 2.5n = 8. Note that the rate of brightness increase is highly uncertain. Date TT R. A. (2000) Decl. Delta r Elong. Mag 2011 12 03 14 36.33 -51 17.0 0.697 0.603 37.2 12.0 2011 12 04 14 57.02 -50 24.3 0.698 0.571 34.6 11.8 2011 12 05 15 16.98 -49 16.2 0.702 0.538 31.9 11.6 2011 12 06 15 35.96 -47 53.6 0.708 0.505 29.3 11.4 2011 12 07 15 53.78 -46 18.1 0.716 0.470 26.5 11.2 2011 12 08 16 10.34 -44 31.1 0.727 0.434 23.8 10.9 2011 12 09 16 25.59 -42 34.2 0.742 0.397 21.1 10.6 2011 12 10 16 39.54 -40 28.8 0.759 0.358 18.5 10.3 2011 12 11 16 52.22 -38 15.8 0.780 0.316 15.8 10.0 2011 12 12 17 03.68 -35 55.6 0.804 0.272 13.1 9.5 2011 12 13 17 13.96 -33 27.7 0.833 0.223 10.4 8.9 Extreme care is needed due to the comet's small solar elongation angle and close proximity to the Sun in the sky. Guy M Hurst -- Guy Hurst