Electronic Telegram No. 2088 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 C/2009 Y2 (KOWALSKI) R. A. Kowalski, Lunar and Planetary Laboratory, reports a cometary object (discovery observation below) with the 0.68-m Schmidt at the Catalina Sky Survey; in good seeing, it appeared more diffuse than a typical object of comparable brightness and showed what appeared to be a round coma with strong condensation in p.a. 270 deg. Observations by A. R. Gibbs with the Mt. Lemmon 1.5-m reflector on Dec. 20.2 UT showed a 4".5 broad tail in p.a. 45 deg. After the discovery had been added to the NEO Confirmation Page, W. H. Ryan and E. V. Ryan (Magdalena Ridge Observatory, 2.4-m f/8.9 reflector) on Dec. 20.2 and 21.1 confirmed a faint tail in p.a. 45 deg. A 105-min integration by P. Birtwhistle (Great Shefford, Berkshire, England, 0.40-m f/6.0 Schmidt-Cassegrain) on Dec. 20.9 showed the object to have a diameter of about 6" with a 10" extension in p.a. 50 deg; a faint, straight tail was suspected, also in p.a. 50 deg, at least 25" and possibly up to 45" long. 2009 UT R.A. (2000) Decl. Mag. Observer Dec. 20.11774 00 37 55.48 +31 27 27.2 18.9 Kowalski Further astrometry, the following parabolic orbital elements and an ephemeris are given on MPEC 2009-Y40. T = 2010 Apr. 2.849 TT Peri. = 177.247 Node = 260.726 2000.0 q = 2.29149 AU Incl. = 30.655 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 December 21 (CBET 2088) Brian G. Marsden