Electronic Telegram No. 2958 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; 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/2011 Y2 (BOATTINI) A. Boattini reports his discovery of a comet on CCD images taken with the Mount Lemmon 1.5-m reflector (discovery observations tabulated below), the object described as having a very condensed 5" coma and no sign of a tail in 3" seeing. After posting on the Minor Planet Center's NEOCP webpage, other CCD astrometrists have also commented on the object's cometary appearance. Stacked images taken by R. Holmes (Ashmore, IL, USA; 0.61-m f/4.0 astrograph; measured by L. Buzzi, H. Devore, S. Foglia, and T. Vorobjov) on Dec. 25.1 UT show a round 10" coma; follow-up images taken by Holmes on Dec. 26.0 show a 10" coma with a slight elongation in p.a. 135 deg. Stacked images taken by Luca Buzzi (Varese, Italy; 0.38-m f/6.8 reflector) on Dec. 25.8 show an 8" coma slightly elongated in p.a. 140 deg. H. Sato (Tokyo, Japan; remotely using a 0.43-m f/4.5 reflector at the RAS Observatory, Nerpio, Spain, on Dec. 25.8) found a 10" coma in stacked images; he measured magnitude V = 19.7 in a circular aperture of radius 4".2. Co-added mages taken by P. Bacci, L. Tesi, and G. Fagioli with a 0.60-m f/4 reflector at San Marcello Pistoiese, Italy, on Dec. 27.7 show a diffuse coma of diameter 14" elongated in p.a. 103 deg. 2011 UT R.A. (2000) Decl. Mag. Observer Dec. 24.12799 0 17 37.71 +10 19 53.8 19.4 Boattini 24.13492 0 17 38.22 +10 19 56.1 19.4 " 24.14186 0 17 38.68 +10 19 58.3 19.2 " 24.14876 0 17 39.19 +10 20 00.3 19.3 " 24.18620 0 17 41.82 +10 20 10.9 19.6 " 24.19153 0 17 42.18 +10 20 12.3 19.1 " 24.19693 0 17 42.54 +10 20 14.1 19.8 " 24.20221 0 17 42.90 +10 20 15.5 19.8 " The available astrometry -- including prediscovery Mt. Lemmon observations from Oct. 30, as well as Pan-STARRS observations from Sept. 4 (giving the mag as 22.3-22.6) and Spacewatch observations from Oct. 16 (mag 20.5-20.8) -- together with the following orbital elements by G. V. Williams and an ephemeris, appear on MPEC 2011-Y49. Epoch = 2012 Mar. 14.0 TT T = 2012 Mar. 21.7042 TT Peri. = 131.1846 e = 0.712545 Node = 310.0120 2000.0 q = 1.787393 AU Incl. = 6.3519 a = 6.217997 AU n = 0.0635665 P = 15.50 years NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 December 28 (CBET 2958) Daniel W. E. Green