Electronic Telegram No. 3010 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 VJ5 (LEMMON) R. E. Hill reported his finding a comet with a coma diameter of about 6"-8", no well-defined nuclear condensation, and a narrow tail 12"-14" long in p.a. 280 deg on four co-added 30-s CCD exposures taken in seeing of about 3"-4" with the Catalina Sky Survey's 0.68-m Schmidt telescope (astrometry tabulated below). Hill's four co-added 60-s exposures taken as follow-up on Feb. 1.5 UT show a coma about 8" across with a tiny nuclear condensation of diameter about 2"-3" and a tail 14"-16" long in p.a. 280 deg; his additional images taken on Feb. 2.5 show a 3"-4" nuclear condensation with little coma and a narrow tail 12"-14" long in poor seeing with thin haze. Follow-up CCD images taken by A. R. Gibbs with the Mt. Lemmon 1.5-m reflector on Feb. 1.52 show a starlike central condensation and a thin tail 90" long (width 7") in p.a. 114 deg in four co-added 45-s exposures. After posting the object on the Minor Planet Center's NEOCP webpage now, other CCD astrometrists also have remarked on the object's cometary appearance. Stacked R-band images taken remotely by A. Tripp, G. Sostero, N. Howes, and E. Guido with the 2.0-m f/10 "Faulkes Telescope North" at Haleakala on Feb. 1.6 in good seeing show a compact coma nearly 3" in diameter with a sharp central condensation and a tail about 20" long in p.a. 292 deg. Forty-five co-added 30-s images taken by R. Holmes, T. Linder, and V. Hoette with a 0.41-m f/11 Ritchey-Chretien telescope at Cerro Tololo on Feb. 2.4 show a coma of diameter about 3".6 with a faint, narrow tail 10".5 long in p.a. 284 deg. T. Spahr, Minor Planet Center, noted that this object appears identical to an apparently asteroidal object discovered by the Mount Lemmon Survey on Nov. 3 (observer R. Kowalski; discovery observations tabulated below) and then designated 2011 VJ5 after having been posted on the NEOCP in November (with observations 2011 Nov. 3.5-5.1 having been published on MPS 398699). 2011 UT R.A. (2000) Decl. Mag. Observer Nov. 3.46432 9 29 05.82 +10 31 53.2 20.2 Kowalski 3.47189 9 29 07.11 +10 31 47.0 20.5 " 3.47954 9 29 08.34 +10 31 40.8 20.3 " 3.48711 9 29 09.60 +10 31 34.2 20.3 " 2012 UT R.A. (2000) Decl. Mag. Observer Feb. 1.47162 12 42 28.40 - 5 57 07.2 Hill 1.47669 12 42 28.80 - 5 57 08.4 18.5 " 1.48181 12 42 29.01 - 5 57 08.2 " 1.48687 12 42 29.19 - 5 57 09.5 " 1.49286 12 42 29.48 - 5 57 10.2 " 1.49888 12 42 29.91 - 5 57 10.6 " 1.50488 12 42 30.20 - 5 57 10.2 18.5 " 1.51098 12 42 30.60 - 5 57 11.4 " The new astrometry, the following elliptical orbital elements by G. V. Williams, and an ephemeris appear on MPEC 2012-C14. Epoch = 2011 Dec. 25.0 TT T = 2011 Dec. 8.7004 TT Peri. = 315.1262 e = 0.555652 Node = 169.9789 2000.0 q = 1.505907 AU Incl. = 3.9721 a = 3.389031 AU n = 0.1579759 P = 6.24 years NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 February 3 (CBET 3010) Daniel W. E. Green