Electronic Telegram No. 4018 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/2014 W1 (PANSTARRS) Eva Schunova, Richard Wainscoat, and Bryce Bolin report the discovery of a comet in four w-band CCD exposures taken with the 1.8-m Pan-STARRS1 telescope at Haleakala on Nov. 17 (discovery observations tabulated below); the object was non-stellar in appearance, with its core extended in the east-west direction with a hint of a tail towards the southeast. 2014 UT R.A. (2000) Decl. Mag. Nov. 17.35105 4 42 27.14 +22 33 00.3 20.9 17.36392 4 42 26.61 +22 32 56.7 20.9 17.37680 4 42 26.08 +22 32 53.2 20.9 17.38967 4 42 25.56 +22 32 49.6 21.0 M. Micheli and Wainscoat analyzed three 60-s r-band follow-up CCD images of the comet taken by Wainscoat and A. Draginda on Nov. 18.5 UT with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea, finding a starlike core with a halo of diffuse light surrounding the core (FWHM about 0".8 in 0".5 seeing) that is not present in nearby stars and a broad extension at p.a. about 115 deg. Four additional 45-s w-band exposures obtained with the Pan-STARRS1 telescope by Bolin and Wainscoat on Nov. 19.4 show a clearly non-stellar symmetric appearance (mag 20.1-20.5). After the object was posted on the Minor Planet Center's PCCP webpage, other CCD astrometrists have commented on the object's cometary appearance. W. H. Ryan (Magdalena Ridge Observatory 2.4-m f/8.9 reflector; Nov. 18.5) writes that R-band images show the coma to be clearly evident (mag 19.6-19.7) with a faint tail at p.a. about 270 deg. H. Sato, Tokyo, Japan notes that sixteen stacked 60-s exposures taken with an iTelescope 0.51-m f/6.8 astrograph at Siding Spring on Nov. 18.57 show the object to be strongly condensed with a round coma 6" in diameter (mag 19.6 as measured within a circular aperture of radius 4".9). The available astrometry, the following preliminary elliptical orbital elements by G. V. Williams, and an ephemeris appear on MPEC 2014-W54. T = 2014 Aug. 5.6304 TT Peri. = 149.7655 e = 0.415372 Node = 247.1085 2000.0 q = 2.565344 AU Incl. = 8.1536 a = 4.387996 AU n = 0.1072271 P = 9.19 years NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2014 CBAT 2014 November 21 (CBET 4018) Daniel W. E. Green