Electronic Telegram No. 4019 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 C/2014 W2 (PANSTARRS) E. Schunova, R. Wainscoat, and B. Bolin report the discovery of another 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 is bright and clearly non-stellar in appearance, with a broad, low-surface- brightness tail towards the south. 2014 UT R.A. (2000) Decl. Mag. Nov. 17.35307 4 47 27.78 +16 14 15.8 18.8 17.36593 4 47 27.11 +16 14 18.6 18.7 17.37881 4 47 26.43 +16 14 21.5 18.7 17.39168 4 47 25.76 +16 14 24.4 18.7 Wainscoat and M. Micheli report that three 60-s r-band follow-up exposures taken by Wainscoat and A. Draginda with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea on Nov. 18.5 UT show the comet to be diffuse with a light halo around a stellar core (magnitude 18.6-18.8) with a broad, short, low-surface-brightness tail extending toward position angle 200 degrees. Bolin and Wainscoat add that three additional 45-s w-band exposures obtained with the Pan-STARRS1 telescope on Nov. 19.4 show the object as having a clearly diffuse, non-stellar appearance with a broad, diffuse tail in p.a. 200 degrees (magnitude given as 17.7-18.0). After the object was posted on the Minor Planet Center's PCCP webpage, other CCD astrometrists have commented on the object's cometary appearance. E. Guido, M. Nicolini, and N. Howes stacked ten 120-s unfiltered exposures obtained remotely with an iTelescope 0.43-m f/6.8 reflector at Nerpio, Spain, on Nov. 18.93-18.95 that show a diffuse coma about 6" in diameter (red mag 17.6-17.7). G. Galli (Pogliano Milanese, Italy, 0.28-m Schmidt-Cassegrain reflector, Nov. 19.05-19.06) reports that stacked images show a round coma 8" wide of mag 17.5-17.9. R. Ligustri, Udine, Italy, reports that 180-s exposures taken remotely with a 0.43-m f/6.7 reflector on Nov. 18.66 UT show a prominent V-shaped coma of red mag 16.9-17.2 and size about 20", extended toward p.a. 220 deg. W. H. Ryan (Magdalena Ridge Observatory 2.4-m f/8.9 reflector, Nov. 18.5) finds the coma to be clearly evident, with R-band images giving mag 17.2 and a faint tail in p.a. about 190 deg. H. Sato (Tokyo, Japan; remotely with an iTelescope 0.51-m f/6.8 astrograph + luminance filter near Mayhill, NM, USA; Nov. 18.13-18.14) finds the comet to be strongly condensed with a round coma 12" in diameter with w-band mag 17.5 as measured within a circular aperture of radius 6".5. L. Buzzi (Varese, Italy; 0.60-m f/4.64 reflector; Nov. 19.15-19.17) writes that stacked images reveal a softer aspect for the comet with respect to nearby stars, with a round and compact coma 15" wide; no tail is clearly seen, but the edge of the coma is clearly softer towards the southeast. The available astrometry (including pre-discovery Catalina Sky Survey observations, identified by T. Spahr, on Oct. 26.3, when the comet was at mag 17.7-18.0, and on Nov. 16.3 at mag 17.3-17.5), the following elliptical orbital elements by G. V. Williams, and an ephemeris appear on MPEC 2014-W55. Epoch = 2016 Apr. 2.0 TT T = 2016 Mar. 19.5528 TT Peri. = 85.9051 e = 0.954038 Node = 70.0292 2000.0 q = 2.674610 AU Incl. = 81.0407 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 4019) Daniel W. E. Green