Electronic Telegram No. 3630 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/2013 P3 (PALOMAR) Adam Waszczak, California Institute of Technology, reports the discovery of a comet in five 60-s r-band exposures taken with the 1.2-m f/2.4 Oschin Schmidt telescope as part of the "Palomar Transient Factory" (PTF) survey on Aug. 9 and Aug. 10 UT (discovery observations tabulated below); the object's nuclear condensation appears point-like (in 2" seeing and 1".01/pixel resolution) with a faint tail about 15" long in p.a. 330 deg; Waszczak's report of it appearing cometary arrived after posting on the Minor Planet Center's NEOCP webpage and after other CCD astrometrists also were reporting on the object's cometary appearance. T. Lister (Las Cumbres Observatory Global Telescope Network) obtained images on Aug. 11.4 UT with the 1.0-m f/8 Ritchey-Chretien telescope at McDonald Observatory that show a coma about 6" across of red mag 19.4-19.5 and a faint tail about 19" long extending to the northwest; twelve stacked 300-s follow-up frames taken on Aug. 12.4 in 1".2 seeing show a coma about 5" across and a 20" tail. Seventy-nine co-added 60-s exposures taken by P. Bacci with a 0.60-m f/4 reflector at San Marcello Pistoiese, Italy, on Aug. 12.02-12.07 show a coma diameter of 7".8 (red mag 19.1-19.5) and a tail 34" long in p.a. 327 degrees. Nine stacked 60-s exposures taken by H. Sato (Tokyo, Japan) with a 0.32-m f/8 astrograph of the RAS Observatory near Nerpio, Spain, on Aug. 12.1 show a strongly condensed coma 6"-8" in diameter and a hint of tail 10" long toward p.a. 310 degrees; the luminance-filtered magnitude as measured within a circular aperture of radius 5".8 was 19.5. Fifteen stacked 120-s exposures taken by C. Jacques, E. Pimentel, and J. Barros with a 0.30-m f/3 reflector at Oliveira, Brazil, on Aug. 12.1 show a condensed coma of diameter 18". Images taken on Aug. 13.0 by D. Caporicci, G. Ierman, and E. Pettarin with a 0.61-m f/4 reflector at Farra d'Isonzo, Italy, show a tail 25" long in p.a. 323 deg. Luca Buzzi, Varese, Italy, writes that a stack of images totalling 30 minutes of exposure time in good seeing with a 0.60-m f/4.64 reflector reveals a coma 15" wide of red mag 18.8 with a fan-shaped tail 23" long centered at p.a. 337 deg. Sixty stacked 22-s exposures taken with a 0.61-m f/4 astrograph by R. Holmes (Ashmore, IL, USA) on Aug. 14.4 (measured by T. Vorobjov, L. Buzzi, and S. Foglia) show that the comet's image appears soft with respect to nearby stars. 2013 UT R.A. (2000) Decl. Mag. Aug. 9.43034 23 24 43.02 +29 10 31.4 18.9 9.46832 23 24 42.25 +29 10 25.0 19.2 10.36994 23 24 24.90 +29 07 50.2 19.2 10.43030 23 24 23.70 +29 07 39.9 19.2 10.46666 23 24 22.98 +29 07 33.6 19.2 11.36885 23 24 05.33 +29 04 53.8 19.0 The available astrometry (including prediscovery PTF observations from Aug. 8), the following preliminary parabolic orbital elements by G. V. Williams, and an ephemeris appear on MPEC 2013-Q02. T = 2011 June 25.9716 TT Peri. = 101.0035 Node = 181.3367 2000.0 q = 6.931142 AU Incl. = 85.5367 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 August 16 (CBET 3630) Daniel W. E. Green