Electronic Telegram No. 2782
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/2011 P2 (PANSTARRS)
     Richard Wainscoat, Institute for Astronomy, University of Hawaii, reports
(with Larry Denneau and Henry Hsieh) the discovery of a comet on CCD images
taken by N. Primak, A. Schultz, S. Watters, J. Thiel, and T. Goggia with the
"Pan-STARRS 1" 1.8-m Ritchey-Chretien telescope at Haleakala (discovery
observations tabulated below); Wainscoat noted that the point-spread function
for the object is distinctly soft compared to nearby stars on the discovery
images.  Follow-up images by Wainscoat and Marco Micheli with the Canada-
France-Hawaii telescope (+ r filter) again show the object to have cometary
appearance.  Hsieh writes that images taken with the 2.24-m University of
Hawaii reflector on Aug. 4.5 UT shows a coma but no tail, as do additional
images taken by P. Forshay with the 3.6-m CFHT on Aug. 4.5 (measured by
Wainscoat and Micheli).  After posting on the Minor Planet Center's NEOCP
website, other CCD astrometrists have also commented on the object's
cometary appearance.  T. Lister notes that a coma is visible in his images
taken on Aug. 5.4 with the "Faulkes Telescope North" (2.0-m f/10 Ritchey-
Chretien reflector) at Haleakala.  H. Sato (Tokyo, Japan; remotely using a
0.51-m f/4.5 reflector at the RAS Observatory near Mayhill, NM, U.S.A.;
Aug. 7.24-7.25) finds a coma 8" in diameter with a total V magnitude of
19.4 as measured in an aperture of radius 4".9.  D. J. Tholen also finds a
distinct non-stellar profile of the object in images taken by M. Micheli
and G. T. Elliott on Aug. 7.30-7.45 with the 2.24-m University of Hawaii
reflector.

     2011 UT            R.A. (2000.0) Decl.       Mag.   Observer
     Aug.  3.39419   20 13 21.148  - 9 08 07.82   21.1   Pan-STARRS
           3.41744   20 13 20.619  - 9 08 10.08   20.6     "
           3.42785   20 13 20.354  - 9 08 11.48   20.7     "

The available astrometry, the following elliptical orbital elements
by G. V. Williams, and an ephemeris appear on MPEC 2011-P32.

                    Epoch = 2010 Sept. 1.0 TT
     T = 2010 Sept.18.6260 TT         Peri. =  76.8976
     e = 0.366857                     Node  = 203.9785  2000.0
     q = 6.162715 AU                  Incl. =   8.9926
       a =  9.733533 AU    n = 0.0324562    P =  30.37 years


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 August 7                    (CBET 2782)              Daniel W. E. Green