[IAUC] CBET 2879: 20111031 : COMET P/2011 UA134 (SPACEWATCH-PANSTARRS)

Dom Oct 30 19:24:42 ART 2011

                                                  Electronic Telegram No. 2879
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 en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network

COMET P/2011 UA134 (SPACEWATCH-PANSTARRS)
     Larry Denneau, Richard Wainscoat, and Henry Hsieh, Institute for
Astronomy, University of Hawaii, report the discovery of a comet on CCD images
taken with the "Pan-STARRS 1" 1.8-m Ritchey-Chretien telescope at Haleakala
(discovery observations tabulated below), noting that the point-spread
function (PSF) of the object's image is distinctly soft when compared to
those of nearby stars (and shows slight excesses compared to expected stellar
PSFs).  Six images were obtained using the Canada-France-Hawaii Telescope on
Oct. 26 UT by Marco Micheli and Richard Wainscoat (queue observer Adam
Draginda); Micheli writes that the object appears slightly extended, with a
stacked image showing a 10" in p.a. about 255 deg (which is also weakly
visible in each single exposure).  After posting on the Minor Planet Center's
NEOCP webpage, L. Buzzi (Varese, Italy, 0.60-m f/4.64 reflector) reports that
stacked images (45 min total exposure) taken in good seeing on Oct. 29.14-29.16
show a compact coma 8" wide (with FWHM about 25 percent larger than stars
nearby) with total red mag 19.8 and a tail at least 15" long in p.a. around
260 deg.  T. Vorobjov, L. Buzzi, and S. Foglia measured images taken by
R. Holmes (Ashmore, IL, USA, 0.61-m f/4 astrograph) on Oct. 30.2-30.3; stacked
exposures reveal an elongated 10" x 8" coma with a faint tail 10" long in p.a.
270 deg.
     When the first night of observations were received by the Minor Planet
Center, they were automatically linked with a one-night object observed
the previous night by the Spacewatch project, and based on those first two
nights, the MPC automatically designated the object as 2011 UA134 (cf. MPS
396661).

     2011 UT             R.A. (2000) Decl.       Mag.   Observer
     Oct. 24.42686    4 43 44.60   +26 30 44.9   20.4   Spacewatch
          24.44466    4 43 44.87   +26 30 55.5   20.4     "
          24.46591    4 43 45.08   +26 31 06.8   20.0     "
          25.42562    4 43 59.82   +26 40 08.0   21.4   Pan-STARRS
          25.44013    4 43 59.98   +26 40 16.3   21.2     "
          25.45457    4 44 00.14   +26 40 24.6   21.2     "
          25.46901    4 44 00.31   +26 40 32.9   21.3     "

The available astrometry, the following elliptical orbital elements by G. V.
Williams, and an ephemeris appear on MPEC 2011-U108.

     T = 2011 Dec.  4.9255 TT         Peri. =  31.4910
     e = 0.627916                     Node  =  40.4814  2000.0
     q = 2.046893 AU                  Incl. =  10.4512
       a =  5.501157 AU    n = 0.0763876    P =  12.90 years

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

                         (C) Copyright 2011 CBAT
2011 October 31                  (CBET 2879)              Daniel W. E. Green