Electronic Telegram No. 3310
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/2012 US_27 (SIDING SPRING)
     An apparently asteroidal object discovery by R. H. McNaught on CCD iamges
taken with the 0.5-m Uppsala Schmidt telescope at Siding Spring on Oct. 17
(discovery observations tabulated below; given the minor-planet designation
2012 US_27 when announced on MPEC 2012-U49) has now been found by McNaught to
have brightened noticeably and to show cometary appearance; his images taken
with the same telescope on Nov. 21.5 UT show V magnitude 17.5-17.7 and a vague
suggestion of a 10" tail in p.a. 70 deg; the object appears slightly larger
(FWHM = 4".9) than nearby stars of similar brightness (FWHM = 4".1), an
appearance that was confirmed on frames taken by McNaught on Nov. 24.5 (FWHM
5".7 vs. 4".5).  His follow-up images on Nov. 22.5 show again a vague
suggestion of a tail to the east, and he again notices the suggestion of a 10"
tail in p.a. 70 deg on image taken on Nov. 25.5.

     2012 UT             R.A. (2000) Decl.       Mag.   Observer
     Oct. 17.58428    0 48 42.67   -47 27 08.5   19.1   McNaught
          17.59833    0 48 41.18   -47 26 55.1   18.8     "
          17.61253    0 48 39.65   -47 26 41.0   18.8     "
          17.62673    0 48 38.16   -47 26 27.6   18.8     "
          17.76557    0 48 23.77   -47 24 13.9            "

The available astrometry, the following elliptical orbital elements by G. V.
Williams, and an ephemeris appear on MPEC 2012-W47.

     T = 2013 Feb.  8.5770 TT         Peri. =   1.2790
     e = 0.648233                     Node  =  49.2127  2000.0
     q = 1.820649 AU                  Incl. =  39.2887
       a =  5.175727 AU    n = 0.0837042    P =  11.8 years


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2012 CBAT
2012 November 25                 (CBET 3310)              Daniel W. E. Green