Electronic Telegram No. 4064
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/2015 B1 (PANSTARRS)
     R. Weryk and R. Wainscoat report that an apparently asteroidal object
discovered in four i-band exposures with the 1.8-m Pan-STARRS1 telescope at
Haleakala on Jan. 29 UT (discovery observations tabulated below) was
accidentally rediscovered two nights later with the same telescope and then
noted on the Jan. 29 images as showing cometary appearance:  FHWM of adjacent
stars being 1".1, while the FWHM of the comet is approximately 2".5, with a
stacked image showing evidence of a tail extending for approximately 3"
towards p.a. approximately 250 degrees; the appearance on Jan. 31 was similar.
Pre-discovery sets of four w-band 45-s Pan-STARRS1 exposures showing the comet
on Jan. 19.5 and 21.6 were subsequently found by M. Micheli and Wainscoat, the
object showing a tail about 5" long in p.a. about 310 deg.

     2015 UT             R.A. (2000) Decl.       Mag.
     Jan. 19.52597   11 30 26.98   + 7 15 41.5   19.8
          19.53948   11 30 26.86   + 7 15 41.2   19.8
          19.55301   11 30 26.72   + 7 15 41.6   19.7
          19.56661   11 30 26.59   + 7 15 41.1   19.7
          21.55830   11 30 07.66   + 7 15 24.7   19.8
          21.56986   11 30 07.52   + 7 15 24.4   19.7
          21.58141   11 30 07.38   + 7 15 23.9   19.8
          21.59300   11 30 07.27   + 7 15 24.4   19.9
          29.51882   11 28 28.25   + 7 16 13.4   20.5
          29.53021   11 28 28.06   + 7 16 13.4   20.5
          29.54157   11 28 27.91   + 7 16 13.4   20.3
          29.55296   11 28 27.69   + 7 16 13.6   20.4
          31.51971   11 27 57.61   + 7 16 52.3   20.5
          31.53147   11 27 57.41   + 7 16 52.5   20.5
          31.54323   11 27 57.23   + 7 16 53.0   20.4
          31.55499   11 27 57.00   + 7 16 53.1   20.6

The following preliminary parabolic orbital elements by G. V. Williams with an
ephemeris appear on MPEC 2015-C12.

     T = 2016 Sept.25.4429 TT         Peri. = 250.8133
                                      Node  = 352.2101  2000.0
     q = 3.720716 AU                  Incl. =  20.9078


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2015 CBAT
2015 February 4                  (CBET 4064)              Daniel W. E. Green