Electronic Telegram No. 3775
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 Y2 (PANSTARRS)
     Bryce Bolin, Peter Veres, and Richard Wainscoat report the discovery of a
comet that has a diffuse, non-stellar appearance in two 43-s g'-band exposures
and in two 40s r'-band exposures taken with the Pan-STARRS1 telescope on
Haleakala on 2013 Dec. 30 (discovery observations tabulated below).  Morphology
measurements show that the point-spread function of the object is extended
relative to adjacent stars in each image.  In a stacked image, there is no sign
of a tail.  Follow-up observations obtained by R. J. Wainscoat and A. Draginda
with the 3.6-m Canada-France-Hawaii Telescope on 2014 Jan. 3.4 UT (measured by
M. Micheli and Wainscoat) show a coma with full-width-at-half-maximum of about
1".85 in 1".5 seeing; the r-band exposures yield mag 17.8-17.9.

     2013 UT             R.A. (2000) Decl.       Mag.
     Dec. 30.51260    8 30 36.75   -18 42 57.4   18.4
          30.52491    8 30 36.45   -18 43 07.9   18.4
          30.53745    8 30 36.15   -18 43 18.8   18.0
          30.54892    8 30 35.87   -18 43 28.8   18.0

     After posting on the Minor Planet Center's PCCP webpage, other CCD
astrometrists have also commented on the object's cometary appearance.  Thirty
co-added 20-s images taken by T. Linder and R. Holmes with a 0.41-m f/11
Ritchey-Chretien telescope at Cerro Tololo on Dec. 31.2 show a 0".4 coma with
no apparent tail.  H. Sato (Tokyo, Japan; remotely with an iTelescope 0.51-m
f/6.8 astrograph located near Mayhill, NM, U.S.A.; eight 60-s stacked images
on Dec. 31.37) finds the comet strongly condensed with a round coma of diameter
12" with no obvious tail; the luminance-filter magnitude as measured within a
circular aperture of radius 8".2 was 17.4.  R. Ligustri (Udine, Italy; remotely
with an iTelescope 0.43-m f/6.8 reflector at Siding Spring; eight 120-s images
on Dec. 31.7) finds a round coma of diameter about 12"-15".
     The available astrometry, the following parabolic orbital elements by
G. V. Williams, and an ephemeris appear on MPEC 2014-A59.

     T = 2014 June 13.9869 TT         Peri. = 307.7040
                                      Node  = 244.1298  2000.0
     q = 1.940942 AU                  Incl. =  29.6672


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 January 10                  (CBET 3775)              Daniel W. E. Green