Electronic Telegram No. 3511
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 J3 (McNAUGHT)
     R. H. McNaught reports his discovery of a comet on CCD images taken with
the 0.5-m Uppsala Schmidt telescope at Siding Spring; the discovery images
(tabulated below) show a near-asteroidal object with a 10" coma and a narrow
0'.6 tail in p.a. 150 deg, with a similar appearance (magnitude 17.2) and a
narrow 0'.5 tail in p.a. 145 deg on May 9.37 UT.  Follow-up images by McNaught
on May 10.52 show a 0'.7 tail in p.a. 155 deg.  After posting on the Minor
Planet Center's NEOCP webpage, other CCD astrometrists have commented on the
object's cometary appearance.  Images acquired by E. J. Christensen, S. M.
Larson, and T. Lister with the 1.0-m Las Cumbres Observatory Global Telescope
at Sutherland, South Africa, on May 8.8 show a coma about 7" in size with a
possible tail extending to the southeast.  H. Sato (Tokyo, Japan; remotely
using an iTelescope 0.51-m f/6.8 astrograph at Siding Spring; May 9.6) finds
a strongly condensed with a coma of diameter 15"-18" (with V-band magnitude,
as measured within a circular aperture of radius 9".8, of 17.2) and a tail
65" long toward p.a. 160 degrees on seven stacked 60-s images.

     2013 UT             R.A. (2000) Decl.       Mag.   Observer
     May   8.55176   12 54 53.67   -38 15 12.3   17.4   McNaught
           8.56244   12 54 52.83   -38 14 57.2   17.4     "
           8.57333   12 54 52.01   -38 14 42.0   17.5     "

The available astrometry, the following preliminary parabolic orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2013-J40.

     T = 2013 May  23.8455 TT         Peri. = 336.7797
                                      Node  = 201.2876  2000.0
     q = 4.038172 AU                  Incl. = 117.2606


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 May 11                      (CBET 3511)              Daniel W. E. Green