Electronic Telegram No. 3683
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 U2 (HOLVORCEM)
     Paulo Holvorcem reports his discovery of a comet in three unfiltered
150-s exposures taken with the 0.41-m Tenagra III astrograph (discovery
astrometry tabulated below) in strong moonlight.  Three follow-up co-added
300-s unfiltered exposures taken with the 0.81-m Tenagra II telescope between
Oct. 24.46 and 24.50 UT in good seeing (FWHM 2".6) showed a coma with diameter
6" and a 6"-long tail toward p.a. 231 deg.  Holvorcem co-added three additional
300-s unfiltered exposures taken with the 0.81-m Tenagra II telescope between
Oct. 26.43 and 26.46 in 3".0 seeing that show a 6" coma with a 6"-long tail
toward p.a. 243 deg.  After the object was posted on the Minor Planet Center's
new PCCP webpage (see CBET 3682), other CCD astrometrists have also commented
on the object's cometary appearance.  H. Sato (Tokyo, Japan; remotely using a
0.51-m f/6.8 astrograph + luminance filter at the iTelescope site near Mayhill,
NM, U.S.A., on Oct. 25.25) found a strongly condensed coma of diameter 10" and
magnitude 18.8 as measured within a circular aperure radius of 7".6.  L. Buzzi
reports that images taken with the 2.0-m "Faulkes Telescope North" at
Haleakala on Oct. 25.5 by a team of nine observers and measurers show a central
condensation surrounded by a diffuse coma at least 5" wide, with no apparent
tail.  R. Ligustri (Talmassons, Udine, Italy; remotely with an iTelescope
0.43-m f/4.5 reflector near Mayhill) notes a noticeable coma about 20" in size
and of mag 18.1-18.3, apparently elongated toward p.a. 220 deg on images taken
on Oct. 27.2.  S. Foglia reports that thirty stacked 30-s images taken by R.
Holmes (Ashmore, IL, USA) with a 0.61-m f/4 astrograph on Oct. 29.2 shows a
round coma 10" in diameter and a narrow tail 15" long in p.a. 245 deg.

     2013 UT             R.A. (2000) Decl.       Mag.   Observer
     Oct. 23.41722    4 15 52.46   +66 13 35.7   18.7   Holvercem
          23.43825    4 15 51.62   +66 13 42.0            "
          23.45837    4 15 50.96   +66 13 50.9            "
          24.46346    4 15 15.17   +66 20 25.3   18.8     "
          24.48294    4 15 14.43   +66 20 32.7   18.7     "
          24.50253    4 15 13.72   +66 20 40.1   18.8     "

The available astrometry, the following parabolic orbital elements by G. V.
Williams, and an ephemeris appear on MPEC 2013-U84.

     T = 2014 Sept.22.6252 TT         Peri. =  99.6403
                                      Node  =   9.7723  2000.0
     q = 5.429091 AU                  Incl. =  44.0139


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

                         (C) Copyright 2013 CBAT
2013 October 30                  (CBET 3683)              Daniel W. E. Green