Electronic Telegram No. 3417
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 C2 (TENAGRA)
     An apparently asteroidal object reported by P. R. Holvorcem (working with
M. Schwartz) from CCD images taken on Feb. 14 with a 0.41-m f/3.75 astrograph
at Schwartz's Tenagra Observatory (near Nogales, AZ, U.S.A.; discovery
observations tabulted below), and posted on the Minor Planet Center's NEOCP
webpage, was found by various CCD astrometrists on subsequent dates (including
by the discoverers) to show cometary appearance.  Twelve co-added 150-s
unfiltered exposures taken by Holvorcem and Schwartz between Feb. 15.25 and
15.28 UT with the Tenagra II 0.81-m telescope in good seeing (FWHM 2".6) show
a central condensation about 6" in diameter with an extended, diffuse coma of
diameter about 25"; their additional three 240-s co-added exposures taken
between Feb. 17.34 and 17.39 with the Tenagra III 0.41-m astrograph show a
coma with diameter of about 15" in average seeing (FWHM 3".5).  H. Sato
(Tokyo, Japan; remotely using an iTelescope.net 0.51-m f/6.8 astrograph near
Mayhill, NM, U.S.A.) reports that V-band exposures show a starlike nuclear
condensation of mag 19.6 and a faint outer coma of diameter 25" with total
magnitude of 18.3.  Erik Bryssinck (Kruibeke, Belgium; remotely using an
iTelescope.net 0.43-m f/6.8 reflector + luminance filter near Mayhill;
stacked images taken around Feb. 16.3) finds a circular 14" coma with a
diffuse condensation at the center of the coma.  B. L. Stevens (Las Cruces,
NM, U.S.A.; 0.3-m Schmidt-Cassegrain reflector; Feb. 17.3) measured a wide
tail 18" long in p.a. 305 degrees.

     2013 UT             R.A. (2000) Decl.       Mag.
     Feb. 14.24315   10 10 29.54   -14 03 41.3   19.0
          14.25763   10 10 29.37   -14 03 41.4   19.2
          14.27211   10 10 29.09   -14 03 40.9   19.1

The available astrometry, the following preliminary elliptical orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2013-D22.

     T = 2013 May   5.3684 TT         Peri. = 271.8319
     e = 0.268104                     Node  = 249.5976  2000.0
     q = 9.951589 AU                  Incl. =  21.3923
       a = 13.596994 AU    n = 0.0196580    P =  50.1 years


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 February 17                 (CBET 3417)              Daniel W. E. Green