Electronic Telegram No. 2256
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
 Sciences; Harvard University; 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbat@iau.org; cbatiau@eps.harvard.edu
URL http://www.cfa.harvard.edu/iau/cbat.html


COMET C/2010 H3 (SOHO)
     Further to IAUC 9116, measurements by K. Battams and orbital solutions
by the undersigned for a SOHO comet detected by J. Ruan are given on MPEC
2010-H37.  This Marsden-group comet was at perihelion on Apr. 19.9 TT, 11.6
days earlier than the prediction in the ICQ 2009/2010 Comet Handbook from the
assumption (MPEC 2004-X73) that C/1999 J6 = C/2004 V9.

 Comet       2010 UT       R.A.(2000)Decl.   Inst.  F    MPEC
 C/2010 H3   Apr. 18.938   01 47.2  +09 22   C2/3   JR   2010-H37

     M. Knight, Lowell Observatory, presents plots of the photometry of
all three objects at http://www.lowell.edu/users/knight/research/1999j6.html
and from the similarity suggests that the three are almost certainly one
and the same object.  The uncalibrated data show C/2010 H3 brightening
from mag 9.0-9.5 at discovery to mag 5.5 at the final C2 observation on
Apr. 19.56 UT, while in C3 the brightness was rather steady at mag 7 from
Apr. 19.61 to Apr. 20.2, fading to mag 8-9 by Apr. 20.7.  Knight adds that
these three comets are brighter than any other observed Marsden-group members
(see http://www.lowell.edu/users/knight/docs/dissertation.pdf).


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 April 21                    (CBET 2256)              Brian G. Marsden