[IAUC] IAUC 8703: C/2006 GZ_2; 73P; P/2006 G1 [25139-2006/04-R1]

Vie Jun 22 17:07:31 ART 2007

                                                  Circular No. 8703
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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COMET C/2006 GZ_2 (SPACEWATCH)
     An apparently asteroidal object discovered by Spacewatch
(discovery observation below) was reported already on Apr. 7.9 UT
to be slightly diffuse in follow-up images obtained in strong
moonlight by J. Ticha and M. Tichy with the 1.06-m telescope at
Klet.  With no other reports on physical appearance available, the
object was announced as 2006 GZ_2 on Apr. 10 (MPEC 2006-G38; also
MPS 168881), but on the following day, J. Montani reported that his
inspection of the Spacewatch images from Apr. 7.2, 8.2, and 9.2 all
show the object to have a coma of diameter 5"-6" and no tail.  R. S.
McMillan adds that Spacewatch images taken by T. H. Bressi on Apr.
18.4 also show the object to be diffuse with a 4"-5" coma.

     2006 UT             R.A. (2000) Decl.       Mag.
     Apr.  7.18152   12 53 41.82   - 0 16 27.9   20.1

More recent astrometry, the following parabolic orbital elements,
and an ephemeris appear on MPEC 2006-H10.

     T = 2006 Aug. 22.050 TT          Peri. = 191.508
                                      Node  = 355.320   2000.0
     q = 3.30214 AU                   Incl. = 168.683

COMET 73P/SCHWASSMANN-WACHMANN
     Futher to IAUC 8701, numerous additional components to 73P
have been observed on three or more nights and thus given
designations ('T'-'Z', and 'AA'-'AM', although component 'Y' has
only two nights of astrometry so far) and first announced on MPECs
2006-G10 and 2006-H03.

COMET P/2006 G1 (McNAUGHT)
     Additional observations published on MPEC 2006-G43 and MPC
56610 show that this comet (cf. IAUC 8699) is indeed of short
period, with the following improved orbital elements:

     T = 2006 Aug. 20.7210 TT         Peri. = 314.8793
     e = 0.455391                     Node  = 299.0576  2000.0
     q = 2.621261 AU                  Incl. =  18.5516
       a =  4.813108 AU    n = 0.0933395    P =  10.56 years

                      (C) Copyright 2006 CBAT
2006 April 19                  (8703)            Daniel W. E. Green