[IAUC] IAUC 9072: P/2009 R2 [XXXXX-XXXX/XX-F1]

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                                                  Circular No. 9072
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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COMET P/2009 R2 (PIGOTT-LINEAR-KOWALSKI)
     R. A. Kowalski reports his discovery of a very diffuse comet
of diameter 15"-20" with a faint central condensation and a 29"
elongation in p.a. 280 deg on co-added 60-s CCD exposures taken
with the Catalina 0.68-m Schmidt telescope (discovery observation
tabulated below).  Following posting on the Minor Planet Center's
'NEOCP' webpage, other CCD astrometrists have commented on the
object's cometary appearance.  P. Birtwhistle (Great Shefford,
Berkshire, England, 0.40-m f/6 Schmidt-Cassegrain reflector, Sept.
11.2 UT) notes the object to be diffuse without obvious central
condensation, with diameter 10" and a 15" tail in p.a. 265 deg.
E. Guido and G. Sostero write that ten co-added 120-s unfiltered
exposures (obtained remotely on Sept. 11.4 with a 0.25-m f/3.4
reflector located near Mayhill, NM, U.S.A.) show that this object
is diffuse without a clear central condensation (coma diameter at
least 10", but affected by glare from a nearby field star).  G. Hug
(Scranton, KS, U.S.A., 0.56-m reflector, Sept. 11.43-11.46) finds
the object to be very diffuse with slight condensation.

                    Epoch = 1783 Nov. 10.0 TT
     T = 1783 Nov. 23.1803 TT         Peri. = 354.0531
     e = 0.578766                     Node  =  58.5969  2000.0
     q = 1.458960 AU                  Incl. =  45.7727
       a =  3.463539 AU    n = 0.1529058    P =   6.45 years

     D. Chestnov, Moscow, Russia, has both suggested and
demonstrated that comet P/2009 R2 = P/2003 A1 (cf. IAUCs 8044, 8053,
8430).  The offset of the 2009 discovery observation from the
prediction on MPC 56803 and in the 2008/2009 Comet Handbook is
Delta(R.A.) cos (Decl.) = +15.4 deg, Delta(Decl.) = +8.1 deg; it is
meaningless to indicate a Delta(T) value because the prediction is
strongly influenced by a very close approach to Jupiter (nominally
0.0605 AU on 2006 Sept. 10.4 TT).  The following orbital elements
by B. G. Marsden (from MPEC 2009-R40) linking the 2003 and 2009
observations (with the Jupiter approach as 0.0564 AU on 2006 Sept.
10.3), while only slightly different from the earlier 2003 result,
has a 2009 orbital period that is as much as 0.20 year smaller than
that of the prediction.

                    Epoch = 2009 May   9.0 TT
     T = 2009 May  11.2231 TT         Peri. = 340.9475
     e = 0.529893                     Node  =  54.0711  2000.0
     q = 1.769125 AU                  Incl. =  44.0235
       a =  3.763240 AU    n = 0.1350085    P =   7.30 years

                      (C) Copyright 2009 CBAT
2009 September 11              (9072)            Daniel W. E. Green