[IAUC] IAUC 9009: C/2008 Y3; P/2008 X1 = P/2003 F6 [25139-2009/08-R1]

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                                                  Circular No. 9009
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/2008 Y3 (McNAUGHT)
     R. H. McNaught reports his discovery of a comet on CCD images
obtained with the 0.5-m Uppsala Schmidt telescope at Siding Spring
(discovery observation tabulated below), describing the object as
being strongly condensed with a 12" coma and a broad 15" tail in
p.a. 300 deg; the magnitude was determined to be too bright by
perhaps a magnitude due to involvement with a nearby bright star
(when compared with images taken on 2009 Jan. 1.6 UT, when the
comet had similar appearance).  Following posting on the Minor
Planet Center's `NEOCP' webpage, several other CCD astrometrists
have noted the object's cometary appearance.  R. Ligustri (Udine,
Italy) writes that exposures taken remotely with a 0.25-m f/3
reflector near Mayhill, NM, U.S.A., on Jan. 1.4 show a 20" coma but
no nuclear condensation; twelve 120-s co-added images obtained
similarly by E. Guido, G. Sostero, and P. Camilleri on Jan. 1.3
show a compact coma of diameter about 15".  J. E. McGaha (Tucson,
AZ, U.S.A., 0.36-m f/10 reflector, Jan. 1.3) reports that ten
stacked 60-s exposures show a stellar nuclear condensation with a
10"-wide, 74"-long tail in p.a. 309 deg.

     2008 UT             R.A. (2000) Decl.       Mag.
     Dec. 31.64373    8 51 56.50   -21 59 43.3   16.3

The available astrometry, the following preliminary parabolic
orbital elements, and an ephemeris appear on MPEC 2009-A4.

     T = 2009 Nov.  8.502 TT          Peri. = 343.161
                                      Node  = 245.270   2000.0
     q = 1.90426 AU                   Incl. =  33.146


COMET P/2008 X1 = P/2003 F6 (HILL)
     Additional astrometry of comet P/2008 X1 (cf. IAUC 9001)
showed that this comet is of short period (MPECs 2008-Y19, 2008-Y57).
M. Meyer, Limburg, Germany, has identified images of this comet
with a coma diameter of 8" and a 12" tail in p.a. 240 deg on three
NEAT frames from 2003 Mar. 24, and four LONEOS exposures on 2003
Apr. 1; these data are given the designation P/2003 F6 (see CBET
1637).  Astrometry and revised orbital elements (T = 2002 Aug. 19.1;
for epoch 2009 May 9.0 TT, T = 2009 May 7.771 TT, q = 2.36217 AU, e
= 0.33760, Peri. = 4.393 deg, Node = 117.296 deg, i = 18.873 deg,
equinox 2000.0) appear on MPEC 2008-Y60.

                      (C) Copyright 2008 CBAT
2009 January 1                 (9009)            Daniel W. E. Green