[IAUC] IAUC 9007: C/2008 Y1; P/2008 X4 [25139-2009/08-R1]

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                                                  Circular No. 9007
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 Y1 (BOATTINI)
     A. Boattini reports his discovery of moderately-condensed
comet of size 10" and with a tail about 20" long in p.a. 70 deg on
images taken with the Catalina Sky Survey 0.68-m Schmidt telescope
(discovery observation tabulated below).  Following posting on the
Minor Planet Center's 'NEOCP' webpage, other astrometric CCD
observers have also noted the object's cometary appearance.  F.
Hormuth (Calar Alto, Spain, 1.23-m reflector) reports a 4" coma
with a 15" tail in p.a. about 80 deg in five stacked 75-s
unfiltered exposures from Dec. 22.76-22.77 UT; a stacked 15-min
exposure from 24 hr later reveals a coma diameter of 8" and a tail
30" long in p.a. about 70 deg.  R. Ligustri (Talmassons, Udine,
Italy, 0.35-m f/5 reflector) reports that twenty 120-s exposures on
Dec. 23.7 shows an 18" tail in p.a. 51 deg.  G. Masi (Ceccano,
Italy, Dec. 24.74) finds the object to be diffuse with an extension
extending to about 5".  L. Buzzi (Varese, Italy, 0.60-m f/4.6
reflector, Dec. 24.74-24.76) notes that stacked exposures show a
compact coma 10" wide with a fan-like tail 15"-20" long centered at
p.a. about 55-60 deg, adding that a knot or condensation in the
tail appears 10" from the nuclear condensation in p.a. 52 deg; 25-
min stacked exposures from Dec. 25.8 show a 10" coma elongated for
15" in p.a. about 65 deg, again suggesting that other knots or
condensations appear to be following the main component.  G. Hug
(Scranton, KS, U.S.A., 0.56-m reflector, Dec. 25.1) finds the
object to be somewhat diffuse.

     2008 UT             R.A. (2000) Decl.       Mag.
     Dec. 22.08726   22 13 51.56   - 2 54 17.3   17.9

The available astrometry, the following preliminary parabolic
orbital elements, and an ephemeris appear on MPEC 2008-Y53.

     T = 2009 Feb. 16.808 TT          Peri. = 154.819
                                      Node  = 255.500   2000.0
     q = 1.40724 AU                   Incl. =   8.959


COMET P/2008 X4 (CHRISTENSEN)
     J. N. Marcus, St. Louis, MO, U.S.A., suggested last week that
comet P/2008 X4 would be a good candidate for enhanced brightness
due to significant forward-scattering geometry as its solar
elongation approaches zero now (minimum elongation = 0.4 deg on
Dec. 23.64 TT) -- perhaps reaching total mag about 4 -- and he and
K. Battams note that the comet is visible clearly in SOHO/LASCO
data from the C3 and C2 coronographs.

                      (C) Copyright 2008 CBAT
2008 December 25               (9007)            Daniel W. E. Green