[IAUC] IAUC 9074: P/2009 S1; 2007 TY_430 [XXXXX-XXXX/XX-F1]

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                                                  Circular No. 9074
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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COMET P/2009 S1 (GIBBS)
     A. R. Gibbs reports his discovery of a comet on unfiltered CCD
images taken with the Catalina 0.68-m Schmidt telescope (discovery
observation tabulated below); four co-added 30-s exposures show an
8" x 10" compact coma elongated in the direction of the faint 20"
tail (p.a. 270 deg), while four co-added 80-s frames from Sept.
20.43-20.46 UT show the narrow tail to be 45" long.  After posting
on the 'NEOCP' webpage, other CCD astrometrists have commented on
the object's cometary appearance.  E. Guido, Castellammare di
Stabia, Italy, writes that fourteen co-added unfiltered 120-s
exposures taken by G. Sostero and himself remotely using a 0.25-m
reflector near Mayhill, NM, on Sept. 21.4 show a condensed coma
nearly 8" in diameter and a broad tail about 20" long in p.a. 260
deg.  H. Sato (Ota-ku, Tokyo, Japan, also remotely using a 0.25-m
reflector near Mayhill on Sept. 21.4) reports a coma diameter of
12", slightly elongated in p.a. 320 deg.  R. Miles (2.0-m "Faulkes
Telescope North" at Haleakala, Sept. 21.6) measures a 5" tail in
p.a. 277 deg.  L. Buzzi (Varese, Italy, 0.60-m reflector, Sept.
22.1) notes that stacked images totalling 20 min exposure time show
a strong central condensation and a faint tail about 20" long in
p.a. about 270 deg.

     2009 UT             R.A. (2000) Decl.       Mag.   Observer
     Sept.20.38191    3 59 54.60   -10 17 18.3   18.6   Gibbs

     The available astrometry, the following preliminary elliptical
orbital elements, and an ephemeris appear on MPEC 2009-S70.

     T = 2009 July 24.990 TT          Peri. = 221.712
     e = 0.35021                      Node  = 155.805   2000.0
     q = 2.36593 AU                   Incl. =  25.378
       a =  3.64108 AU     n = 0.141860     P =   6.95 years


2007 TY_430
     K. S. Noll, Space Telescope Science Institute (STSI); W. M.
Grundy, Lowell Observatory; S. D. Benecchi, STSI; and H. A. Levison,
Southwest Research Institute, report observations of the known
transneptunian minor-planet binary 2007 TY_430 (cf. MPEC 2008-M38;
IAUC 8962) starting at 2008 Sept. 20.5253 UT with the Wide Field
Planetary Camera 2 on the Hubble Space Telescope.  At the time of
these observations, the binary was separated by 0".248 +/- 0".001
in R.A. and 0".399 +/- 0".001 in Decl., with a difference between
the two components of 0.22 +/- 0.10 magnitude.

                      (C) Copyright 2009 CBAT
2009 September 22              (9074)            Daniel W. E. Green