[IAUC] CBET 2926: 20111130 : COMET P/2010 UH55 (SPACEWATCH)

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                                                  Electronic Telegram No. 2926
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET P/2010 UH55 (SPACEWATCH)
     [Editor's note:  This text replaces that on CBET 2923 (designation
year correction, title only).]
     An apparently asteroidal reported by the Spacewatch survey (discovery
observations tabulated below), and designated 2010 UH55 by the Minor Planet
Center last year, has been found to show cometary activity.  H. Sato (Tokyo,
Japan) first reported the appearance of a condensed coma of size 6"-8" last
year; his CCD images taken remotely on 2010 Nov. 17.4 UT taken with a 0.50-m
f/6.8 reflector at the RAS Observatory near Mayhill, NM, U.S.A., suggest that
the west side of the object appeared soft, with a hint of tail 12" long.
Sato's report of cometary appearance remained unconfirmed until the past
month, when he again found the object on 2011 Nov. 3.5 to be moderately
condensed a faint coma of diameter 40" (and mag 18.8 within a circular
aperture of radius 19".7) with a 55" tail in p.a. 290 degrees with a 0.51-m
f/4.5 reflector at the same site.
     Luca Buzzi (Varese, Italy; 0.38-m f/6.8 relector) found a compact coma
8" wide that was faintly elongated out to 10"-15" in p.a. around 290 deg on
stacked images obtained on Nov. 15.15-15.17 in good seeing but with moonlight
interference.  D. Chestnov and A. Novichonok report that 300-s unfiltered CCD
images taken on Nov. 25.09 by V. Gerke with the 0.40-m telescope at the TAU
Station of Ka-Dar Observatory (near Nizhny Arkhyz, North Caucasus, Russia)
show that 2010 UH55 has a small coma of total mag 18.7 and a 0'.2 tail in p.a.
about 295 deg; six stacked 240-s images taken on Nov. 28.03 show the same
morphology except measuring the tail to be in p.a. 319 deg.  G. Sostero, K.
Rochowicz, N. Howes, and E. Guido write that five stacked 40-s R-band images
taken remotely with the 2.0-m f/10 "Faulkes Telescope North" at Haleakala on
Nov. 28.6 show a diffuse coma about 9" in diameter (mag 18.2-18.3) with a
faint, broad tail nearly 20" long toward the west-northwest.

     2010 UT             R.A. (2000) Decl.       Mag.   Observer
     Oct. 29.21706    3 31 53.06   +20 24 43.4   19.4   Spacewatch
          29.23481    3 31 52.58   +20 24 38.8   19.6     "
          29.25255    3 31 52.08   +20 24 34.7   19.7     "

S. Nakano notes that 2010 UH55 passed 0.58 AU from Jupiter on 1946 June 5
and 0.42 AU from Saturn on 1900 Jan. 1 UT.  Revised orbital elements by
G. V. Williams from MPEC 2011-W82:

                    Epoch = 2011 Aug. 27.0 TT
     T = 2011 May  10.39701 TT        Peri. = 221.62832
     e = 0.5752275                    Node  = 235.26362 2000.0
     q = 2.7680070 AU                 Incl. =   8.66233
       a =  6.5164457 AU   n = 0.05924994   P =  16.64 years


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 November 30                 (CBET 2926)              Daniel W. E. Green