[IAUC] CBET 2134: 20100120 : COMET P/2010 A2 (LINEAR)

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                                                  Electronic Telegram No. 2134
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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COMET P/2010 A2 (LINEAR)
     [Editor's note:  this CBET contains additional information that
could not be published on IAUC 9109 because of printing/space constraints,
due to the great interest in this unusual object.]
     Further to IAUC 9105, the following improved orbital elements (from
MPEC 2010-A78) for this comet are like those of a minor planet in the inner
part of the main belt:

     T = 2009 Nov. 17.248 TT          Peri. = 125.600
     e = 0.13178                      Node  = 321.073   2000.0
     q = 1.97580 AU                   Incl. =   5.099
       a =  2.27570 AU     n = 0.287099     P =   3.43 years

     J. V. Scotti, Lunar and Planetary Laboratory, reports on additional CCD
images of this comet taken by R. S. McMillan with the Spacewatch 1.8-m f/2.7
reflector on Jan. 8.2 and 12.4 UT, in which there was no distinct nuclear
condensation, though the presumed location of the nucleus would be the
eastern end of the elongated coma structure.  On Jan. 8, the coma size was
about 8" x 11", with a sharper edge on the northern boundary, and a long,
narrow tail extended to at least 4'.6 in p.a. 279 deg; a faint spike extended
0'.34 in p.a. 137 deg.  Nine co-added images (effective integration time 1390
s) from Jan. 12 show the width of the elongated coma to be about 11", and its
length to be about 13" in p.a. 297 deg, with a tail at least 4'.8 long in
p.a. 278 deg.
     J. Licandro, Instituto de Astrofisica de Canarias (IAC); G. P. Tozzi,
Istituto Nazionale di Astrofisica, Arcetri; and T. Liimets, Nordic Optical
Telescope (NOT) and Tartu Observatory, report that 5-min R- and V-band
exposures obtained on Jan. 14.945-14.985 UT in very good (0".6) seeing with
the 2.5-m NOT (+ ALFOSC) shows the presence of an asteroidal object 2" east
of (and moving at the same rate as) the uncondensed "dust swarm" of P/2010
A2, which itself is 4' long and about 5" wide (177000 and 3700 km,
respectively, at the comet's distance) in p.a. 277 deg.  Licandro adds that
these observations suggest a connection between the asteroidal object and
the dust swarm; a short-lived event, such as a collision, may have produced
the observed dust ejecta.  Together with A. Cabrera-Lavers and G. Gomez, IAC
and Gran Telescopio Canarias (GTC) Project Office, Licandro further writes
that a series of fifty-four 30-s images obtained on Jan. 16.070-16.133 with
the 10.4-m GTC (+ OSIRIS + g, r, and i Sloan filters) again shows the
asteroidal object about 2" to the east of the comet.
     R. Haver and A. Caradossi, Frasso Sabino, Italy, report that the comet
appears as a tail 1'.8 long in p.a. 278 deg on Jan. 15.95 UT on CCD images
taken with a 0.37-m f/6.8 Cassegrain telescope; on Jan. 16.90, the tail
appeared longer (2'.7 in p.a. 276 deg).  No condensation was visible with
this small an instrument.  L. Buzzi, Varese, Italy, notes a 240" tail in
p.a. 279 deg on stacked CCD images (totally 35 min of exposure; limiting
mag 21.5) taken on Jan. 16.04-16.11 with a 0.60-m f/4.6 reflector.


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

                         (C) Copyright 2010 CBAT
2010 January 20                  (CBET 2134)              Daniel W. E. Green