Electronic Telegram No. 2249
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbat@iau.org; cbatiau@eps.harvard.edu
URL
http://www.cfa.harvard.edu/iau/cbat.htmlCOMET P/2010 H2
Observations of an unusually bright asteroidal object (discovery
observation below), only 15 deg from opposition, were reported to the Minor
Planet Center yesterday by J. Vales, observing with the 0.60-m f/3.3
Deltagraph at Crni Vrh, Slovenia. The numerous follow-up observations
reported after the discovery was announced on the NEOCP soon made it clear
that the object was some 2.0-2.5 AU from the earth and therefore of absolute
magnitude H = 8-9. It was also soon clear that there were no recent
observations of the object in the MPC files, and R. A. Kowalski has confirmed
that it was not present (down to magnitude V = 20) in frames of the relevant
region obtained by the Catalina Sky Survey as recently as Apr. 15.4 UT.
Several observers, beginning with W. Ryan on Apr. 16.2 at Magdalena Ridge
(2.4-m f/8.9 reflector) and E. Guido and G. Sostero on Apr. 16.4 at Mayhill,
NM (0.25-m f/3.4 reflector), have indicated that the new object has an FWHM
consistently wider (by perhaps 10%) than nearby field stars of similar
brightness. R. Miles reports that observations on Apr. 16.5 at the Faulkes
Telescope South (2.0-m f/10.0 Ritchey-Chretien) gave colors g'-r' = 0.503,
r'-i' = 0.113 and i'-z = 0.116, suggestive of a cometary dust coma. A. Maury,
San Pedro de Atacama, Chile, reports the detection of a faint coma on a
60-min exposure (0.36-m f/2 reflector) centered on Apr. 17.3; and K. Kadota,
Ageo, Saitama, Japan, remarks that, although the object appears starlike,
16 stacked 60-s exposures (0.25-m f/5.0 reflector) on Apr. 17.6 indicate a
possible faint coma of diameter 1'.5.
2010 UT R.A. (2000) Decl. Mag. Observer
Apr. 16.00831 13 39 25.17 +04 45 49.5 12.6 Vales
The astrometry obtained so far (226 observations), the following
still-very-preliminary elliptical orbital elements and an ephemeris are given
on MPEC 2010-H12. While necessarily uncertain, this and other similar
orbital solutions suggest that the object passed 1.2 AU (or perhaps
significantly less) from Jupiter in 1976.
T = 2010 May 21.605 TT Peri. = 144.469
e = 0.20730 Node = 64.548 2000.0
q = 3.07064 AU Incl. = 14.115
a = 3.87366 AU, n = 0.129277 deg/day, P = 7.62 years
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2010 CBAT
2010 April 17 (CBET 2249) Brian G. Marsden
