IAUC nr.9210, issued on 2011, May 31, announced the discovery of a new comet (discovery magnitude 19.1) by A. Boattini through the Mt. Lemmon 1.5-m reflector + CCD, on images obtained on 2011, May 28.3 After posting on the Minor Planet Center's NEOCP webpage, this object was identified with an object reported as apparently asteroidal by the Spacewatch survey on May 8 and 12 and previously given the designation 2011 JB_15.
The new comet has been designated P/2011 JB_15 (SPACEWATCH-BOATTINI).
After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP. Stacking of 20 unfiltered exposures, 180-sec each, obtained remotely on 2011, May 30.3 from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD, shows that this object is a comet: coma nearly 8-arcsec in diameter with a very weak central condensation.
Our confirming image (click for a bigger version):
M.P.E.C. 2011-K56 assignes the following preliminary orbital elements to comet P/2011 JB_15: T 2012 Jan. 18.13; e= 0.32; Peri. = 110.46; q = 5.03 AU; Incl. = 19.15
According to COCD website this is the 49th comet discovery for Spacewatch survey and the 17th for Andrea Boattini.
by Ernesto Guido & Giovanni Sostero