IAUC nr.9218, issued on 2011, June 25, announces the discovery of a new comet (discovery magnitude 18.6) by the LINEAR survey with a 1.0-m f/2.15 reflector + CCD, on images obtained on 2011, June 22.4. The new comet has been designated C/2011 M1 (LINEAR)
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 15 unfiltered exposures, 60-sec each, obtained remotely on 2011, June 23.4 from the Tzec Maun Observatory (near Mayhill, NM) through a 0.35-m f/3.8 reflector + CCD, shows that this object is a comet: coma nearly 30" in diameter, with a weak central condensation. Total magnitude (unfiltered CCD) m1= 16.5 We suspect the presence of an extension, or a faint tail, nearly 40" long in PA 240, however the visibility of this detail is hampered by the moonlight.
Our confirming image (click for a bigger version):
M.P.E.C. 2011-M37 assignes the following preliminary orbital elements to comet C/2011 M1: T 2011 Sept. 7.59; e= 1.0; Peri. = 119.04; q = 0.90 AU; Incl. = 69.97
This is the 204th comet discovery for LINEAR survey!
by Giovanni Sostero & Ernesto Guido