New Comet: C/2010 S1 (LINEAR)

IAU circular No. 9170, issued on September 24, 2010, announces the discovery by the LINEAR survey of an apparently asteroidal object found to show cometary appearance by other CCD astrometrists. The discovery observation was obtained by LINEAR on Sept. 21.3 UT with a 1.0-m f/2.15 reflector + CCD. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18 magnitude object, designated C/2010 S1 (LINEAR).

We have been able to confirm this object remotely, through the GRAS network, using a scope located in Mayhill (NM): 0.25-m, f/3.4 reflector + CCD.: on Sept. 24.3, co-adding of 18 unfiltered exposures, 120-seconds each, show that this object appears soft compared to nearby field stars of similar brightness with a slight elongation in the east-west direction.

Our confirming image (click on the image for a bigger version):

The preliminary orbit for comet C/2010 S1 (LINEAR) shows perihelion on May 09, 2013, at about 4.4 AU.

According to COCD website, this is the 199th comet discovery for LINEAR.

by Ernesto Guido & Giovanni Sostero

Recovery of P/2001 MD7 (LINEAR) = P/2009 F3 (LINEAR)

IAU Circular No. 9031, issued on 2009 Mar 20, announces the recovery of comet P/2001 MD_7 = COMET P/2009 F3 (LINEAR) by the undersigneds; it was last observed in April 2002.

We picked up this object on 2009 Mar 17, 18 and 20 through a couple of remotely controlled telescopes, located in New Mexico and Australia. The comet appeared as a pale glow, magnitude about 18, nearly 15 arcsec in diameter.

The recovered comet was very close to the ephemerids positions, however its detection has been a little problematic, because it was rather low in the morning sky just before twilight, located in a rich star field in Sgr. We took several nights of observations to locate it, fighting with clouds and moonlight interference.

Here you can see our image of March 22, 2009:

http://tinyurl.com/czgnts

According the orbital elements published by the Minor Planet Center, perihelion will occur in September 2009, with the comet at 1.25 AU from the Sun; at that time P/2009 F3 (LINEAR) will reach about magnitude 12. This object moves along an elliptic orbit in 7.9 years, having a semi-major axis of 3.97 AU, eccentricity of 0.68 and an inclination nearly 13.5 deg.

We thanks the Mayhill-GRAS and Grove Creek-Skylive staff for the kind support they provided us for this tricky recovery.

by Ernesto Guido, Giovanni Sostero & Paul Camilleri