Tuesday, April 7, 2009

New Comet 2009 F6

IAUC Circular No. 9034, issued on 2009, April 6, announces the discovery by R. D. Matson of a new comet from analysis of ultraviolet SWAN-SOHO images obtained on 2009, Mar. 29, 31, Apr. 1, 3, and 4.

We undertaken a first try to locate this object from the private observatory of one of us on (about) Apr. 6.1; however we were unsuccessfull, due to some hardware problems with the telescope.

Afterwards we were able to confirm the existence of this comet remotely, through the GRAS network, using a scope located in Mayhill (NM): on 2009, April 6.5, co-adding of 10 unfiltered exposures, 60 seconds each, obtained by means of a 0.25-m, f/3.4 reflector + CCD, shown a diffuse coma about 2.5 arcmin in diameter, with a sharp central condensation about 20 arcsec in diameter. The magnitude of the central condensation was measured to be at about 14 (unfiltered CCD), while the total magnitude m1 has ben established to be about 11 (unfiltered CCD).

Stacking a total of 20 minutes exposure time, through equalization of the histogram, we can trace a coma diameter of nearly 5 arcmin; image enhancing techniques (azimuthal median subtraction and 1/r theoretical coma subtraction) show the presence of a short extension toward North-East, emanating from the central condensation (hint of a tail, or elongation of the coma?).

Our image is available here:


At the time of this writing, no orbital elements of this comet has been published by the Minor Planet Center. A preliminary calculation, performed by the undersigneds running through FindOrb the observation currently available at the the NEO-CP webpage, gives the following (approximate) orbital solution:

q= 1,3 AU, e= 1, Incl.= 85.5 deg, Peri.= 129.5 deg, Node= 279 deg.

UPDATE (07 April 2009, 14:00 UT)

IAUC Circular 9035 has been released and the new comet is now officially designated C/2009 F6 (YI-SWAN).

According to this IAUC, Dae-am Yi (Yeongwol-kun, Gangwon-do, Korea) has contacted H. Yamaoka, on March 28, informing him about his discovery of a possible comet through a Canon 5D camera + 90-mm telephoto lens. The available astrometry indicate that this is the same object of comet 2009 F6. So, the double denomination.

An Mpec with a preliminary parabolic orbital elements and an ephemeris has been issued too:


UPDATE (07 April 2009, 21:00 UT)

Our image of comet C/2009 F6 (YI-SWAN) rendez-vous with open cluster NGC 7789:


by Ernesto Guido, Giovanni Sostero & Paul Camilleri

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