Friday, July 1, 2011

Unusual asteroid 2011 MM4

M.P.E.C. 2011-N02, issued on 2011, July 01, announces the discovery of a intriguing new object (discovery magnitude 21.1) by the Pan-STARRS survey with their PS1 1.8-m Ritchey-Chretien + CCD, on images obtained on 2011, June 24.4. This new object has been designated 2011 MM4.

We performed some follow-up measurements of 2011 MM4 while it was still listed in the NEOCP with the 2.0-m Haleakala-Faulkes Telescope North on June 30.4 and July 01.4, 2011.

Stacking of twenty-one R-filtered exposures, plus seven V-filtered exposures, 60-sec each, obtained remotely, from the Haleakala-Faulkes Telescope North on 2011, July 1.4, through a 2.0-m f/10.0 Ritchey-Chretien + CCD under good seeing conditions, shows that this object has the same FWHM (1.3 arcsec) of the nearby field stars having similar brightness.

Even if this object has no signs of any obvious coma in our images, it is very interesting due to his peculiar comet-like retrograde orbit. According to the very preliminar orbit published on discovery MPEC, 2011 MM4 is actually ~13.5 AU (with aphelion around 25 AU) from the sun, eccentricity =0.43, P=64.3 years, H=9.4 and it has an inclination of 99 degree.

Our confirmation image (click on the image to see a bigger version)

by Nick Howes, Giovanni Sostero and Ernesto Guido

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