CBET circular No. 2249, issued on 2010, April 17, announces the discovery by J. Vales of an unusually bright (magnitude 12.6) asteroidal object on Apr. 16, 2010, observing with the 0.60-m f/3.3 Deltagraph at Crni Vrh (mpc code 106), Slovenia. R. A. Kowalski of Catalina Sky Survey (CSS), reports that the object is not visible in images down to magnitude V=20 obtained by the CSS Survey as recently as April 15.4 UT.
After posting on the Minor Planet Center's NEOCP webpage, W. Ryan (H01) and E. Guido & G. Sostero (H06) have commented that the new object has an FWHM consistently wider (about 10%) than nearby field stars of similar brightness, confirming the cometary nature of this object designated P/2010 H2.
We have been able to confirm this object remotely, through the GRAS network, using a scope located in Mayhill (NM): Analysis of the stacking of 6 ulfiltered exposures, 120-seconds each,obtained remotely on 2010 Apr. 16.42 show that this object has an FWHM consistently wider than the nearby field stars of similar brightness. An additional stacking,of 6 unfiltered exposures, 30-sec each, obtained through the same instrumentation on 2010 Apr. 16.43, confirm this evidence. In our opinion, its appearance strictly resembles that of comet 17P/Holmes in the early phases of its October 2007 outburst phase.
Our confirming image:
The still-very-preliminary elliptical orbit shows perihelion on May 21, 2010, at about 3.07 AU.
Follow-up observations are strongly encouraged. It is expected that an expanding coma will develop over the next days and weeks.
by Ernesto Guido & Giovanni Sostero