Update about 213P-B fragment

MPECs 2011-P25, 2011-P37 and CBET 2798 detailed the discovery and follow-up about a secondary nuclear condensation (component B) of comet 213P/VAN NESS. Recently we performed some additional follow-up on it, in order to check its evolution.

Stacking of eight exposures, 60-sec each, obtained remotely from the Haleakala-Faulkes Telescope North on 2011, Aug. 25.5, through a 2.0-m f/10.0 Ritchey-Chretien + CCD + Bessel-R filter under good seeing conditions, shows that fragment "b" of comet 213P/Van Ness is still present, however now it is very weak (R magnitude about 21) and diffused (coma diameter about 4-arcsec); this hampers any accurate astrometric measurement. 

Astrometry:
0213P      b KC2011 08 25.50468 23 07 14.86 +04 07 51.8          21.1 R      F65
0213P      b KC2011 08 25.50797 23 07 14.68 +04 07 51.8          21.2 R      F65
0213P      b KC2011 08 25.51061 23 07 14.56 +04 07 52.2          21.4 R      F65

You can see the image below (click on it for a bigger version)

Stacking of six exposures, 120-sec each, obtained remotely with the same instrumentation on 2011, Sep. 2.5, confirms the previous observations, and indicates another decline in its brightness and degree of condensation. The coma has been measured to be nearly 5-arcsec in diameter.  

Astrometry:
0213Pb        C2011 09 02.50427 23 00 49.98 +04 24 17.8          21.3 N      F65
0213Pb        C2011 09 02.50625 23 00 49.91 +04 24 18.1          21.5 N      F65
0213Pb        C2011 09 02.50826 23 00 49.85 +04 24 19.0          21.3 N      F65

You can see the image below (click on it for a bigger version)

Click on the thumbnail below to see a short animation showing the fragment motion:

by Giovanni Sostero, Nick Howes and Ernesto Guido