Further fragmentation events in 213P/Van Ness

Stacking of 9 R-filtered exposures, 120-sec each, obtained remotely, from the Siding Spring-Faulkes Telescope South on 2011, September 20.6, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, shows that fragment b of comet 213P is still visible, albeit very faint and diffuse (m2 about 21.5, coma diameter about 5-arcsec). Fragment b was located about 5.7 arcmin in PA 240 respect the main nuclear condensation of 213P/Van Ness.

During the same observing session, we noticed also the presence of a new fragment, not visible on our past images obtained with the same set-up (the last of which dates back 2011, Sep. 2.5): this additional fragment (that we called below "part-y") appears slightly brighter and compact than 0213Pb itself (m1 about 21.0, coma diameter about 4-arcsec elongated toward the southwest). "part-y" was located about 4.5 arcmin in PA 239 respect the main nuclear condensations of 213P/Van Ness.

Our image of Sept. 20.6 about these fragments is available here:

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

We obtained additional follow-up through the same instrumentation on 2011, Sep. 21.6, confirming the existence of both fragments b and "part-y". Further inspection of our images, exclude the presence of other fragments brighter than magnitude R about 22, up to 12-arcmin tailward of 213P.

UPDATE - SEPTEMBER 23, 2011

Stacking of 11 R-filtered exposures, 120-sec each, obtained remotely, from the Siding Spring-Faulkes Telescope South on 2011, September 23.6, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, shows that fragment b of comet 213P/Van Ness is now extremely weak and diffused (uncondensed coma about 7-arcsec in diameter) that hampers any astrometric measurement about it (however this might be a temporary disappearance, as sometimes happens with these small cometary fragments in rapid evolution).

On today's images we found again the fragment we reported first on 2011, Sep. 20.58846 (at that time we called it "part-y").

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

by Giovanni Sostero, Ernesto Guido & Nick Howes

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

Update about 213P/Van Ness fragmentation

On August 9, 2011 we have obtained follow-up images of comet 213P/Van Ness + fragment.

For more information about this event see our previous post:
http://remanzacco.blogspot.com/2011/08/fragmentation-event-in-213pvan-ness.html

Stacking of ten exposures, 60-sec each, obtained remotely from the Haleakala-Faulkes Telescope North on 2011, Aug. 9.6, through a 2.0-m f/10.0 Ritchey-Chretien + CCD + Bessel-R filter, under good seeing conditions, shows some evolution of the fragment "b" of comet 213P.

The brightness of its central condensations appears to be dropped by about half a magnitude, compared to our previous observing session on 2011, Aug. 5.6. The central condensation itself appears now elongated, extending nearly 3" in PA 235. The tail of this fragment has been measured to be nearly 16" in PA 233.

Our image (click for a bigger version):

by N. Howes, H. Blyth, G. Sostero, E. Guido

Fragmentation event in 213P/Van Ness

Today, during our observing session with Faulkes Telescope North we observed a fragmentation event in comet 213P/Van Ness.

Stacking of five exposures, 120-sec each, obtained remotely from the Haleakala-Faulkes Telescope North on 2011, Aug. 5.5, through a 2.0-m f/10.0 Ritchey-Chretien + CCD + Bessel-R filter, under good seeing conditions, shows the presence of a secondary fragment embedded in the tail of comet 213P/Van Ness. This object, we named "parte-b", was placed about 5.3 arcmin in PA 239, with respect to the central condensation of the comet. It shows a tiny coma nearly 5-arcsec in diameter, with a tail of at least 22-arcsec in PA 235. Its m1 is R about 20, while its central condensation has R about 21.

A confirmatory observing session with the same set-up, has been obtained on 2011, Aug. 5.6: stacking of six exposures, 120-sec each shows again the fragment in the expected position, moving with the same proper motion of the comet.

Below you can see our total stacked image of comet 213P/Van Ness and its fragment (click on the image for a bigger version):



Comet 213P shows also an obvious anti-tail, or dust-trail, at least 6-arcmin long in PA 58. Below our rendition of this feature, obtained during the same observing session (click on the image for a bigger version):

by G. Sostero, H. Blyth, N. Howes and E. Guido