Monday, October 13, 2014

New fragmentation event in C/2011 J2 (LINEAR)

Starting from 2014, Sept 26.9 we are constantly monitoring comet C/2011 J2 (LINEAR) and his fragment B through a 2.0-m f/10.0 Ritchey-Chretien + CCD (La Palma-Liverpool Telescope). The video below shows an animation we made using our recent obs of this comet. Time span is 9 days (from 1 Oct. to 9 Oct). The projected velocity of the fragment is of about 0.3 arcsec/day.

While performing follow-up of component B of comet C/2011 J2 on 2014, Oct 09.9  we detected a possible new diffuse fragment located in the very near proximity of main component A. Nothing was visible on our images taken on Oct. 07.9. Below you can see our Oct. 09.9 image of the new fragment (division by azimutal median filter applied). Click here or on the image below for a bigger version.

We imaged again C/2011 J2 on Oct. 11.9 with the same setup and we confirmed the presence of a new fragment located 1.5" in PA 59 from the main component A. Below you can see our Oct. 11.9 image of the new fragment (stack of 10x20sec raw images, no filters applied). Click here or on the image below for a bigger version. 

While the new fragment is already visible in the raw images, it is even more clearly highlighted by using an appropriate filter. So below you can see the same image as above with a division by azimutal median filter applied. Click here & here or on the images below for a bigger version.

This filter creates an artificial coma, based on the photometry of the original image, and divide the original image itself in order to highlight the internal zones of different brightness that  are very close to the inner core and that would normally be hidden from the diffuse glow of the comet. Precise astrometry/photometry is difficult to obtain due to the extreme proximity and diffuse appearance of new fragment to main component A. New fragment on 2014, Oct 11.9 is definitely brighter than fragment B.

by Ernesto Guido, Nick Howes & Martino Nicolini


Anonymous said...

Do you have new observations of that third fragment ?
J2-B is still here on 29 oct, although decreasing in brightness.

Team said...

Dear Luc, thanks for your message!

A couple of days ago we have received a report from another team (using a "big" telescope) with the confirmation of this third fragment/condensation located nearby the nuclear region of this comet. They sent their report to CBAT and we are waiting for the official circular to be out before publish these new images and info here on the blog. Yes, J2-B too is still there but it is very diffuse and faint by now.