Update about comet 19P/Borrelly

Further follow up performed by the undersigneds with the same instrumental set-up of our previous report (but with 600-sec total integration time) on 2009, May 17.21, shows that the secondary condensation (or knot) that has been reported on comet 19P/Borrelly (see our previous post) has significantly weakened, with an aspect extremely diffuse and elongated compared to our previous observation of May 15.21.

On May 17.21 the optocenter (difficult determination) of this feature had a displacement of about 4 arcsec in PA 301 with respect to the central condensation of 19P/Borrelly.

Our image is available here:

http://tinyurl.com/qnvpvw


Giovanni Sostero, Paul Camilleri, Enrico Prosperi & Ernesto Guido

Secondary condensation on 19P/Borrelly

Prompted by an alert note of Bernhard Haeusler, posted in the newsgroup [Comets-ml] on May 11, 2009 about a possible secondary "condensation" in 19P/Borrelly, we performed some follow-up about this comet.

Images obtained by the undersigneds on 2009, May 15.21 with the 0-61-m Cassegrain + CCD of the Sierra Stars Observatory (Maarkleville, CA) confirms the presence of a tailward, diffuse, secondary condensation or "knot", placed about 4.7 arcsec in PA 301 from the primary central condensation. This feature is nearly 1.5 magnitude fainter compared to the central condensation itself. Image processing techniques (azimuthal median subtraction of the inner coma) enhances the visibility of this detail.

Our image is available here:

http://tinyurl.com/qendnd

Comparing the offset data posted in the same blogspot by B. Hausler (May 7: 13 arcsec in PA 310) and F. Kugel (May 10: 8 arcsec PA 305), this feature apparently approaches the central condensation; however some foreshortening effect might be under course, also considering the fact that, on about 2009 June 5th, Earth will cross the orbital plane of this comet.

Paul Camilleri, Enrico Prosperi, Giovanni Sostero & Ernesto Guido