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.
M.P.E.C. 2011-S28 assignes the following preliminary orbital elements to comet C/2011 S1 (GIBBS): 2013 Jan. 16.54; e= 1.0; Peri. =174.65; q = 4.99 AU; Incl.= 2.23
by Giovanni Sostero, Nick Howes and Ernesto Guido