The IAU Circular nr.8979, issued on 2008 Sept. 24, annouces the discovery of a new comet: P/2008 QP20 (LINEAR-HILL). This object has been picked-up in Aries by R. E. Hill through the 0.68-m Schmidt telescope of the Catalina Sky Survey on 2008, Sept.23.3, and afterwards linked by K. Smalley (Minor Planet Center) with an object discovered by the LINEAR sky survey on 2008, Aug. 25.4. Hill's discovery report describe this 18-th comet as having a well condensed coma about 6 to 12 arcsec in diameter, and a narrow tail up to 4' long in PA 250-260 deg.
After its posting on the NEO-CP, several observers confirmed its cometary nature: in general, the comments pointed to a small coma, and a tail pointing toward south-west. We performed some follow-up of this object on Sept. 24.4, remotely from Mayhill (NM), and foud a coma about 10" in diameter and a narrow tail about 30" long in p.a. 233 deg (details on image):
The preliminary orbital elements published on M.P.E.C. 2008-S48 ( http://www.cfa.harvard.edu/mpec/K08/K08S48.html ), points toward a Jupiter-family comet (a~ 3.5 AU, e~ 0.5, i~ 8 deg, P~ 6.5 years); perihelion will be reached at the beginning of November 2008, at about 1.7 AU. The maximum brightness will be reached at the end of next October, at about magnitude 17; it will mostly remain a northern object.
Updated ephemerids are available at the Minor Planet Center:
by Ernesto Guido, Giovanni Sostero and Paul Camilleri