SN2002cb – discovery

Tom Boles

SN2002cb in MCG +08-24-34, discovered 2002 April 7. IAU Circular 7870 : T. Boles, Coddenham, Suffolk, reports his discovery of an apparent supernova (mag. 17.0) on a 30-s unfiltered CCD image taken on Apr. 7.145 UT (limiting mag. 18.5) with a 0.35-m Schmidt–Cassegrain reflector, in the course of the UK Nova/Supernova Patrol. The new object is confirmed at a similar magnitude in a subsequent image taken by R. Arbour, South Wonston, Hants., on Apr. 7.851 on a 45-s CCD image using a 0.30-m f/6.3 Schmidt–Cassegrain reflector. It is also confirmed by M. Armstrong, Rolvenden, Kent, on Apr. 7.862 (0.35-m Schmidt–Cassegrain + CCD). The object is located at RA 13h 04m 23s.97, Dec +47º 35' 53".2, which is 9".5 east and 6".4 north of MCG +08-24-34. Armstrong gives end figures 23s.92, 53".1. The new object is not present on Palomar Sky Survey images taken on 1991.280 (red limiting mag. 20.5) and 1995.236 (blue limiting mag. 22.0). R. Chornock, W.D. Li and A.V. Filippenko, University of California, Berkeley, report that inspection of CCD spectra (range 330–1000 nm) obtained on Apr. 8 with the Shane 3-m reflector at Lick Observatory reveals that the object is indeed a supernova, of type IIn. The spectrum exhibits weak, narrow emission lines of the hydrogen Balmer series superposed on a smooth, almost featureless blue continuum.