Electronic Telegram No. 2177 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbat@cfa.harvard.edu; dwe_green@eps.harvard.edu URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2010ad IN UGC 10143 Further to CBET 2169, J. Rex, S. B. Cenko, W. Li, and A. V. Filippenko, University of California, report the LOSS discovery of an apparent supernova on unfiltered KAIT images: SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010ad Feb. 18.57 16 02 13.56 +15 56 18.8 16.0 5".2 E, 3".8 N Nothing is visible at this position on a KAIT image from 2009 Sept. 9.15 UT. J. M. Silverman, M. T. Kandrashoff, and A. V. Filippenko, University of California, Berkeley, report that inspection of a low-signal-to-noise- ratio CCD spectrum (range 360-990 nm), obtained on Feb. 19 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that 2010ad is a supernova, probably of type II. Cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code of Blondin and Tonry (2007, Ap.J. 666, 1024) indicates that 2010ad is most similar to the spectrum of the type-IIb supernova 1993J about a week past maximum brightness. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 February 19 (CBET 2177) Daniel W. E. Green