Electronic Telegram No. 2501 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVA 2010ir IN ESO 491-12 J. L. Prieto, Carnegie Observatories, reports that an optical spectrum (range 370-930 nm; resolution 0.7nm) of 2010ir (cf. CBET 2494) was obtained with the APO 3.5-m telescope (+ DIS) on Oct. 14.4 UT. The spectrum shows broad He I and Balmer lines in absorption. After cross-correlation with a library of supernova spectra using SNID (Blondin and Tonry 2007, Ap.J. 666, 1024), 2010ir is found to be most similar to the type-IIb supernova 2000H at 13 days after maximum. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 October 17 (CBET 2501) Daniel W. E. Green