Electronic Telegram No. 2138 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2010N Further to CBET 2131, A. J. Drake, S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology; J. Prieto, Carnegie Observatories; M. Catelan, Pontificia Universidad Catolica de Chile; E. C. Beshore and S. M. Larson, Lunar and Planetary Laboratory, University of Arizona; and E. Christensen, Gemini Observatory, report the CRTS discovery of an apparent supernova in unfiltered Catalina Sky Survey (CSS) images: SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010N Jan. 12.50 13 09 05.24 +17 04 22.3 16.7 -- Nothing was visible at this position on a CSS image from 2009 July 30.15 (limiting mag 18.5). I. K. W. Kleiser, J. M. Silverman, S. B. Cenko, and A. V. Filippenko, University of California, Berkeley, report that inspection of CCD spectra (range 350-1020 nm), obtained on Jan. 16 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that 2010N is a type-Ia supernova that SNID (Blondin and Tonry 2007, Ap.J. 666, 1024) indicates is about 2 to 3 weeks past maximum. From narrow emission features, it is found that the recession velocity of 2010N's host galaxy is about 6400 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 January 22 (CBET 2138) Daniel W. E. Green