Electronic Telegram No. 1691 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 2009ab IN UGC 2998 A. Harutyunyan, Telescopio Nazionale Galileo (TNG); S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova; and L. Di Fabrizio, TNG, report that a spectrum of 2009ab (cf. CBET 1690), obtained on Feb. 10.83 UT with the 3.5-m TNG (+ DOLORES; range 3500-7800 nm, resolution 1.2 nm), shows it to be that of a type-Ia supernova a few days before maximum light. The best fit to this spectrum found by GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383) is with those of SN 1994D about five days before maximum (Patat et al. 1996, MNRAS 278, 111). Adopting a recession velocity of 3349 km/s (de Vaucouleurs et al. 1991, Third Reference Catalogue of Bright Galaxies, version 3.9; via NED) for the host galaxy, the expansion velocity, deduced from the Si II 635.5-nm absorption minimum, is about 11100 km/s. M. Stritzinger, N. Morrell, and G. Folatelli, on behalf of the Carnegie Supernova Project and the Millennium Center for Supernova Studies, report that they obtained a spectrogram (range 380-940 nm) of 2009ab on Feb. 11.2 UT with the 6.5-m Magellan II (Clay) telecope (+ LDSS3). The spectrum of 2009ab shows it to be a type-Ia supernova at maximum. Adopting a host-galaxy recession velocity of 3349 km/s (de Vaucouleurs et al. 1991, Third Reference Catalogue of Bright Galaxies) for the host galaxy, Si II is measured to be blue-shifted by roughly 11000 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 February 11 (CBET 1691) Daniel W. E. Green