2010CBET.2117....1K

K. Kinugasa, H. Takahashi, S. Honda, H. Taguchi, and O. Hashimoto, Gunma Astronomical Observatory (GAO), write that a low-resolution spectrum (range 420-800 nm; resolution about 500) of 2010B (cf. CBET 2115), was obtained on Jan. 9.7 UT with the GAO 1.5-m telescope (+ GLOWS). The spectrum shows it to be a type-Ia supernova before maximum light. Adopting the NED recession velocity of 3057 km/s for NGC 5370 (de Vaucouleurs et al. 1991, Third Reference Catalogue of Bright Galaxies, ver. 3.9), the expansion velocity derived from the Si II absorption minimum (rest 635.5 nm) is about 10000 km/s. Comparison with a library of spectra via the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2010B is most similar to SN 2002bo at about four days before maximum.