2012CBET.3035....2J

S. W. Jha, C. McCully, and B. Patel, Rutgers University, report that a spectrum (range 460-980 nm) of SN 2012an = PSN J17241023+5900069, taken on Feb. 26.7 UT with the Keck II 10-m telescope (+ DEIMOS), shows it to be a type-IIb supernova, likely one to two weeks after explosion. The spectrum shows strong P-Cyg profiles of H-alpha and He I 587.6-, 667.8-, and 706.5-nm. Adopting a recession velocity for NGC 6373 of 3320 km/s (Falco et al. 1999, PASP 111, 438) yields an expansion velocity of 12900 km/s (from the H-alpha minimum) or 9000 km/s (from the minima of the He I features). Cross- correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) yields a good match to the type-IIb supernova 1997dd, though with an uncertain age.