2009CBET.1777....1M

D. Milisavljevic and R. Fesen, Dartmouth College, report that a low-dispersion spectrum (range 420-790 nm) taken of 2009dm (cf. CBET 1773), taken on Apr. 21.2 UT with the 2.4-m Hiltner telescope (+ CCDS) at MDM Observatory, shows it to be a type-II supernova near maximum light. Comparison with a library of supernova spectra using the "Supernova Identification" tool (SNID; Blondin and Tonry 2007, Ap.J., 666, 1024) provides good matches with type-IIP events such as SN 2004et and SN 2005cs within a few days of maximum. A narrow H_alpha emission component corresponds with a SNID calculated redshifted of 0.024. The expansion velocity deduced from the H_alpha absorption is about 9200 km/s.