2009CBET.1810....1S

J. M. Silverman, T. N. Steele, B. E. Cobb, and A. V. Filippenko, University of California, Berkeley, report that inspection of CCD spectra (range 350-1000 nm), obtained on May 18 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that 2009eo (CBET 1801) is a type-II supernova. Cross-correlation with a library of supernovae spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2009eo is about one month past maximum and most similar to the normal type-IIn supernova 1998S at 40 days past maximum. After removal of the host-galaxy recession velocity of 13030 km/s, determined from narrow emission lines, the absorption minimum of the H-alpha line (which is much weaker than the emission component) is found to be blueshifted by about 5400 km/s. The emission component of H-alpha has a FWHM of about 6900 km/s. In addition, SN 2009eo exhibits unusually strong He I 587.6-nm emission (though this might be blended with Na I D).