2010CBET.2333....1S

J. M. Silverman, C. V. Griffith, M. T. Kandrashoff, and A. V. Filippenko, University of California, Berkeley, report that inspection of a low-signal-to- noise-ratio CCD spectrum (range 340-1000 nm), obtained on June 18 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that 2010ee (CBET 2326) is a type-II supernova; H-alpha has a well-developed P-Cyg profile. After removal of the host-galaxy recession velocity of 8500 km/s, determined from narrow emission features, the absorption minimum of the H-alpha line is found to be blueshifted by about 5500 km/s.

SN 2010ei (CBET 2329) is a type-II supernova, probably of subtype IIb, 1-2 weeks after the explosion. After removal of the host-galaxy recession velocity of 5600 km/s, determined from narrow emission features, the absorption minimum of the H-alpha line is found to be blueshifted by about 16300 km/s. However, this may be a slight overestimate if H-alpha has some residual blending with Si II 635.5 nm, which was seen at a similar velocity in the type-IIb supernova 2003bg at one week past explosion (Hamuy et al. 2009, Ap.J. 703, 1612).

SN 2010ek (CBET 2329) is a type-IIb supernova a few days before maximum brightness. Cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2010ek is 4 days before maximum. After removal of the host-galaxy recession velocity of 9400 km/s, determined from narrow emission features, the absorption minimum of the H-alpha line is found to be blueshifted by about 11500 km/s.