2010CBET.2328....1C

P. Challis, R. J. Foley, R. Kirshner, E. Berger, A. Soderberg and G. H. Marion, Harvard-Smithsonian Center for Astrophysics, report that CCD spectra (range 345-865 nm), obtained on June 17 UT with the 6.5-m MMT (+ Blue Channel spectrograph) at Mount Hopkins, show that 2010dq (cf. CBET 2303) is type-Ia supernova. SN 2010dq shows the prominent Ti II feature associated with low-luminosity supernovae like SN 1991bg near maximum light (e.g., Filippenko et al. 1992, A.J. 104, 1543; Leibundgut et al. 1993 A.J. 105, 301). The Si II absorption is blueshifted by 11350 km/s. Cross-correlation with a library of supernova spectra, using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024), indicates that 2010dq is most similar to SN 1991bg at three days after maximum brightness. Observations with the same equipment show that 2010dr (cf. CBET 2304) is a type-II supernova. The H-alpha and H-beta lines of 2010dr have only broad triangular emission components. H-alpha has a FWHM of 7500 km/s. The spectrum is similar to those of SN 1979C (e.g., Panagia et al. 1980, MNRAS 192, 861) and SN 1998S (e.g., Leonard et al. 2000, Ap.J. 536, 239) a few months past maximum brightness; no narrow component is detected, suggesting that SN 2010dr is likely of type IIL.