2012CBET.3226....2D

M. Dennefeld, Institute d'Astrophysique de Paris and Paris6 University; A. Pizzella, Padova University; M. Valentini, Liege University; L. Tomasella and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova; and the NEON school (cf. IAUC 7664) students M. Cortes (Spain), N. Ozel (Belgium), and A. Rajpurohit (France), report that a spectrogram of PSN J23423882+2705315 = SN 2012et, obtained on Sept. 13.80 UT with the 1.82-m Copernico telescope (+ Afosc spectrograph; range 350-820 nm, resolution 1.3 nm), suggests that this is a type-Ia supernova. Adopting for the host galaxy (MCG +04-55-47) a redshift z = 0.024961 (Saintonge et al. 2008, A.J. 135, 588; via NED), a comparison with a library of supernova spectra via GELATO (Harutyuyan et al. 2008, A.Ap. 488, 383) shows that 2012et is a type-Ia event similar to several type-Ia supernovae few days before maximum light. The expansion velocity measured from the Si II 635.5-nm minimum is about 15000 km/s, which places it among the high-velocity-gradient type-Ia supernovae (Benetti et al. 2005, Ap.J. 623, 1011).