2008CBET.1204....1B

S. Blondin, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group; T. Matheson, National Optical Astronomy Observatory; and M. Modjaz, University of California at Berkeley, report that a spectrum (range 320-840 nm) of 2008D (cf. CBET 1202), obtained on Jan. 11.41 UT by P. Berlind with the MMT 6.5-m telescope (+ Blue Channel spectrograph), shows it most likely to be a peculiar type-Ic supernova in its early phases. The spectrum consists of a relatively blue continuum, with P-Cyg profiles (FWHM of approximately 10000 km/s) that are characteristic of a supernova spectrum blueward of 550 nm, and an extremely broad emission feature peaking at approximately 630 nm that is similar to the [O I] doublet (rest 630.0, 636.4 nm) seen in the spectra of broad-line type-Ic supernovae around maximum light. More specifically, the double- absorption feature centered on 420 nm resembles that seen in the earliest spectrum of the normal type-Ic supernova 1990aa (cf. IAUC 5087, 5111; Matheson et al. 2001, A.J. 121, 1648), while the broad feature centered on 630 nm resembles the [O I] bump seen in spectra of the broad-line type-Ic supernova 1998bw (associated with GRB 980425; cf. IAUC 6895, 6901; Patat et al. 2001, Ap.J. 555, 900) around maximum light (roughly three weeks after the gamma-ray-burst detection).