[IAUC] CBET 1222: 20080124 : SUPERNOVA 2008D IN NGC 2770

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                                                  Electronic Telegram No. 1222
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2008D IN NGC 2770
     NOTE:  this replaces the text on CBET 1221:

     M. Modjaz, R. Chornock, R. J. Foley, A. V. Filippenko, and W. Li,
University of California at Berkeley; and G. Stringfellow, University of
Colorado, report that a spectrum (range 350-970 nm) taken of SN 2008D (cf.
CBETs 1202, 1205), obtained by Stringfellow on Jan. 21.22 UT with the
Astrophysical Research Consortium 3.5-m telescope (+ DIS) at Apache Point
Observatory, shows it to be a type-Ib supernova.  The fully reduced
spectrum shows the development of conspicuous lines of He I (rest 447.1,
587.6, 667.8, and 706.5 nm), with the maximum absorptions blueshifted by
roughly 10000-11000 km/s (assuming a recession velocity for the host galaxy
of 1947 km/s).  This spectrum, when de-reddened by an A_V value of about 2
mag, is very similar to spectra of the type-Ib supernova 2005hg (cf. CBET
271; Modjaz et al., in preparation), about 1 week before maximum.  Cross-
correlation with a library of supernova spectra using the "Supernova
Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024)
indicates that the spectrum of SN 2008D is also similar to that of the
type-Ib supernova 1998dt (IAUCs 7006, 7011) at maximum light (Matheson et
al. 2001, A.J. 121, 1648).  Modjaz et al. furthermore detect strong absorption
at 615 nm that could be due to Si II (rest 635.5 nm) at 10000 km/s or,
alternatively, very-high-velocity H-alpha at 19000 km/s.  SN 2008D was
previously classified as a type-Ib/c supernova (GCN 7169), a peculiar type-Ic
supernova (CBET 1205), and a normal type-Ic supernova (GCN 7184) with possibly
some He as seen in near-infrared spectra (GCN 7188).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2008 CBAT
2008 January 24                  (CBET 1222)              Daniel W. E. Green