[IAUC] CBET 1198: 20080106 : SUPERNOVA 2008A IN NGC 634

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                                                  Electronic Telegram No. 1198
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 2008A IN NGC 634
     S. Blondin, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf
of the CfA Supernova Group, reports that a spectrogram (range 350-740 nm) of
2008A (cf. CBET 1193), obtained by P. Berlind on Jan. 5.08 UT with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a peculiar
type-Ia supernova around one week before maximum light.  Cross-correlation
with a library of supernova spectra using the "Supernova Identification" code
(SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2008A is most
similar to the peculiar 2002cx-like type-Ia supernova 2005hk (Phillips et
al. 2005, PASP 119, 360) at one week before maximum.  The spectrum of 2008A
consists of a blue continuum with P-Cyg profiles of high-ionization lines
characteristic of the overluminous type-Ia supernova 1991T; yet the discovery
magnitude of 17.6 corresponds to an absolute magnitude of -16.6 (assuming the
galaxy is in the Hubble flow and the supernova suffers negligible extinction),
similar to underluminous, 1991bg-like supernovae at a similar age.  This was
also the case for the peculiar supernova 2005hk, which confirms the
resemblance between 2008A and 2005hk.  Adopting a recession velocity of 4867
km/s for the host galaxy (from The Updated Zwicky Catalog, available at URL
http://tdc-www.harvard.edu/uzc/), the maximum absorption in the weak Si II
line (rest 635.5 nm) is blueshifted by roughly 7000 km/s, while the maximum
absorptions in the Fe III lines (rest 440.4 nm and 512.9 nm) are blueshifted
by roughly 8500 km/s.  These relatively small blueshifts are characteristic
of supernova-2002cx-like events.


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                         (C) Copyright 2008 CBAT
2008 January 6                   (CBET 1198)              Daniel W. E. Green