[IAUC] CBET 1300: 20080312 : SUPERNOVAE 2008U AND 2008X

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                                                  Electronic Telegram No. 1300
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVAE 2008U AND 2008X
     Editor's note:  the text below was sent as a replacement to the text
on CBET 1242.
      S. Blondin, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf
of the CfA Supernova Group; R. Barbon, Osservatorio Astrofisico di Asiago,
Universita' di Padova; and A. Pastorello, Queen's University, Belfast, report
that a spectrum (range 350-740 nm) of 2008U (cf. CBET 1238), obtained on Feb.
8.46 UT by M. Calkins with the F. L. Whipple Observatory 1.5-m telescope (+
FAST), shows it to be a type-II supernova several weeks past explosion.  The
spectrum consists of a red continuum and P-Cygni profiles of the Balmer
series, Na I D and Fe II.  H_alpha displays a broad (FWHM approximately 3000
km/s) emission component not present in the other Balmer lines.  These
spectral characteristics are typical of type-II supernovae during the hydrogen
recombination phase.  Adopting a recession velocity of 3730 km/s for the host
galaxy of 2008U (from The Updated Zwicky Catalog), the maximum absorption in
the H_alpha line (rest 656.3 nm) is blueshifted by roughly 5000 km/s.
     Blondin et al. add that a spectrum (range 350-740 nm) of 2008X (cf. CBET
1239), obtained as above on Feb. 8.43 UT by Calkins, shows it to be a type-II-
plateau supernova 3-4 weeks past explosion.  Cross-correlation with a library
of supernova spectra using the "Supernova Identification" code (SNID; Blondin
and Tonry 2007, Ap.J. 666, 1024) indicates that 2008X is most similar to the
type-II-plateau supernova 2005cs at 3 weeks past explosion.  Adopting a
recession velocity of 1948 km/s for the host galaxy of 2008X (from The Updated
Zwicky Catalog, http://tdc-www.harvard.edu/uzc/), the maximum absorption in
the H_alpha line (rest 656.3 nm) is blueshifted by roughly 4000 km/s.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2008 CBAT
2008 March 12                    (CBET 1300)              Daniel W. E. Green