Electronic Telegram No. 2311
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
 Sciences; Harvard University; 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbat@iau.org; cbatiau@eps.harvard.edu
URL http://www.cfa.harvard.edu/iau/cbat.html


SUPERNOVAE 2010do, 2010dw, 2010dt
     P. Challis, R. Foley, G. H. Marion, and R. Kirshner, Harvard-Smithsonian
Center for Astrophysics (CfA); and J. Ruel, Physics Department, Harvard
University, on behalf of the CfA Supernova Group, report on spectroscopic
observations that were obtained of 2010do, 2010dt, and 2010dw by P. Berlind
on June 7 UT with the F. L. Whipple Observatory 1.5-m telescope (+ FAST;
range 360-760 nm) and of 2010do by R. J. Foley and J. Ruel on June 8 with the
Magellan telescope (+ IMACS; range 630-950 nm).
     SN 2010do (cf. CBET 2301) is a type-Ic supernova near maximum light.
Cross-correlation with a library of supernova spectra using the "Supernova
Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) finds
that the spectrum of 2010do is similar to that of SN 1994I at maximum light.
However, the presence of weak He I features cannot be ruled out.  Using
4382 km/s as the heliocentric velocity for the host galaxy (Paturel et al.
2003, A.Ap. 412, 57), the velocity for Ca II is about 14000 km/s, measured
at the absorption minima of features from the H and K lines and the
infrared triplet.  C II lines at 658.0 and 723.5 nm are measured at about
6000 km/s.
     SNID indicates that 2010dw (cf. CBET 2310) is a normal type-Ia
supernova a few days before maximum light, and 2010dt (cf. CBET 2307) is a
normal type-Ia supernova near maximum light.

     I. K. W. Kleiser, S. B. Cenko, J. M. Silverman, and A. V. Filippenko,
University of California, Berkeley, report that inspection of a CCD spectrum
(range 340-980 nm), obtained on June 8 UT with the 3-m Shane reflector (+
Kast) at Lick Observatory, shows that SN 2010do is a normal type-Ic supernova.
Cross-correlation with a library of supernova spectra using the SNID code of
Blondin and Tonry (2007, Ap.J. 666, 1024) indicates that 2010do is about two
days after maximum light.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 June 9                      (CBET 2311)              Daniel W. E. Green