Electronic Telegram No. 1992
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html


SUPERNOVAE 2009ju, 2009jx, AND 2009ka
     P. Challis, Harvard-Smithsonian Center for Astrophysics (CfA), on
behalf of the CfA Supernova Group, reports that a spectrum (range 330-850
nm) of 2009ka (cf. CBET 1985), obtained on Oct. 21 UT by S. Tang with the
F. L. Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a
type-IIb supernova.  Cross-correlation with a library of supernova spectra
using the "Supernova Identification" code (SNID; Blondin and Tonry 2007,
Ap.J. 666, 1024) indicates that 2009ka best matches type-IIb supernovae.
     J. Brimacombe, Cairns, Australia, reports that SN 2009ka appears to be
brighening; a stack of eight 300-s luminance-filtered images (limiting
magnitude 19.5) taken using a 0.4-m reflector on Oct. 22.45 UT revealed
magnitude 16.9.  A follow-up stack of ten 600-s luminance-filtered images
(limiting magnitude 21.0) taken remotely with a 0.5-m reflector in New
Mexico on Oct. 23.2 revealed 2009ka at magnitude 17.0.  The images have been
posted at website URL http://www.flickr.com/photos/43846774@N02.
     J. M. Silverman and A. V. Filippenko, University of California, Berkeley;
and R. J. Foley, Harvard-Smithsonian Center for Astrophysics, report that
inspection of CCD spectra (range 340-1010 nm), obtained on Oct. 22 UT with the
Keck I 10-m telescope (+ LRIS), shows that 2009ju (CBET 1974) is a type-II
supernova; the H-alpha emission component greatly dominates over the
absorption.  SN 2009jx (CBET 1979) is also a type-II supernova, shortly after
explosion; the spectrum is quite blue and nearly featureless, showing only
very weak Balmer lines.  A spectrum of 2009ka shows it to be a type-II
supernova, probably of type IIb (although the He I lines are not yet obvious);
cross-correlation with a library of supernova spectra using the "SuperNova
IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates
that it is most like the type-IIb supernova 1993J about four days before
maximum light.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2009 CBAT
2009 October 23                  (CBET 1992)              Daniel W. E. Green