[IAUC] CBET 1381: 20080520 : SUPERNOVA 2008S IN NGC 6946

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                                                  Electronic Telegram No. 1381
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 2008S IN NGC 6946
     R. Wesson, J. Fabbri, and M. Barlow, University College, London; and M.
Meixner, Space Telescope Science Institute, on behalf of the 'Survey for
Evolution of Emission from Dust in Supernovae' (SEEDS) collaboration, report
the detection of the type-IIn supernova 2008S in Spitzer Space Telescope IRAC
and MIPS images that were obtained serendipitously on 2008 Feb. 7 UT, five
days after the supernova outburst, during scheduled observations of the nearby
supernova 2002hh (cf. IAUC 8005).  SN 2008S is detected at R.A = 20h34m45s.34,
Decl. = +60o05'58".0 (equinox 2000.0; +/- 0".4 in each coordinate), in close
agreement with the optical position (CBET 1234).  The measured flux densities
in mJy at 3.6, 4.5, 5.8, 8.0, and 24 microns are 1.7 +/- 0.3, 2.0 +/- 0.3, 2.7
+/- 0.4, 4.0 +/- 0.4, and 0.4 +/- 0.3, respectively.  This spectral-energy
distribution (SED) can be fitted by a 500-K black body modified by a dust
emissivity that is inversely proportional to wavelength, giving a luminosity
of 2.1 x 10^6 solar luminosities for a distance of 5.6 Mpc to the host galaxy
NGC 6946.  The progenitor of SN 2008S was detected in archival Spitzer images
by Prieto et al. (2008, http://arxiv.org/abs/0803.0324v3), who found that a
440-K blackbody with a luminosity of 3 x 10^4 solar luminosities could fit
the progenitor's infrared SED.


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                         (C) Copyright 2008 CBAT
2008 May 20                      (CBET 1381)              Daniel W. E. Green