2008CBET.1381....1W

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.