Program: GN-2008B-Q-44

The face-on spiral galaxy NGC 6946 has produced nine SNe since 1917, with SN2008S, of Type IIn, discovered on 1/2/08. A dust-emitting, optically self-obscured progenitor, with L=3.5e4 Lsun, has been identified on archival Spitzer images of the galaxy. A bright source coincident with SN 2008S was serendipitously detected by us with Spitzer in the field of SN 2002hh, at day 5/6 after outburst, with an IR colour temperature of 600-700K and a luminosity of ~2.2e6 Lsun. We propose to obtain Michelle mid-IR photometry and GMOS optical photometry and spectroscopy of SN 2008S at the start of 08B, about 6 months after outburst, in order to characterise its optical and IR light-curve and SED and to begin a search for the optical spectroscopic signatures of dust formation within its ejecta. SN 2004et in NGC 6946 has also been monitored by us with Spitzer and Gemini. Between days 1050 and 1191 its mid-IR flux tripled, indicating a very late dust emission event. We propose to obtain MIchelle 11.2um and GMOS optical photometry for SN 2004et in 08B, in order to study and quantify the dust evolution around this SN.