DUST TO DUST: THREE YEARS IN THE EVOLUTION OF THE UNUSUAL SN 2008S

We obtained late-time optical and near-IR imaging of SN 2008S with the Large Binocular Telescope, near-IR data with the Hubble Space Telescope, and mid-IR data with the Spitzer Space Telescope. We find that (1) it is again invisible at optical (UBVR) wavelengths to magnitude limits of approximately 25 mag, (2) while detected in the near-IR (H) at approximately 24.8 mag, it is fading rapidly, and (3) it is still brighter than the progenitor at 3.6 and 4.5 μm in the mid-IR with a slow, steady decline. The IR detections in 2010 December are consistent with dust emission at a blackbody temperature of T ≅ 640 K and a total luminosity of L ≅ 200,000 L☉, much higher than the L ≅ 40,000 L☉ luminosity of the obscured progenitor star. The local environment also shows no evidence for stars significantly more massive than 10 M☉, consistent with the progenitor being an 8-10 M☉ super asymptotic giant branch star.