Post eclipse thermal response of Uranian satellites with SINFONI: a status report .

We report on the status of a project to measure eclipse-induced changes in surface temperature on the major Uranian satellites. Such measurements enable a uniquely direct determination of the thermal inertia, a measure of the resistance to changes in surface temperature. Thermal inertia is a very sensitive indicator for the presence or absence of powdered materials and tenuous atmospheres. Two different telescopes and observation techniques are used: The post-eclipse temperature variation of the H_2O-ice component will be determined from analyzing observations of temperature-dependent H_2O absorption features in the near-IR (observations taken in 2007 with SINFONI at VLT). Variations of the disk-integrated thermal emission during and after eclipse events will be observed in the thermal infrared (Q band) using T-ReCS on Gemini South in July 2008.