Planetary Science Seminar spring-2017

The small obliquity of Mercury causes topographic depressions located near its poles to cast persistent shadows that can trap water ice for geologic time periods. Recently, direct evidence for the presence of water ice deposits inside these cold-traps was remotely sensed in RADAR and visible imagery. Albedo measurements obtained by the MESSENGER Laser Altimeter (MLA) found unusually dark deposits next to Mercury’s north pole, indicative of ice buried under a sublimation lag. We use a 3D thermal illumination model to find a large fraction of the polar ice on Mercury resides inside cold-traps of scales 10-100 m (below the instrument resolution). We derive the thickness of ice inside these cold-traps, and use it to estimate the rate at which volatiles are accumulated on Mercury.