PYTS 395B Detecting Ice on the Moon 1 Mercury and the Moon possesses a tenuous atmosphere Calcium now also seen at Mercury Sodium emission at the Moon and Mercury shows temporal changes Stirring of regolith by small impacts PYTS 395B Detecting Ice on the Moon Evidence for ice in polar craters of Mercury Evidence for ice at lunar poles Clementine bi static radar Lunar prospector neutron Evidence for ice at poles of Mercury VLA radar returns Sungrazing comets Kreutz group Source of water 2 PYTS 395B Detecting Ice on the Moon 3 PYTS 395B Detecting Ice on the Moon Feldman et al 1998 4 PYTS 395B Detecting Ice on the Moon Bussey et al 1999 5 PYTS 395B Detecting Ice on the Moon 6 Margot et al 1999 PYTS 395B Detecting Ice on the Moon Modeling Vasavada et al 1999 shows temperatures in permanently shadowed craters are very low These cold traps are favored condensation sites Vasavada et al 1999 7 PYTS 395B Detecting Ice on the Moon Water leaves cold traps by sublimation 5 15 returns on Mercury 20 50 returns on the Moon The rest is lost Water can be delivered by meteors and comets For Mercury these rates have been estimated Balance exists if Tice is 113K Killen et al 1997 8 PYTS 395B Detecting Ice on the Moon Lunar cold traps dry compared to Mercury Recent comet impact Polar inconsistency More H in lunar north pole More permanent shadows in lunar south pole Burial depth differences Dispersed grains 9
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