New Constraints on Lunar Heat Flow Rates from LRO Diviner Lunar Radiometer Experiment Polar Observations
Introduction: The heat flow rate from the lunar interior is a fundamental property of the moon that is related to its composition, interior structure and history. Lunar heat flow rates have been measured at the Apollo 15 and 17 landing sites [1] but it is likely that the measured values of 21 mWm and 14 mWm respectively may not be representative of the moon as a whole due to the presence of enhanced radiogenic elements at these landing sites [2,3] The Diviner Lunar Radiometer Experiment on the Lunar Reconnaissance Orbiter [4] has acquired an extensive set of thermal emission from the lunar surface at infrared wavelengths, including the first radiometric measurements of surface temperatures at the lunar poles [5] Due to its low obliquity and rough topography, the moon has permanently shadowed cryogenic regions at high latitudes that never receive direct sunlight. The temperatures of the coldest of these regions can be used to place upper limits on the heat flow rate from the lunar interior because if other heat sources are neglected, then surface thermal emission is balanced by heat flow from warmer lunar interior [6]