Volatile Ice Deposits in Lunar Polar Regions and Their Sources

An amalgamation of code adapted from Schorghofer [2014] and Moores [2016] was used to simulate the movement of volatiles on the present-day surface of the Moon. The trapping of volatiles in permanently shadowed regions (PSRs) near the rotational poles was explored using a combination of numerical models of ballistic transport of water vapour. This process included both a validated Monte Carlo model and a full lunar exospheric model, which had not previously been used to explore poleward of 85S or in any part of the northern hemisphere. This work predicts that 5.3% 0.1 of water deposited on the surface of the Moon will be trapped in PSRs. Moreover, the transit times of lunar volatiles to high latitudes and the non-existence of large PSRs in low latitudes create the ideal environment for the largest concentrations of water ice to be found between 83 and 86 latitude, as we see on the lunar surface today. Despite the differences in PSRs available, volatile concentrations follow similar trends in both hemispheres and tend to peak approximately 5 from the poles. These results are produced without the use of the true polar wander theory. In addition to analysing water transport, this work simulates other volatiles observed in the LCROSS impact ejecta plume (H2S, CO2, NH3, CH3OH, C2H4). Analysis of volatile species simulations suggest photodissociation rates dominate trapping efficiency results.