P43F-06
Hydrogen Bearing Material in the Lunar Exosphere
Thursday, 17 December 2015: 14:55
2007 (Moscone West)
Dana Hurley1, Mehdi Benna2, Anthony Colaprete3, Kurt D Retherford4, Jason Campbell Cook5, Richard C Elphic3, William M Farrell6, Rosemary M Killen2, Menelaos Sarantos7 and LRO LAMP Science Team and LADEE Science Team, (1)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, (2)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (3)NASA Ames Research Center, Moffett Field, CA, United States, (4)Southwest Research Institute, San Antonio, TX, United States, (5)Southwest Research Institute Boulder, Boulder, CO, United States, (6)NASA Goddard SFC, Greenbelt, MD, United States, (7)Goddard Earth Sciences and Technology Center, Greenbelt, MD, United States
Abstract:
We report on observations of water and its daughters in the lunar exosphere. Data from LADEE NMS, LADEE UVS, and LRO LAMP indicating the presence of H, H2, OH, and H2O are presented in terms of their relationship to external drivers. These observations point to the roles of solar wind and micrometeoroids in the source and release of hydrogen-bearing atoms and molecules in the exosphere. In particular, the implantation of H via solar wind is found to be the largest contributor to H2 in the moon’s exosphere. However, the spatial distribution is more consistent with a release mechanism centered on the morning hemisphere. Thus the data are consistent with H2 created through a 2-step process involving the implantation of solar wind and subsequent release by micrometeoroids. This accounts for >12% of the solar wind H budget, leaving < 50% of the solar wind proton budget unobserved. LADEE data are consistent with water mainly being released by micrometeoroids. We present an overall picture of the present-day water cycle occurring on the Moon.
