Characterizing the hydroxyl observation of the LCROSS UV-visible spectrometer: Modeling of the impact plume.

Lunar Crater Observation and Sensing Satellite (LCROSS) impacted the Cabeus crater near the lunar South Pole on 9 October 2009 and generated an impact plume. The hydroxyl (OH) band strength observations obtained from the LCROSS mission are explained with the help of numerical modeling of the impact plume. We provide different models of OH production in the plume and conduct a parametric study to constrain the independent parameters of these models. In particular, detailed lofted grain heating, sublimation and photodissociation models are implemented along with models for H2O and OH production from the residual impact crater. Results show that the likely sources of observed OH are from a small amount of direct/abrasional OH desorption from regolith grains (~28 g) in the crater and from sublimation of water vapor (O (800 kg)) from lofted regolith-imbued ice grains followed by photodissociation. [ABSTRACT FROM AUTHOR]