Widespread distribution of OH/HO on the lunar surface inferred from spectral data.

Remote sensing data from lunar orbiters have revealed spectral features consistent with the presence of OH or HO on the lunar surface. Analyses of data from the Moon Mineralogy Mapper spectrometer onboard the Chandryaan-1 spacecraft have suggested that OH/HO is recycled on diurnal timescales and persists only at high latitudes. However, the spatial distribution and temporal variability of the OH/HO, as well as its source, remain uncertain. Here we incorporate a physics-based thermal correction into analysis of reflectance spectra from the Moon Mineralogy Mapper and find that prominent absorption features consistent with OH/HO can be present at all latitudes, local times, and surface types examined. This suggests the widespread presence of OH/HO on the lunar surface without significant diurnal migration. We suggest that the spectra are consistent with the production of OH in space weathered materials by the solar wind implantation of H and formation of OH at crystal defect sites, as opposed to HO sourced from the lunar interior. Regardless of the specific composition or formation mechanism, we conclude that OH/HO can be present on the Moon under thermal conditions more wide-ranging than previously recognized.