The lunar exosphere as seen from LADEE UVS

Abstract:

The Lunar Atmosphere and Dust Environment Explorer (LADEE) Ultraviolet Visible Spectrometer (UVS) began commissioning activities in orbit around the moon on October 16, 2013. Science observations began October 23, 2013 and continued until minutes prior to the planned disposal of the LADEE spacecraft on April 18, 2014 (UTC). Over the course of the mission the UVS instrument made a series of systematic observations, including lunar limb stares at both terminators and about local noon, targeted activities, including anti-sun sodium tail observations, north/south limb stares, solar extinction measurements, and instrument calibrations.

Initial analysis of these observations have resulted in temporal and spatial mapping of key exosphere species, such as sodium and potassium, and the detection of several previously-undetected species. Sodium and potassium show variations in concentration across both a single lunation and longer semi-annual periods. These changes are likely due to a response to micro-meteoroidal and solar wind fluxes as well as spatial variations in surface composition. Tentative detections of Ti, Si, Mg, O, Al and He+ have been made. Observations in search of dust, including limb and occultation activities, have provided high signal-to-noise spectra that show variations in extinction and light scattering possibly due to exospheric dust.

This talk will provide an overview of UVS results, with an emphasis on the sodium and potassium observations.