title: Lunar atmosphere. How surface composition and meteoroid impacts mediate sodium and potassium in the lunar exosphere.
abstract: Despite being trace constituents of the lunar exosphere, sodium and potassium are the most readily observed species due to their bright line emission. Measurements of these species by the Ultraviolet and Visible Spectrometer (UVS) on the Lunar Atmosphere and Dust Environment Explorer (LADEE) have revealed unambiguous temporal and spatial variations indicative of a strong role for meteoroid bombardment and surface composition in determining the composition and local time dependence of the Moon's exosphere. Observations show distinct lunar day (monthly) cycles for both species as well as an annual cycle for sodium. The first continuous measurements for potassium show a more repeatable variation across lunations and an enhancement over KREEP (Potassium Rare Earth Elements and Phosphorus) surface regions, revealing a strong dependence on surface composition.
authors.affiliation: Space Science Division, NASA Ames Research Center, Moffett Field, Mountain View, CA, USA. anthony.colaprete-1@nasa.gov.
authors.forename: A
authors.initials: A
authors.lastname: Colaprete
authors.affiliation: Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD, USA. University of Maryland, Baltimore County, Baltimore, MD, USA.
authors.forename: M
authors.initials: M
authors.lastname: Sarantos
authors.affiliation: Space Science Division, NASA Ames Research Center, Moffett Field, Mountain View, CA, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Wooden
authors.affiliation: Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Stubbs
authors.affiliation: Space Science Division, NASA Ames Research Center, Moffett Field, Mountain View, CA, USA. Millennium Engineering and Integration Services, Moffett Field, CA 94035, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Cook
authors.affiliation: Space Science Division, NASA Ames Research Center, Moffett Field, Mountain View, CA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Shirley