Observations of potassium in the tenuous lunar atmosphere

• Published in: Geophysical research letters Vol. 17; no. 12; pp. 2253 - 2256
• Main Authors: Kozlowski, Richard W. H., Sprague, Ann L., Hunten, Donald M.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS Blackwell Publishing Ltd 01.11.1990
• Subjects: 640107 - Astrophysics & Cosmology- Planetary Phenomena; ALKALI METALS; ARGON; ATMOSPHERES; CHEMICAL COMPOSITION; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Density; EARTH PLANET; ELEMENTS; EMISSION SPECTRA; FLUIDS; GASES; Geophysics; HELIUM; HYDROGEN; IONIZATION; Lunar And Planetary Exploration; Mathematical models; METALS; NEON; NONMETALS; ORIGIN; PHOTOIONIZATION; PLANETS; POTASSIUM; RADIATIONS; RADON; RARE GASES; SATELLITE ATMOSPHERES; Scale height; SLOWING-DOWN; SOLAR ACTIVITY; SOLAR RADIATION; SOLAR WIND; SPECTRA; STELLAR RADIATION; Surface chemistry; Surface temperature; THERMALIZATION; Velocity distribution
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/GL017i012p02253

Observations of neutral potassium (K) in the tenuous lunar atmosphere are described. An echelle spectrograph, CCD, and data acquisition system are used to obtain emission spectra of neutral K atoms in the lunar atmosphere as observed by the 1.54 telescope at the Catalina Observatory at first quarter the night of April 29, 1989. A table of relevant lunar atmosphere parameters summarizes the results of the investigation. It is found that the number density at the surface is 9.5 + or - 1 atoms per cu cm and that there is a large nonthermal component and a deficiency of atoms equilibrated to the surface temperature. The calculated thermalization rate of the nonthermal component through encounters with the lunar surface gives a source of strength for the thermal component factor of 7 greater than loss by photoionization. Possible explanations for the low thermalized population observed are considered.