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Electron spectroscopic studies related to solar‐wind darkening of the lunar surface
Author(s) -
Yin Lo I,
Tsang Tung,
Adler Isidore
Publication year - 1975
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl002i001p00033
Subject(s) - solar wind , fayalite , silicate , ion , helium , spectrometer , proton , materials science , astrobiology , atomic physics , physics , mineralogy , geology , astronomy , plasma , nuclear physics , olivine , optics , quantum mechanics
Improved instrumentation in the x‐ray photoelectron spectrometer allowed the first direct observation of the change of valence state of iron in the silicate Fayalite under helium‐ion bombardment. From the observed ion dosage necessary to reduce the iron in the topmost atomic layers to the metallic state it is estimated that similar reduction on the lunar surface under solar‐wind proton bombardment would occur between 700 to 1000 years. Within such a time scale, it seems likely that all surface iron in the iron‐containing lunar fines should have been reduced to the metallic state. Implications of these experimental observations in terms of various proposed darkening mechanisms are discussed.