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The ancient oxygen exosphere of Mars - Implications for atmosphere evolutionThe paper considers absorption of oxygen (atoms and ions) by the surface as a mechanism for the early Martian atmosphere escape, due to the effect of high EUV flux of the ancient sun. Hot oxygen exosphere densities in ancient atmosphere and ionosphere are calculated for different EUV fluxes and the escape fluxes associated with these exposures. Using these densities, the ion production rate above the ionopause is calculated for different epochs including photoionization, charge exchange, and solar wind electron impact. It is found that, when the inferred high solar EUV fluxes of the past are taken into account, oxygen equivalent to that in several tens of meters of water, planet-wide, should have escaped Martian atmosphere to space over the last 3 Gyr.
Document ID
19930060265
Document Type
Reprint (Version printed in journal)
Authors
Zhang, M. H. G.
(Austrian Academy of Sciences, Space Research Inst., Graz, Austria; California Univ. Los Angeles, United States)
Luhmann, J. G.
(California Univ. Los Angeles, United States)
Bougher, S. W.
(Arizona Univ. Tucson, United States)
Nagy, A. F.
(Michigan Univ. Ann Arbor, United States)
Date Acquired
August 16, 2013
Publication Date
June 25, 1993
Publication Information
Publication: Journal of Geophysical Research
Volume: 98
Issue: E6
ISSN: 0148-0227
Subject Category
Lunar And Planetary Exploration
Accession Number
93A44262
Funding Number(s)
CONTRACT_GRANT: NAG2-491
CONTRACT_GRANT: NAGW-2295
Distribution Limits
Public
Copyright
Other

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