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A comparative study of the influence of the active young sun on the early atmospheres of Earth, Venus, and Mars

Kulikov, Y. and Lammer, H. and Lichtenegger, H. and Penz, T. and Breuer, D. and Spohn, T. and Lundin, R. and Biernat, H. (2006) A comparative study of the influence of the active young sun on the early atmospheres of Earth, Venus, and Mars. Space Science Reviews, 129 (1-3), pp. 207-243. Springer. DOI: 10.1007/s11214-007-9192-4. ISSN 0038-6308.

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Abstract

Because the solar radiation and particle environment plays a major role in all atmospheric processes such as ionization, dissociation, heating of the upper atmospheres, and thermal and non-thermal atmospheric loss processes, the long-time evolution of planetary atmospheres and their water inventories can only be understood within the context of the evolving Sun. We compare the effect of solar induced X-ray and EUV (XUV) heating on the upper atmospheres of Earth, Venus and Mars since the time when the Sun arrived at the Zero-Age-Main-Sequence (ZAMS) about 4.6 Gyr ago. We apply a diffusive-gravitational equilibrium and thermal balance model for studying heating of the early thermospheres by photodissociation and ionization processes, due to exothermic chemical reactions and cooling by IR-radiating molecules like CO<sub>2</sub>, NO, OH, etc. Our model simulations result in extended thermospheres for early Earth, Venus and Mars. The exospheric temperatures obtained for all the three planets during this time period lead to diffusion-limited hydrodynamic escape of atomic hydrogen and high Jeans’ escape rates for heavier species like H<sub>2</sub>, He, C, N, O, etc. The duration of this blow-off phase for atomic hydrogen depends essentially on the mixing ratios of CO<sub>2</sub>, N<sub>2</sub> and H<sub>2</sub>O in the atmospheres and could last from ∼100 to several hundred million years. Furthermore, we study the efficiency of various non-thermal atmospheric loss processes on Venus and Mars and investigate the possible protecting effect of the early martian magnetosphere against solar wind induced ion pick up erosion. We find that the early martian magnetic field could decrease the ion-related non-thermal escape rates by a great amount. It is possible that non-magnetized early Mars could have lost its whole atmosphere due to the combined effect of its extended upper atmosphere and a dense solar wind plasma flow of the young Sun during about 200 Myr after the Sun arrived at the ZAMS. Depending on the solar wind parameters, our model simulations for early Venus show that ion pick up by strong solar wind from a non-magnetized planet could erode up to an equivalent amount of ∼250 bar of O<sup>+</sup> ions during the first several hundred million years. This accumulated loss corresponds to an equivalent mass of ∼1 terrestrial ocean (TO (1 TO ∼1.39×10<sup>24</sup> g or expressed as partial pressure, about 265 bar, which corresponds to ∼2900 m average depth)). Finally, we discuss and compare our findings with the results of preceding studies.

Document Type:Article
Additional Information:Online-Veröffentlichung
Title:A comparative study of the influence of the active young sun on the early atmospheres of Earth, Venus, and Mars
Authors:
AuthorsInstitution or Email of Authors
Kulikov, Y.Polar Geophysical Institute (PGI), Russian Academy of Sciences, Khalturina Str. 15, 183010 Murmansk, Russian Federation
Lammer, H.Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
Lichtenegger, H.Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
Penz, T.Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
Breuer, D.UNSPECIFIED
Spohn, T.UNSPECIFIED
Lundin, R.Swedish Institute of Space Physics (IRF), P.O. Box 812, 98128 Kiruna, Sweden
Biernat, H.Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
Date:2006
Journal or Publication Title:Space Science Reviews
Refereed publication:Yes
In ISI Web of Science:Yes
Volume:129
DOI:10.1007/s11214-007-9192-4
Page Range:pp. 207-243
Publisher:Springer
ISSN:0038-6308
Status:Published
Keywords:Early atmospheres; Atmospheric evolution; Thermospheric heating; Solar induced atmospheric loss
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EW - Erforschung des Weltraums
DLR - Research area:Space
DLR - Program:W EW - Erforschung des Weltraums
DLR - Research theme (Project):W - Vorhaben Vergleichende Planetologie (old)
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Physics
Deposited By: Stefanie Musiol
Deposited On:14 Jan 2008
Last Modified:15 Jan 2010 00:21

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