Seminars

Lecturer: H. Lammer (AAS)
Date: 2012-06-21 10:30
Place: Aniara

Origin and evolution of terrestrial planetary atmospheres

H. Lammer
Austrian Academy of Sciences
Space Research Institute
Graz
Austria

Abstract
The origin and evolution of the atmospheres of early Venus, Earth, Mars and exosolar super-Earths will be discussed. A focus will be given to the origin and escape of protoatmospheres and further evolution of secondary atmospheres during a planet’s history. It will be shown that the formation age of a terrestrial planet, its mass and size, as well as the lifetime in the EUV-saturated early phase of its host star play a significant role in its atmosphere evolution. Scenarios will be presented which indicate how the early terrestrial planetary atmospheres most likely evolved through the extreme phase of the young Sun. It will also be shown that super-Earths in orbits within the habitable zone of their host stars might have problems to lose nebular- or catastrophically outgassed initial protoatmospheres. In such a case these planets could end up as water worlds with CO2 and hydrogen- or abiotic oxygen-rich upper atmospheres. If an atmosphere of a terrestrial planet evolves to an N2-rich atmosphere too early in its lifetime, the atmosphere may be lost.

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Created 2012-04-19 09:27:22 by Mats Holmström
Last changed 2012-06-21 12:48:12 by Mats Holmström