On the relationship between early solar activity and the evolution of terrestrial planet atmospheresMass fractionation during hydrodynamic escape of hydrogen-rich primordial atmospheres form Venus, earth, and Mars can account for most of the salient features of mass distributions in their present-day atmospheres. The principal assumptions and results of an escape-fractionation model for the evolution of terrestrial planet atmospheres from primary to final states are qualitatively described, with emphasis on the astrophysical conditions needed to enable the loss process. A substantial and rapidly declining flux of energetic solar radiation into atmospheric exospheres is required, initially (at solar ages of about 1-10 million years) two to three orders of magnitude more intense than that supplied by extreme-ultraviolet emission from the contemporary sun. The solar accretion disk must have dissipated if such radiation is to penetrate the system midplane to planetray distances. On both criteria, hydrodynamic escape from planets appears plausible in the astrophysical environment of the naked T-Tauri stars.
Document ID
19900044199
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Repin, Robert O. (Minnesota, University Minneapolis, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1989
Subject Category
Lunar And Planetary Exploration
Meeting Information
Meeting: Formation and Evolution of Planetary Systems