Escape of atmospheres and loss of waterThe properties and limitations of several loss processes for atmospheric gases are presented and discussed. They include thermal loss (Jeans and hydrodynamic); nonthermal loss (all processes involve charged particles); and impact erosion, including thermal escape from a molten body heated by rapid accretion. Hydrodynamic escape, or 'blowoff', is of particular interest because it offers the prospect of processing large quantities of gas and enriching the remainder in heavy elements and isotopes. In a second part, the water budgets and likely evolutionary histories of Venus, Earth and Mars are assessed. Although it is tempting to associate the great D/H enrichment on Venus with loss of a large initial endowment, a steady state with juvenile water (perhaps from comets) is equally probable.
Document ID
19890056416
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Hunten, D. M. (Arizona, University Tucson, United States)
Donahue, T. M. (Arizona Univ. Tucson, AZ, United States)
Walker, J. C. G. (Michigan, University Ann Arbor, United States)
Kasting, J. F. (NASA Ames Research Center Moffett Field, CA, United States)