Pham, L. B. S. ; Karatekin, Ö. ; Dehant, V.

Poster presented at 9th European Workshop on Astrobiology on 2009-10-12

Abstract: Early in its history, the planets probably had denser atmospheres; Mars for instance had likely an atmosphere with sufficient greenhouse gases for sustaining the presence of stable liquid water at the surface. Impacts by asteroids and comets could have played a significant role in the evolution of the early atmospheres of the Earth, Mars and Venus, not only by causing atmospheric erosion but also by delivering material and volatiles to the planets. We investigate the atmospheric loss and the delivery of volatiles using an analytical model that takes into account the impact simulation results and the flux of impactors given in the literature. The atmospheric loss and the delivery of volatiles are calculated in order to obtain the atmospheric pressure evolution. Our results are compared for the three planets. We have also considered in our scenario, a period with intense bombardment of meteorites that could have increased the atmospheric loss and/or replenishment at the beginning of the history of the terrestrial planets.

Keyword(s): Mars ; Venus ; Earth ; Astrobiology ; Impacts ; Asteroids