Abstract
Partitioning of atmophile elements among gas, silicate melt, and molten metallic iron within a growing earth is estimated by using a thermodynamic model based on Kuramoto and Matsui (1996, hereafter called KM96). It is thought that the origin of the atmosphere of the terrestrial planets are (1) capture of nebular gas, (2) degassing by collision of planetesimals before core formation, and (3) late-veneer atmosphere by accretion of oxidative planetesimals after core formation. On the other hand, Hashimoto et al. (2007) made a point of little effect of late-veneer to the formation of atmosphere of terrestrial planets and Genda and Abe (2003) gave suggestions that planetary atmosphere is likely not to thoroughly escape by Giant Impact. In this research, we focus attention on the case (2) that is considered to play a key role to atmosphere formation by modifying the model of KM96.KM96 didn't consider differentiation of iron settling and degassing. Therefore, we took into account the differentiation of three phases, and the effect of planetary accretion to consider more realistic condition.
