Abstract
Chemical products within impact-induced vapor clouds are thought to have affected the surface environments of planets. However, chemical reactions within vapor clouds are very complicated and are not well understood. In particular, chemical interaction between silicates and carbon compounds has not been studied extensively. In previous work, we have confirmed experimentally that oxygen derived from SiO2 reacts with carbon compounds. Though the effect of SiO2 is ignored in previous theoretical studies, the result indicated that the effect of SiO2 should be considered. In this study, we perform thermodynamic equilibrium calculation using a composition of C, H, O, and Si, which stands for the reaction systems including SiO2. We calculate along adiabatic P-T paths of vapor clouds to investigate the effect of SiO2 on the molecular composition of gases. The results show that the oxidation by SiO2-derived oxygen and the molecular composition of produced gases are strongly affected by the impact velocity. In particular, the amount of CH4, which is important for the origin of life or warming of paleo-Mars, is strongly affected by the impact velocity.
