Accurate and quantitative modeling of the formation of terrestrial planet and the origin of Earth's water

Presenter: Nader HAGHIGHIPOUR
It is widely accepted that collisions among solid bodies, ignited by interactions with planetary embryos is the key process in the formation of terrestrial planets and transport of volatiles to their accretion zones. Unfortunately, these collisions are often treated in a rudimentary way where the impacts are considered to be perfectly inelastic and volatiles to be fully transferred from one object to the other. This perfect-merging assumption has profound effects on the mass and composition of final bodies as it grossly overestimates their masses and volatiles. We have developed a new and comprehensive methodology to simulate growth of embryos to planetary bodies where we use a combination of SPH and N-body codes to accurately model collisions as well as the transport/transfer of chemical compounds. Our methodology accounts for the loss of volatiles during the orbital evolution of their carriers and accurately tracks their transfer from one body to another. Results show that traditional N-body modeling overestimates the amount of the mass and water contents of the final planets by over 60%, far from being realistic. Result also indicate that small planets such as Mars are not anomalies and can form naturally when collisions are treated properly.