Origin of Planetary Characteristics
As a planetary scientist, I have been conducting research on how characteristics of planets were formed. Earth has oceans, and life was born and evolved there, which are the unique characters of our Earth. On the other hand, Venus has no ocean and a massive atmosphere, which is quite different surface environment from Earth in spite of similar sized planets. Why did Earth and Venus evolve so differently? Among 8 planets in our solar system, there are wide varieties in their size, composition, satellites, and surface environment. I expect that those fundamental features were characterized during planet formation. Therefore, I have focused on planet formation and their early evolution. In this talk, I will highlight some research achievements of mine that are related to the following three long-term (~ 5 years) research plans. (1) Developing general-purpose impact code and uniting communities of impact modeling and impact experiments. The process of planet formation is the very history of collisions, which definitely characterized planets and their early surface environments. (2) Establishing a science center for planetary exploration. Starting from near future JAXA's Martian moons sample return mission, we discuss science of future Mars mission here at ELSI, and propose those to future planetary missions. (3) Conducting "Aqua planetology", where we try to understand comprehensively how water affects the formation and evolution of planets and pre-life environments. I am leading one of the 5 groups that were funded by MEXT KAKENHI Scientific Research on Innovative Areas in 2017. My group constructs theoretical models of water and material cycles on planetary bodies by incorporating chemical processes revealed by another groups.