首页

In the standard formation models of terrestrial planets in the solar system and close-in super-Earths recently discovered by exoplanet observations, planets are formed by giant impacts of protoplanets or planetary embryos after the dispersal of protoplanetary disk gas in the final stage. This study aims to clarify a fundamental scaling law for the orbital architecture of planetary systems formed by giant impacts. In the giant impact stage, protoplanets gravitationally scatter and collide with one another to form planets. Using N-body simulations, we investigate the orbital architecture of planetary systems formed from protoplanet systems by giant impacts. As the orbital architecture parameters, we focus on the mean orbital separation between two adjacent planets and the mean orbital eccentricity of planets in a planetary system. We find that the orbital architecture is determined by the ratio of the two-body surface escape velocity of  planets to the Keplerian circular velocity. The ratio can scale the mean orbital separation and eccentricity of planetary systems.

BIO

Eiichiro Kokubo,Professor, Division of Science, National Astronomical Observatory of Japan (NAOJ); Director, Center for Computational Astrophysics (CfCA). Concurrent Professor, Department of Astronomy, Graduate School of Science, The University of Tokyo. Received a Ph.D. from The University of Tokyo, in 1997. His research field is formation of planetary systems. He aims to elucidate the fundamental processes of planet formation through theoretical studies and numerical simulations, and to reveal the origins of the diversity of planetary systems.

Host: Wei Zhu