Special Guest Seminar - spring-2024

May 14, 2024
2 p.m. - 3 p.m.
3814 Geology

Presented By:

• Eiichiro Kokubo - NAOJ

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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 theoretically 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 each other to form planets. We investigate the orbital architecture of planetary systems formed from protoplanet systems by giant impacts using N-body simulations. 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 scaled by the epicycle amplitude for the eccentricity given by the ratio of the two-body surface escape velocity of planets to the Kepler velocity. With this scaling the orbital architecture parameters are independent of the total mass and semimajor axis of planetary systems.