[M-GI30] Computational sciences on the universe, galaxies, stars, planets and their environments

[MGI30-04] Unified N-body simulation of planet formation from planetesimal disk: The dynamic planet formation with planetary migration

*Tenri Jinno¹, Takayuki Saitoh¹, Yoko Funato², Junichiro Makino¹ (1.Kobe University, 2.The University of Tokyo)

Keywords:planets and satellites: formation, planet-disk interactions, methods: numerical

In the standard theory of planet formation, planets are thought to form “in-situ” around their current orbits. Planet formation starts when a slightly larger planetesimal in the planetesimal disk undergoes runaway growth. This runaway growth happens concurrently across different regions of the disk, leading to the in-situ oligarchic growth of multiple planetary embryos. These embryos subsequently evolve into terrestrial planets, as well as the cores of gas and ice giants, ultimately forming planetary systems. Although this theory naturally explains how our Solar System formed, it faces difficulties in accounting for the wide variety of exoplanetary systems which requires dynamic planetary migration.
Here we perform the unified self-consistent N-body simulations of planet formation from a large-scale planetesimal disk within the framework of the conventional smoothed planetesimal disk in which we take into account planet-disk gas interactions, planet-planetesimal interactions, and gravitational interactions among all planetesimals. Our results show that planets dynamically migrate both inward and outward from the runaway growth stage. The results of our simulations suggest that even within the framework of the classical smoothed planetesimal disk expressed as a Hayashi model, the core accretion model does not support the conventional views of in-situ and oligarchic growth of planetary embryos. Instead, dynamic migration begins from the early runaway growth phase. Consequently, the position of each embryo has a wide variety when the oligarch growth stage begins. Our results show that the dynamic planetary migration required to explain the diversity of exoplanetary systems naturally takes place without any exotic initial conditions and so on.