2021 Fiscal Year Final Research Report

Constructing a standard formation model of satellites around gas giant planets

Research Project

PDF

Project/Area Number	15H02065
Research Category	Grant-in-Aid for Scientific Research (A)
Allocation Type	Single-year Grants
Section	一般
Research Field	Astronomy
Research Institution	Tokyo Institute of Technology
Principal Investigator	Ida Shigeru 東京工業大学, 地球生命研究所, 教授 (60211736)
Co-Investigator(Kenkyū-buntansha)	木村淳大阪大学, 理学研究科, 助教 (00536138) 谷川享行一関工業高等専門学校, その他部局等, 准教授 (30422554) 奥住聡東京工業大学, 理学院, 准教授 (60704533) 佐々木貴教京都大学, 理学研究科, 助教 (70614064)
Project Period (FY)	2015-04-01 – 2020-03-31
Keywords	惑星の衛星形成 / 惑星形成 / 惑星探査
Outline of Final Research Achievements	Toward construction of a standard theoretical model for moon formation around general gas giant planets, which has not been addressed, we performed state-of-arts fluid dynamical, gravitational N-body, and statistical Monte Carlo simulations. Using the simulation results of gas inflow to a circumplanetary disk, we suggested the growth mode of a solid core in a gas giant. Through N-body simulations, we showed that orbit crossing occurred between Enceladus, a Saturnian moon, and other moons and the associated tidal heating is enough to maintain Enceladus geyser activity with assistance of the moon-ring gravitational interactions. Based in these results, we published a review article on current understanding of Saturnian moon formation in Science. We also showed that the orbital configurations and chemical compositions of Galilean moons are reproduced if a modern model of a circumplanetary disk is used.
Free Research Field	惑星科学
Academic Significance and Societal Importance of the Research Achievements	これまでの衛星形成の研究は衛星だけを見ていたが、衛星形成は惑星形成の一部であり、我々は惑星形成の文脈で惑星周円盤のモデルを考えた。また、衛星形成は多段階過程であり、各基礎過程の徹底解析のもとにそれらを組み上げる方法論は、太陽系形成「京都モデル」以来の日本の伝統であるが、国際的には極めてユニークである。この方法論のもと、巨大ガス惑星の衛星形成の新たな理論モデルの一部を構築した。新たなモデル構築の意義の他、巨大ガス惑星の衛星は、惑星地質学、太陽系・系外惑星系形成論、宇宙生物学などと接点を持ち、その標準モデル構築の波及効果は大きい。