Satellite systems in the Solar System: Origin of their characteristics and diversity

2019 Fiscal Year Final Research Report

• Project/Area Number: 15H03716
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Kobe University
• Principal Investigator: Ohtsuki Keiji 神戸大学, 理学研究科, 教授 (00250910)
• Co-Investigator(Kenkyū-buntansha): 吉田 二美 千葉工業大学, 惑星探査研究センター, 研究員 (20399306) ; 末次 竜 産業医科大学, 医学部, 助教 (40737334) ; 高遠 徳尚 国立天文台, ハワイ観測所, 教授 (50261152) ; 平田 直之 神戸大学, 理学研究科, 助教 (00791550)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 衛星形成 / 惑星リング / 巨大惑星 / 太陽系小天体 / 惑星形成

Outline of Final Research Achievements

Observations by the Cassini spacecraft brought abundant new insights about the origin and evolution of ring-satellite systems of giant planets. With these new data in hand, we carried out theoretical studies on ring-satellite systems of giant planets. We developed a new model for the origin of Saturn's F ring and its shepherd satellites, and also carried out new simulations for the origin of rings of giant planets as well as rings of Centaurs. We also found that the gas disk around a growing giant planet can capture building blocks of regular satellites, but that it is difficult to explain the origin of irregular satellites by this mechanism alone. In relation to the origin of irregular satellites of giant planets, we also examined surface properties of small bodies in the outer Solar System using data obtained by the Subaru Telescope, and obtained results that support transportation of small icy bodies from the trans-Neptunian region into the giant planet region.

Free Research Field

惑星科学

Academic Significance and Societal Importance of the Research Achievements

土星のFリングは1979年に探査機パイオニア11号により発見されたが、その起源は不明であった。本研究ではこの一見、奇妙に見える環は、土星の周りの衛星形成過程の自然な副産物として説明できることを世界で初めて示し、衛星と環の起源は密接に関連していることを明らかにした。さらに、巨大惑星の環やケンタウルス族天体と呼ばれる小天体の環の起源を考察することにより、環の研究が太陽系進化の解明に大きく貢献し得ることを明らかにした。