Theoretical modeling of planetesimal formation in protoplanetary disks based on combined effects of disk dynamics and dust coagulation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K20385
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0204:Astronomy, earth and planetary science, and related fields
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Tominaga Ryosuke 国立研究開発法人理化学研究所, 開拓研究本部, 基礎科学特別研究員 (10908338)
• Project Period (FY): 2021-08-30 – 2024-03-31
• Keywords: 原始惑星系円盤 / ダスト / 微惑星 / 流体不安定性

Outline of Final Research Achievements

The purpose of this research is to reveal planetesimal formation, which is a necessary step in the planet-forming process. Conducting numerical simulations and linear analyses, we explored potential feedback process between dust concentration and collisional growth in protoplanetary disks. We showed (1) that coagulation instability promotes dust concentration that accelerates coagulation, (2) that previously proposed instability can operate in the resulting dust-rich regions and cause planetesimal formation, and (3) that smaller-scale instability called streaming instability can also promote dust coagulation.

Free Research Field

理論宇宙物理学

Academic Significance and Societal Importance of the Research Achievements

微惑星がいつ・どこで・どのくらい形成されるかを解明することは，系外惑星の多様性・共通性の起源を理解する上で本質的に重要である．また太陽系小天体の探査から太陽系の歴史に迫る上でも，微惑星形成の理論的理解は必須である．従来，微惑星形成機構として有力な不安定性の研究が数多く行われてきたが，多くの場合大きく成長した大量のダストが仮定されていた．本研究成果は，ダスト成長の初期段階と従来の不安定性による微惑星形成を橋渡しする点で意義深い．また衝突成長とダスト集積の相乗効果によって，衝突破壊などの問題が回避され得ることを示すことができた．