Is planetary formation possible from sintered aggregates? Laboratory experiment and numerical simulation

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K05631
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Nagoya University
• Principal Investigator: SIRONO Sin-iti 名古屋大学, 環境学研究科, 准教授 (20332702)
• Co-Investigator(Kenkyū-buntansha): 桂木 洋光 名古屋大学, 環境学研究科, 准教授 (30346853)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: ダストアグリゲイト / 焼結 / 微惑星 / 形成場所

Outline of Final Research Achievements

Mechanical properties of dust aggregates strongly affect the first step of planetary formation. If elasticity of an aggregate is large, the collisioncal outcome of aggregates becomes bouncing and growth to planets is prohibited. In this study, elasticity between dust grains was determined as a function of the degree of sintering, which is an efficient mechanism in a protoplanetary nebula. There are four modes of deformation: 1: stretching 2: rolling 3: sliding 4: stretching. The determined elasticity for stretching was smaller than that in previous model. Empirical formulas were derived for the elasticities. The collisional simulation was conducted to check the effect of the modified elasticity. The collisional outcome of numerical simulation was not changed.

Free Research Field

惑星科学

Academic Significance and Societal Importance of the Research Achievements

焼結したダストアグリゲイトの弾性率を明らかにし，その結果をもとにして数値シミュレーションを行なったところ，衝突の結果が合体から跳ね返りに転じる可能性が非常に高くなることが明らかとなった．ここから，惑星は焼結が起こらない領域でのみ形成しうると考えられる．惑星の形成場所が焼結によって決定さうるということは，原始惑星系円盤の観測結果からも示唆されている．