| Project/Area Number |
12640405
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体地球物理学
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
NAKAZAWA Kiyoshi Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Professor, 大学院・理工学研究科, 教授 (10025455)
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| Co-Investigator(Kenkyū-buntansha) |
EMORI Hiroyuki Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Research Associate, 大学院・理工学研究科, 助手 (30262257)
IDA Shigeru Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Assiociate Professor, 大学院・理工学研究科, 助教授 (60211736)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Origin of the Moon / Giant Impact / N-body / SPH Fluid Dynamics / Satellite / 月物質 / 地球の起源 / SPH流体計算 / 角運動量 / 巨大衝突説 / 密度波 / コンピューター・シミュレーション / 非弾性衝突 / 重力相互作用 |
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| Research Abstract |
The giant impact between a Mars size proto-planet and the Earth could produce the moon. This is the model of moon formation called "The Giant Impact Model". Today many scientists studying about the origin of the moon consider the model the most reliable one. In this study we investigated the model in two parts for two years. First part is study about the giant impact it self. Second is the accumulation process of the moon from the disk around the Earth.
The accumulation of the moon in the circum earth disk was supported by strong mass transfer due to the axis-asymmetric gravitational field produced by density waves in the disk. The gravitational field carried the rock debris outer than the Roche limits. Then the debris accumulated to the single moon. We have confirmed the transfer process by N-body numerical simulation and formulate the transfer rate as a function of initial disk mass theoretically. In addition to that, we found that initially light disk could produce multiple moonlets
… More
outside the Roche limits and initially heavy one could produce massive single moon. So, we estimate the initial disk mass of the Earth which has single moon as heavier than 3 times the mass of the moon.
The giant impacts between proto-planets could take place very frequently in the planetary formation process. So, it is important to investigate the impacts not only as the moon formation stage but also one of the important basic process in the planetary formation. We have investigated the giant impact process under the wide range of impact parameters rather than to concentrate on the moon formation process only. From the studies we have found that the proto planet deformed significantly at the impact instance, but the proto planet restore its global figure by its strong self gravity. In addition to that we confirmed that the restored proto planet was on the oval orbit around the Earth which never produces the giant impact any more. This fact implies that the giant impact process could play a role resemble to the "Capture process" in the moon formation. Less
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