巨大衝突に始まる月形成:岩石破片円盤形成から揮発性物質散逸まで

火星大小的原行星与地球之间的巨大撞击可能产生月球。这是月球形成的模型，被称为“大碰撞模型”。今天，许多研究月球起源的科学家认为这个模型是最可靠的。在本研究中，我们分两部分对该模型进行了为期两年的研究。第一部分是对其自身巨大影响的研究。第二个是月球从环绕地球的圆盘聚集的过程。月球在环地球盘上的积累是由环地球盘上密度波产生的轴不对称引力场所导致的强传质所支持的。引力场将岩石碎屑带出罗氏极限之外。然后这些碎片堆积到单一的月球上。我们通过n体数值模拟证实了传递过程，并从理论上将传递速率表示为初始圆盘质量的函数。除此之外，我们还发现，最初较轻的圆盘可以产生多个卫星，超过罗氏极限的圆盘和最初较重的圆盘可以产生巨大的单个卫星。所以，我们估计地球的初始圆盘质量只有一个月球，比月球质量的3倍还要重。在行星形成过程中，原行星之间的巨大碰撞可能会非常频繁地发生。因此，研究撞击不仅是月球形成阶段，也是行星形成的重要基础过程之一，具有重要意义。我们在大范围的撞击参数下研究了巨大的撞击过程，而不是只关注月球的形成过程。从研究中我们发现，原行星在撞击时发生了明显的变形，但原行星凭借其强大的自我引力恢复了其整体形状。除此之外，我们还证实，修复后的原行星在地球周围的椭圆形轨道上，再也不会产生巨大的影响。这一事实表明，巨大的撞击过程可能在月球形成过程中发挥类似于“捕获过程”的作用。少

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