Geological processes under an extremely small gravity : Effects of seismic-shaking

对隼鸟号飞船获得的特写图像进行详细的地质研究表明，一些砾石上有亮点，这表明表面块体的年龄为1-10Ma。这支持了我们的观点，即表面砾石偶尔会在小行星Itokawa表面迁移。我们开发了不规则形状的三维岩石颗粒的数值模拟代码，发现隼鸟号飞船获得的特写图像中的砾石具有几何饱和，因此它们的尺寸-频率分布应该仔细用于讨论Itokawa的内部结构。此外，我们还建立了包括静电悬浮微粒在内的砾石迁移的理论模型。我们的理论模型表明，土星卫星阿特拉斯的光滑可以用尘埃悬浮来解释，这可能是这颗卫星表面的主要重铺过程。这表明，在极小的重力下，尘埃悬浮可能是另一种重要的全球尺度重铺。

Detailed geological study of close-up images obtained by Hayabusa spacecraft reveal that some of the gravels hold bright spot, which indicate the age of surface blocks is 1-10Ma. This supports our view that the surface gravel is migrating occasionally on the surface of the asteroid Itokawa. We developed a numerical simulation code of three-dimensional rock particles with irregular shapes and find that the gravels in the close-up images obtained by Hayabusa spacecraft are geometrically saturated and thus their size-frequency distributions should be carefully used to discuss the internal structure of Itokawa. Also, we newly develop a theoretical model of migrations of gravels including electro-statically levitated fine particles. Our theoretical model indicates that the smoothness of Saturnian satellite, Atlas, can be explained by dust levitations, which might be the dominant resurfacing process on the surface of this satellite. This indicates that dust levitation can be another important global-scale resurfacing under an extremely small gravity.