Saturn's Small Inner Satellites: Clues to Their Origins
Saturn's Small Inner Satellites: Clues to Their Origins
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土星的小型内部卫星：它们起源的线索
DOI：
10.1126/science.1143977
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发表时间：
2007
期刊：
影响因子：
56.9
通讯作者：
D. Richardson
中科院分区：
文献类型：
--
作者：
C. Porco;P. Thomas;J. W. Weiss;D. Richardson
卡西尼号拍摄的土星内部小卫星（半径小于100公里）的图像已经给出了它们的大小，形状，在某些情况下，地形和平均密度。这些信息和数值N体模拟的吸积生长提供了线索，他们的内部结构和起源。最里面的环区卫星可能通过在致密的核心周围吸积物质而增长到最大尺寸，大约是目前月球尺寸的三分之一到一半。环外的其他小卫星可能接近于单一的碰撞碎片，被吸积改变了不同程度，或者可能是在没有核心的帮助下通过吸积生长的。我们推导出的粘度值为87和20平方厘米每秒，分别为环包埋潘和Daphnis周围的环材料。这些卫星几乎肯定会打开各自的间隙，然后在早期增长到现在的大小，当时当地的环环境比今天更厚。
Cassini images of Saturn's small inner satellites (radii of less than ∼100 kilometers) have yielded their sizes, shapes, and in some cases, topographies and mean densities. This information and numerical N-body simulations of accretionary growth have provided clues to their internal structures and origins. The innermost ring-region satellites have likely grown to the maximum sizes possible by accreting material around a dense core about one-third to one-half the present size of the moon. The other small satellites outside the ring region either may be close to monolithic collisional shards, modified to varying degrees by accretion, or may have grown by accretion without the aid of a core. We derived viscosity values of 87 and 20 square centimeters per second, respectively, for the ring material surrounding ring-embedded Pan and Daphnis. These moons almost certainly opened their respective gaps and then grew to their present size early on, when the local ring environment was thicker than it is today.