The dust halo of Saturn's largest icy moon, Rhea
The dust halo of Saturn's largest icy moon, Rhea
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DOI：
10.1126/science.1151524
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发表时间：
2008-03-07
期刊：
影响因子：
56.9
通讯作者：
Young, D.
中科院分区：
文献类型：
--
作者：
Jones, G. H.;Roussos, E.;Young, D.
土星的卫星土卫五被认为质量足够大，可以保持一个薄的外部产生的大气层，能够局部影响土星的磁层。卡西尼号飞船的现场观测显示，月球附近的高能电子已经耗尽。没有大量的外逸层意味着土卫五的磁层相互作用区域，而不是完全由溅射气体及其产物引起的，可能含有可以吸收磁层粒子的固体物质。几种仪器的综合观测表明，这种物质是以颗粒和巨石的形式存在的，大小可达几分米，并作为赤道碎片盘绕土卫五轨道运行。在这个圆盘中可能存在着更致密的、离散的物质环或弧。
Saturn's moon Rhea had been considered massive enough to retain a thin, externally generated atmosphere capable of locally affecting Saturn's magnetosphere. The Cassini spacecraft's in situ observations reveal that energetic electrons are depleted in the moon's vicinity. The absence of a substantial exosphere implies that Rhea's magnetospheric interaction region, rather than being exclusively induced by sputtered gas and its products, likely contains solid material that can absorb magnetospheric particles. Combined observations from several instruments suggest that this material is in the form of grains and boulders up to several decimetres in size and orbits Rhea as an equatorial debris disk. Within this disk may reside denser, discrete rings or arcs of material.