Surface water-ice deposits in the northern shadowed regions of Ceres
Surface water-ice deposits in the northern shadowed regions of Ceres
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DOI：
10.1038/s41550-016-0007
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发表时间：
2017-01-01
期刊：
影响因子：
14.1
通讯作者：
Russell, C. T.
中科院分区：
文献类型：
--
作者：
Platz, T.;Nathues, A.;Russell, C. T.
谷神星是一颗位于主小行星带的矮行星，体积密度很低（1），模型预测其地幔和外壳中存在大量的水冰（2-4）。赫歇尔望远镜和黎明号宇宙飞船（5）观测到谷神星释放出水蒸气（6，7），黎明号在中纬度的谷神星表面探测到了暴露的水冰（8）。来自内源和外源的水分子也可以在高纬度（9-11）的永久阴影中被冷捕获，就像月球（12，13）和水星（14，15）一样。在这里，我们提出了第一个基于图像的调查谷神星的北方永久的阴影，并报告发现明亮的存款冷阱。我们确定了至少634个永久阴影陨石坑。在多散射光下，仅在其中10个陨石坑的底部发现了明亮的沉积物。我们用光谱法鉴定出其中一个明亮的沉积物是水冰。这一发现加强了永久阴影区在无空气的行星上保存水冰的证据。
Ceres, a dwarf planet located in the main asteroid belt, has a low bulk density(1), and models predict that a substantial amount of water ice is present in its mantle and outer shell(2-4). The Herschel telescope and the Dawn spacecraft(5) have observed the release of water vapour from Ceres(6,7), and exposed water ice has been detected by Dawn on its surface at mid-latitudes(8). Water molecules from endogenic and exogenic sources can also be cold-trapped in permanent shadows at high latitudes(9-11), as happens on the Moon(12,13) and Mercury(14,15). Here we present the first image-based survey of Ceres's northern permanent shadows and report the discovery of bright deposits in cold traps. We identify a minimum of 634 permanently shadowed craters. Bright deposits are detected on the floors of just 10 of these craters in multi-scattered light. We spectroscopically identify one of the bright deposits as water ice. This detection strengthens the evidence that permanently shadowed areas have preserved water ice on airless planetary bodies.