Science2014-06-11 12:48 PM

由卡西尼飞船捕捉到的土卫二地下海洋 The Gravity Field and Interior Structure of Enceladus

论文摘要 

来自卡西尼太空船的新结果显示,土卫二(Enceladus)在18-24英里(30-40公里)厚的冰层下面含有大量的水;卡西尼太空船在过去的10年中一直在土星的各个卫星之间穿梭;而土卫二是土星的较小的卫星之一。Luciano Iess及其同事用三次卡西尼飞越该卫星的多普勒数据来确定土卫二的重力场,并探索其南北半球之间的引人注目的不对称性;这三次飞越将卡西尼飞船带入到了距土卫二表面62英里(100公里)的范围之内。基于他们的分析,研究人员提出,土卫二南极区域的表面没有足够的质量可解释其南半球的重力场,而某些位于该卫星表面之下的东西——也许是液态水——肯定起到了弥补性的作用。他们提出,一个集中在该卫星南半球表层下方的海洋一直延伸到约南纬50度。他们还提出,土卫二是一个分化的卫星,它有一个低密度的核心及一个分开的幔与壳。他们的发现可帮助解释在2005年第一次观察到的从该卫星南极区域独特的、被称为“虎纹”的裂缝中喷射出的富含矿物质的水蒸气流。

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