Hydrogen has been thought to be an important light element in Earth's core due to possible siderophile behavior during core-mantle segregation. We reproduced planetary differentiation conditions using hydrogen contents of 450 to 1500 parts per million (ppm) in the silicate phase, pressures of 5 to 20 GPa, oxygen fugacity varying within IW-3.7 and IW-0.2 (0.2 to 3.7 log units lower than iron-wüstite buffer), and Fe alloys typical of planetary cores. We report hydrogen metal-silicate partition coefficients of ~2 × 10^-1, up to two orders of magnitude lower than reported previously, and indicative of lithophile behavior. Our results imply H contents of ~60 ppm in the Earth and Martian cores. A simple water budget suggests that 90% of the water initially present in planetary building blocks was lost during planetary accretion. The retained water segregated preferentially into planetary mantles.

中文翻译：

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陆地行星核心中的氢含量低。

氢被认为是地球核心中的重要轻元素，因为在核心-地幔隔离过程中可能存在亲铁性行为。我们通过使用硅酸盐相中的氢含量为450至1500 ppm（百万分之五），压力为5至20 GPa，氧逸度在IW-3.7和IW-0.2之间变化（比铁低0.2至3.7 log单位）来再现行星分化条件-wüstite缓冲剂）和典型的行星芯铁合金。我们报告的氢金属硅酸盐分配系数为〜2×10 ^-1，比以前的报告最多低两个数量级，并指示了亲石行为。我们的结果表明，地球和火星核心中的H含量约为60 ppm。一个简单的水预算表明，最初在行星积木中存在的90％的水在行星积聚过程中流失了。保留的水优先分离成行星地幔。