Abstract Giant impacts are disruptive events occurring in the early stages of planetary evolution. They may result in the formation of a protolunar disk or of a synestia. A central planet and one or several moons condense upon cooling bearing the chemical signature of the silicate mantles of the initial bodies; the iron cores may partly vaporize, fragment and/or merge. Here we determine from ab initio simulations the critical point of iron in the temperature range of 9000-9350 K, and the density range of 1.85-2.40 g/cm3, corresponding to a pressure range of 4-7 kbars. This implies that the iron core of the proto-Earth may become supercritical after giant impacts and during the condensation and cooling of the protolunar disk. We show that the iron core of Theia partially vaporized during the Giant Impact. Part of this vapor may have remained in the disk, to eventually participate in the Moon's small core. Similarly, during the late veneer a large fraction of the planetesimals have their cores undergoing partial vaporization. This would help mixing the highly siderophile elements into magma ponds or oceans.

中文翻译：

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从熵和铁的临界点推断出巨大撞击期间的部分核心汽化

摘要 巨行星撞击是发生在行星演化早期阶段的破坏性事件。它们可能导致原月盘或联结的形成。一颗中央行星和一颗或几颗卫星在冷却时凝结，带有初始天体硅酸盐地幔的化学特征；铁芯可能会部分汽化、碎裂和/或合并。在这里，我们通过从头算模拟确定铁在 9000-9350 K 温度范围内的临界点，以及 1.85-2.40 g/cm3 的密度范围，对应于 4-7 kbars 的压力范围。这意味着原地球的铁核在巨大撞击之后以及原月盘的冷凝和冷却过程中可能会变得超临界。我们展示了忒伊亚的铁核在巨大撞击期间部分蒸发。这种蒸气的一部分可能留在圆盘中，最终参与到月球的小核心中。类似地，在晚饰面期间，很大一部分星子的核心经历了部分汽化。这将有助于将高度亲铁元素混合到岩浆池或海洋中。