Recent observations of the potentially habitable planets TRAPPIST-1 e, f, and g suggest that they possess large water mass fractions of possibly several tens of weight percent of water, even though the host star's activity should drive rapid atmospheric escape. These processes can photolyze water, generating free oxygen and possibly desiccating the planet. After the planets formed, their mantles were likely completely molten with volatiles dissolving and exsolving from the melt. To understand these planets and prepare for future observations, the magma ocean phase of these worlds must be understood. To simulate these planets, we have combined existing models of stellar evolution, atmospheric escape, tidal heating, radiogenic heating, magma-ocean cooling, planetary radiation, and water-oxygen-iron geochemistry. We present , a versatile magma-ocean evolution model, validated against the rocky super-Earth GJ 1132b and early Earth. We simulate the coupled magma-ocean atmospheric evolution of TRAPPIST-1 e, f, and g for a range of tidal and radiogenic heating rates, as well as initial water contents between 1 and 100 Earth oceans. We also reanalyze the structures of these planets and find they have water mass fractions of 0–0.23, 0.01–0.21, and 0.11–0.24 for planets e, f, and g, respectively. Our model does not make a strong prediction about the water and oxygen content of the atmosphere of TRAPPIST-1 e at the time of mantle solidification. In contrast, the model predicts that TRAPPIST-1 f and g would have a thick steam atmosphere with a small amount of oxygen at that stage. For all planets that we investigated, we find that only 3–5% of the initial water will be locked in the mantle after the magma ocean solidified.

中文翻译：

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TRAPPIST-1 行星的岩浆海洋演化

最近对潜在宜居行星 TRAPPIST-1 e、f 和 g 的观察表明，它们拥有大量的水质量分数，可能占水的几十重量百分比，尽管主星的活动应该会推动大气快速逃逸。这些过程可以光解水，产生游离氧并可能使地球干燥。行星形成后，它们的地幔很可能完全熔化，挥发物从熔体中溶解和析出。为了了解这些行星并为未来的观测做好准备，必须了解这些世界的岩浆海洋阶段。为了模拟这些行星，我们结合了现有的恒星演化、大气逃逸、潮汐加热、辐射加热、岩浆-海洋冷却、行星辐射和水-氧-铁地球化学模型。我们提出，一种多功能的岩浆海洋演化模型，已针对岩石超级地球 GJ 1132b 和早期地球进行了验证。我们模拟了 TRAPPIST-1 e、f 和 g 在一系列潮汐和放射性加热速率以及 1 到 100 个地球海洋之间的初始含水量的耦合岩浆-海洋大气演化。我们还重新分析了这些行星的结构，发现行星 e、f 和 g 的水质量分数分别为 0-0.23、0.01-0.21 和 0.11-0.24。我们的模型没有对地幔凝固时 TRAPPIST-1 e 大气中的水和氧含量做出强有力的预测。相比之下，该模型预测 TRAPPIST-1 f 和 g 在该阶段将具有带有少量氧气的浓蒸汽气氛。对于我们调查的所有行星，