再充气：氧化还原驱动的大气膨胀作为超级地球地球化学的示踪剂
Reflation: redox-driven atmospheric inflation as tracer of super-Earth geochemistry
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中文总结 AI 辅助
研究超级地球大气演化，发现地幔排气氧化还原敏感性引发再充气事件，通过模拟耦合演化，揭示还原地幔使大气再充气、密度降低，氧化地幔则相反，此差异或可作为内部地球化学和形成条件的示踪剂。
中文摘要 AI 辅助
我们证明，地幔排气的氧化还原敏感性可引发高辐照和地球化学还原的超级地球大气的短暂再充气事件，我们将此机制称为再充气。地幔氧化还原控制着CHONS挥发物的排气和形态，在高辐照条件下的长时间光蒸发过程中设定了背景二次大气组成。通过对辐照超级地球的大气-内部耦合演化进行模拟，我们表明接近铁-方铁矿缓冲剂的还原地幔最初产生以CO为主的大气。流体动力学逃逸不断去除挥发物，而熔体排气则用从下伏岩浆海洋中溶解的H2O转化而来的H2补充大气。这导致从C主导气体到H主导气体的后期转变，该转变会短暂地使超级地球大气再充气，并在其形成后的数百Myr到Gyr之间，在光蒸发完全侵蚀大气之前，使它们的整体密度降低高达约60%。相比之下，更接近地球地球化学的氧化地幔在经历流体动力学逃逸时会强烈缓冲其大气组成，导致半径单调减小。再充气事件由地球化学还原的地幔、中等逃逸效率、高辐照和初始水储量≥5个地球海洋触发。这种依赖氧化还原的演化差异取决于内部和大气演化之间的敏感反馈，可作为历史地球化学状态的潜在示踪剂。因此，近距离超级地球的群体层面再充气特征可作为内部地球化学和形成条件的示踪剂。
英文摘要
We demonstrate that the redox-sensitivity of mantle outgassing can trigger transient episodes of atmospheric re-inflation in highly irradiated and geochemically-reduced super-Earths, a mechanism we term reflation. Mantle redox governs the outgassing and speciation of CHONS volatiles, setting the background secondary atmospheric composition during extended photoevaporation at highly irradiated conditions. Using simulations of the coupled atmosphere-interior evolution of irradiated super-Earths, we illustrate that reduced mantles close to the iron-wustite buffer initially produce CO-dominated atmospheres. Hydrodynamic escape continuously removes volatiles while outgassing from the melt replenishes the atmosphere with H2, converted from H2O dissolved in the underlying magma ocean. This leads to a late-stage transition from C- to H-dominated gas that transiently re-inflates super-Earth atmospheres and decreases their bulk densities by up to $\sim$60$\%$ between several hundreds of Myr to Gyr after their formation, prior to complete atmospheric erosion by photoevaporation. In contrast, oxidised mantles, closer to Earth-like geochemistry, strongly buffer their atmospheric composition while exposed to hydrodynamic escape, producing monotonic radius deflation. Reflation events are triggered by geochemically-reduced mantles, intermediate escape efficiencies, high irradiation, and initial water inventories $\gtrsim$ 5 Earth oceans. This redox-dependent evolutionary divergence hinges on the sensitive feedback between interior and atmospheric evolution serving as a potential tracer of historical geochemical state. Population-level reflation signatures of close-in super-Earths may thus serve as tracers of interior geochemistry and formation conditions.
