AI 中文总结
本研究评估系外行星大型干涉仪（LIFE）的性能，利用基于ARCiS和LIFEsim的反演框架，通过光谱测量区分类地大小岩质系外行星的氧化态，明确了不同氧化态下的特征示踪分子。
AI 中文摘要
岩质系外行星的氧化态预计会通过影响火山释放气体的化学组成，在塑造其次生大气的化学组成中发挥关键作用。通过直接大气表征区分行星的氧化还原状态，将为深入了解系外行星次生大气的形成与演化提供线索，并为推定生物标志物的背景化学提供信息。系外行星大型干涉仪（LIFE）任务概念旨在采用天基中红外消光干涉仪来表征系外行星大气。本研究评估了LIFE通过直接光谱测量区分岩质系外行星氧化还原状态的性能，重点关注类地大小系外行星次生大气中氧化还原敏感分子的可观测性与光谱特征。我们开发并应用了基于系外行星科学的巧妙建模代码（ARCiS）和LIFE任务模拟器（LIFEsim）的反演框架，模拟了一系列合理地幔氧化还原条件下的类地大小行星大气观测。模拟结果显示，基线配置下的LIFE能够以足够的精度成功约束主要大气物种（如CO₂、CH₄和NH₃），从而区分在10秒差距处绕类太阳恒星运行的行星的氧化态。反演得到的氧化还原敏感分子在不同氧化态间呈现明显趋势：氧化环境（氧逸度fO₂~IW+2至IW+6，其中IW为铁-方铁矿缓冲剂）中CO₂占主导，还原环境（fO₂~IW-2至IW-6）中NH₃占主导，CH₄则作为中间氧化态（fO₂~IW+4至IW-4）间的强示踪剂。
英文摘要
The oxidation state of rocky exoplanets is expected to play a fundamental role in shaping the chemical composition of their secondary atmospheres by influencing the chemical composition of volcanically released gasses. Distinguishing planetary redox states through direct atmospheric characterization would offer insight into the formation and evolution of secondary atmospheres on exoplanets and inform the background chemistry of putative biosignatures. The Large Interferometer For Exoplanets (LIFE) mission concept aims to employ a space-based mid-infrared nulling interferometer to characterize exoplanetary atmospheres. In this work, we assess LIFE's performance in distinguishing the redox states of rocky exoplanets by direct spectroscopic measurements. We focus on the observability and spectral features of redox-sensitive molecules in secondary atmospheres of Earth-sized exoplanets. We develop and apply a retrieval framework based on the ARtful modeling Code for exoplanet Science (ARCiS) and the LIFE mission simulator (LIFEsim) to simulate observations of Earth-sized planets with atmospheres from a range of plausible mantle redox conditions. Our simulations show that LIFE in its baseline configuration can successfully constrain dominant atmospheric species (e.g. CO2, CH4 and NH3) with sufficient accuracy to distinguish redox states for planets orbiting a Sun-like star at 10 pc. Retrieved redox-sensitive molecules show clear trends across oxidation states, with CO2 dominating in oxidizing (with oxygen fugacity fO2 $\sim$ IW+2 to IW+6, where IW is the iron-w$ü$stite buffer) environments and NH3 in reducing (fO2 $\sim$ IW-2 to IW-6) environments, and CH4 serving as a strong tracer among intermediate (fO2 $\sim$ IW+4 to IW-4) oxidation states.
Comments13 pages, 7 figures, accepted for publication at Monthly Notices of the Royal Astronomical Society (MNRAS)
Journal refMNRAS 552, 1 (2026)
