发表机构
University of California, Riverside; NASA Goddard Space Flight Center; Jet Propulsion Laboratory, California Institute of Technology; Johns Hopkins University Applied Physics Laboratory（加州大学河滨分校; 美国宇航局戈达德太空飞行中心; 加州理工学院喷气推进实验室; 约翰斯·霍普金斯大学应用物理实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出利用即将开展的DAVINCI任务获取的金星高保真大气剖面数据，解决类地系外行星光谱的简并性问题，可大幅提升系外行星大气建模的精度。
AI 中文摘要
通过透射光谱和发射光谱对拥有以二氧化碳为主的浓厚大气层的类地系外行星进行表征时，会受到大气成分、云结构与表面条件之间简并性的限制。这种简并性在金星带内或附近的行星上尤为显著，在这类行星上，硫酸气溶胶层和深层大气的不透明度使得许多光学/红外波长无法探测到低层大气和表面。金星是这类行星中唯一可探测的类比天体，但目前对其完整大气剖面的认知依赖于数十年前的原位数据，而这些数据存在已知局限性。本文证明，即将开展的DAVINCI（深层大气金星惰性气体、化学与成像探测）任务将提供全面、高保真的大气剖面数据，这些数据是解决诸多此类简并性问题所必需的。我们量化了大气剖面不确定性如何转化为以二氧化碳为主的类地行星的模拟透射光谱和热发射光谱的不确定性，结果显示，在DAVINCI任务后，由当前大气剖面不确定性导致的金星基准光谱的模拟 spread（分布），透射光谱将减少约4-5倍，热发射光谱将减少约5-15倍，从而为模拟拥有类金星大气的系外行星提供相应改进的基准和先验。我们进一步证明，对于无云大气情况，这些改进幅度更大，因为此时不透明度下限由气相过程而非气溶胶决定，而DAVINCI前的数据在云下区域差异最大。我们的研究强调了金星在JWST和HWO时代对岩质系外行星大气表征的重要性，并证明DAVINCI测量将直接改进系外行星大气建模。
英文摘要
The characterization of terrestrial exoplanets with thick, CO$_2$-dominated atmospheres via transmission and emission spectroscopy is limited by degeneracies between atmospheric composition, cloud structure, and surface conditions. These degeneracies are particularly acute for planets in or near the Venus Zone, where sulfuric acid aerosol layers and deep-atmosphere opacity render the lower atmosphere and surface spectroscopically inaccessible via many optical/IR wavelengths. Venus provides the only accessible analog to such worlds, yet current knowledge of its full atmospheric profile relies on decades-old in situ data with known limitations. Here we demonstrate that the forthcoming DAVINCI (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) mission will provide the comprehensive, high-fidelity atmospheric profile data necessary to resolve many of these degeneracies. We quantify how atmospheric profile uncertainties translate into uncertainties in modeled transmission and thermal emission spectra of CO$_2$-dominated terrestrial worlds, and show that the spread in the modeled Venus benchmark spectrum arising from current atmospheric profile uncertainties will decrease by factors of $\sim$4--5 for transmission and $\sim$5--15$\times$ for thermal emission after DAVINCI, providing a correspondingly improved benchmark and prior for the modeling of exoplanets with Venus-like atmospheres. We further demonstrate that these improvement factors are larger for the cloud-free atmospheric case, where the opacity floor is set by gas-phase processes rather than aerosols, because the pre-DAVINCI data are most discrepant in the sub-cloud region. Our results highlight the importance of Venus for the atmospheric characterization of rocky exoplanets in the JWST and HWO era, and demonstrate how DAVINCI measurements will directly improve exoplanet atmospheric modeling.
Comments17 pages, 4 figures, 2 tables, accepted for publication in the Astronomical Journal
