标题： 基于贝叶斯的系外地球远程生物特征识别（BARBIE）I：在日冕观测模拟中使用基于网格的嵌套抽样进行H₂O探测 显示英文标题

标题： Bayesian Analysis for Remote Biosignature Identification on exoEarths (BARBIE) I: Using Grid-Based Nested Sampling in Coronagraphy Observation Simulations for H2O

摘要： 检测系外行星大气中的水（H₂O）是确定行星宜居性的第一步。 目前，日冕仪设计限制了用于检测H₂O的观测策略，要求选择特定的波段以优化丰度约束。 为了研究使用基于日冕仪的直接成像技术初步表征宜居行星的最佳观测策略，我们量化了作为信噪比（SNR）和分子丰度函数的H₂O可探测性，覆盖可见光波段（0.5-1微米）中的25个波段。 我们使用一个预先构建的网格，该网格由一系列丰度和压力范围内的140万几何反照率光谱组成，并通过插值生成用于高效嵌套采样过程的前向模型PSGnest。 我们首先测试类似现代地球的双胞胎大气中H₂O的可探测性，然后扩展到更广泛的H₂O丰度范围；对于每个丰度值，我们根据数据的有效信噪比（SNR）约束最优的20%波段。 我们展示了H₂O可探测性作为信噪比、波长和丰度函数的结果，并讨论如何利用这些结果优化未来的日冕仪仪器设计。 我们发现，在某些波长处，对于接近地球历史最高值的丰度，使用中等信噪比的数据可以在0.74微米处检测到H₂O；而在0.9微米处，使用低信噪比数据可以检测到现代地球的H₂O丰度。 显示英文摘要

摘要： Detecting H2O in exoplanet atmospheres is the first step on the path to determining planet habitability. Coronagraphic design currently limits the observing strategy used to detect H2O, requiring the choice of specific bandpasses to optimize abundance constraints. In order to examing the optimal observing strategy for initial characterization of habitable planets using coronagraph-based direct imaging, we quantify the detectability of H2O as a function of signal-to-noise ratio (SNR) and molecular abundance across 25 bandpasses in the visible wavelength range (0.5-1 micron). We use a pre-constructed grid consisting of 1.4 million geometric albedo spectra across a range of abundance and pressure, and interpolate the produce forward models for an efficient nested sampling routine, PSGnest. We first test the detectability of H2O in atmospheres that mimix a modern-Earth twin, and then expand to examine a wider range of H2O abundances; for each abundance value, we constrain the optimal 20% bandpasses based on the effective signal-to-noise ratio (SNR) of the data. We present our findings of H2O detectability as functions of SNR, wavelength, and abundance, and discuss how to use these results for optimizing future coronographic instrument design. We find that there are specific points in wavelength where H2o can be detected down to 0.74 micron with moderate-SNR data for abundances at the upper end of Earth's presumed historical values, while at 0.9 micron, detectability is possible with low-SNR data at modern Earth abundances of H2O.