标题： 潜在可居住行星的特征：从发射光谱中检索大气和行星属性 显示英文标题

标题： Characterization of potentially habitable planets: Retrieval of atmospheric and planetary properties from emission spectra

摘要： 越来越多的潜在可居住的类地行星和行星候选者被持续的行星搜索计划发现。 未来可能通过大气特征的搜索来确定行星的可居住性和生命的存在。 我们想要量化通过红外发射光谱学可能获得的大气参数的准确性。 我们使用了假设的可居住行星的合成观测数据，这些数据是用参数化的大气模型、高分辨率辐射传输模型和简化的噪声模型构建的。 经典统计工具如卡方统计量和最小二乘拟合被用来分析模拟观测数据。 当采用目前计划或提议的系外行星特征任务的设计时，我们发现发射光谱学可能只能提供对类地行星地表条件的弱限制，从而推断其潜在的可居住性。 然而，这些任务设计不太可能允许对可居住行星的大气成分进行表征，即使检测到了CO2。 相比当前任务设计，通过增加信噪比约2-5倍（取决于光谱分辨率），CO2含量可以被表征到两个数量级以内。 O3生物标志物的检测仍然很微弱。 大气温度结构无法被约束。 因此，仅使用二次掩食或目标观测期间的发射光谱学，这样的任务似乎无法实现完整的大气表征。 其他方法如透射光谱学或轨道测光可能需要用来提供额外的约束并打破歧义。 （摘要） 显示英文摘要

摘要： An increasing number of potentially habitable terrestrial planets and planet candidates are found by ongoing planet search programs. The search for atmospheric signatures to establish planetary habitability and the presence of life might be possible in the future. We want to quantify the accuracy of retrieved atmospheric parameters which might be obtained from infrared emission spectroscopy. We use synthetic observations of hypothetical habitable planets, constructed with a parametrized atmosphere model, a high-resolution radiative transfer model and a simplified noise model. Classic statistical tools such as chi2 statistics and least-square fits were used to analyze the simulated observations. When adopting the design of currently planned or proposed exoplanet characterization missions, we find that emission spectroscopy could provide weak limits on surface conditions of terrestrial planets, hence their potential habitability. However, these mission designs are unlikely to allow to characterize the composition of the atmosphere of a habitable planet, even though CO2 is detected. Upon increasing the signal-to-noise ratios by about a factor of 2-5 (depending on spectral resolution) compared to current mission designs, the CO2 content could be characterized to within two orders of magnitude. The detection of the O3 biosignature remains marginal. The atmospheric temperature structure could not be constrained. Therefore, a full atmospheric characterization seems to be beyond the capabilities of such missions when using only emission spectroscopy during secondary eclipse or target visits. Other methods such as transmission spectroscopy or orbital photometry are probably needed in order to give additional constraints and break degeneracies. (abridged)