标题： 寻找边缘：系外行星反射光谱中红边可探测性的贝叶斯探索 显示英文标题

标题： In Search of the Edge: A Bayesian Exploration of the Detectability of Red Edges in Exoplanet Reflection Spectra

摘要： 反射光谱学在表征潜在宜居的类地系外行星的大气和表面方面具有巨大潜力。现代地球表面在750纳米附近由于植被（红边）引起了一个明显的反照率变化，如果系外行星上存在这种特征，将会留下强烈的光谱信号。然而，从反射光谱中提取波长相关的表面属性的研究相对较少。在此，我们提出了一种新的表面反照率参数化方法，能够检索先验未知的“边缘”特征的波长位置。我们证明了波长相关的表面反照率模型在检索大气组成方面具有更高的准确性。对于模拟的现代地球类比的反射光谱，波长相关的表面也通常优于均匀反照率模型，即使在中等信噪比（S/N = 10）和类似地球云的情况下也是如此。此外，现代地球的红边位置可以被稳健且精确地约束（信噪比为10时误差在70纳米以内）。我们的结果表明，未来的基于空间的直接成像任务有可能推断岩石系外行星的地表组成，包括类似于现代地球上由生命引起的光谱边缘。 显示英文摘要

摘要： Reflection spectroscopy holds great promise for characterizing the atmospheres and surfaces of potentially habitable terrestrial exoplanets. The surface of the modern Earth exhibits a sharp albedo change near 750 nm caused by vegetation - the red edge - which would leave a strong spectral signature if present on an exoplanet. However, the retrieval of wavelength-dependent surface properties from reflection spectra has seen relatively little study. Here, we propose a new surface albedo parameterization capable of retrieving the wavelength location of a priori unknown 'edge-like' features. We demonstrate that a wavelength-dependent surface albedo model achieves higher accuracy in retrieving atmospheric composition. Wavelength-dependent surfaces are also generally preferred over a uniform albedo model when retrieving simulated reflection spectra for a modern Earth analog, even for moderate signal-to-noise ratios (S/N = 10) and Earth-like clouds. Further, the location of the modern Earth's red edge can be robustly and precisely constrained (within 70 nm for S/N = 10). Our results suggest that future space-based direct imaging missions have the potential to infer surface compositions for rocky exoplanets, including spectral edges similar to those caused by life on the modern Earth.