论文标题
M矮人陆生外行星的海洋损失的高分辨率光谱歧视因素
High-Resolution Spectral Discriminants of Ocean Loss for M Dwarf Terrestrial Exoplanets
论文作者
论文摘要
在不久的将来，极大的地面望远镜可能会进行太阳系以外的一些生命搜索。可以使用来自附近系外行星大气的反射光的高光谱分辨率观察来寻找生物签名氧。但是，尽管地球丰富的O $ _2 $是光合作用的，但通过水蒸气光解和随后的氢逃生，早期海洋损失也可能产生高大气o $ _2 $。为了探索如何使用光谱区分这两个氧气来源，我们生成了类似可居住的地球的高分辨率逐线合成光谱，并产生了居住的地球状后代的阵容，并产生了近代的阵阵阵阵centima centauri b。我们从0.63到1.27 $μ$ m的四个频段O $ _2 $的强度和轮廓，并量化它们的相对可检测性。我们发现10个bar o $ _2 $后垂直散失的气氛对氧气带，尤其是1.27 $μ$ m频段有很大的抑制作用。这种抑制是由于这些更庞大的O $ _2 $大气中产生的额外的强，广泛的O $ _2 $ -O $ _2 $碰撞引起的吸收（CIA），这对于光合作用产生的较小的氧气并不存在。因此，对1.27 $μ$ m的任何检测在反射光中的频段都表明较低的地球o $ _2 $级别，这表明可能是光合起源的。但是，0.69 $ $ m o $ _2 $频段相对不受o $ _2 $ -o -o $ $ _2 $ cia的影响，并且可以通过发现强劲的0.69 $ $ M o $ $ $ $ $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ $ _2 $ band和未固定的1.27 $ $ m $ m $ m $ m $ m $ $ m $ _2 $ cia的存在。这些结果为观察和解释外部活动的o $ _2 $提供了一种策略，这可以由未来的基于地面的望远镜来考虑。
In the near future, extremely-large ground-based telescopes may conduct some of the first searches for life beyond the solar system. High-spectral resolution observations of reflected light from nearby exoplanetary atmospheres could be used to search for the biosignature oxygen. However, while Earth's abundant O$_2$is photosynthetic, early ocean loss may also produce high atmospheric O$_2$ via water vapor photolysis and subsequent hydrogen escape. To explore how to use spectra to discriminate between these two oxygen sources, we generate high-resolution line-by-line synthetic spectra of both a habitable Earth-like, and post-ocean-loss Proxima Centauri b. We examine the strength and profile of four bands of O$_2$ from 0.63 to 1.27 $μ$m, and quantify their relative detectability. We find that 10 bar O$_2$ post-ocean-loss atmospheres have strong suppression of oxygen bands, and especially the 1.27$μ$m band. This suppression is due to additional strong, broad O$_2$-O$_2$ collisionally-induced absorption (CIA) generated in these more massive O$_2$atmospheres, which is not present for the smaller amounts of oxygen generated by photosynthesis. Consequently, any detection of the 1.27$μ$m band in reflected light indicates lower Earth-like O$_2$ levels, which suggests a likely photosynthetic origin. However, the 0.69 $μ$m O$_2$ band is relatively unaffected by O$_2$-O$_2$ CIA, and the presence of an ocean-loss high-O$_2$ atmosphere could be inferred via detection of a strong 0.69 $μ$m O$_2$ band, and a weaker or undetected 1.27 $μ$m band. These results provide a strategy for observing and interpreting O$_2$ in exoplanet atmospheres, that could be considered by future ground-based telescopes.
