论文标题
小型系外行星的反射光谱II：陆生系外星的表征
Reflected spectroscopy of small exoplanets II: characterization of terrestrial exoplanets
论文作者
论文摘要
能够进行高对比度成像的太空望远镜被认为是在附近的阳光恒星周围寻找陆地行星的途径，并表征了它们的潜在宜居性。因此，必须量化通过直接成像的地面系外行星获得的反射光谱的能力，以及现有的工作着重于现代地球的行星类似物。在这里，我们超越了地球类似物，并使用贝叶斯检索算法，Exorel $^\ re $，以确定我们可以从反射的光谱中学到的陆地系外行星。认识到陆地系外行星的潜在多样性，我们的重点是区分大气场景，而没有任何对主要气体的知识。我们发现，尽管光条中的中等分辨率频谱（$ 0.4-1.0 \μ$ m）可能充分表征了现代地球模拟，但可能会导致类似于Archean Earth或具有Co $ _2 $ _2 $ dominations Amberiation的行星的解释。包括在近红外频段中的观察（$ 1.0-1.8 \μ$ m）可以防止此错误，确定主组件（n $ _2 $，o $ _2 $或CO $ _2 $），并量化微量的气体（h $ _2 $ o，o $ $ _3 $，以及CH $ _4 $）。这些结果可用于定义科学要求和设计将来系外行星直接成像任务的波长带宽和观察计划。
A space telescope capable of high-contrast imaging has been recognized as the avenue toward finding terrestrial planets around nearby Sun-like stars and characterizing their potential habitability. It is thus essential to quantify the capability of reflected light spectroscopy obtained through direct imaging for terrestrial exoplanets, and existing work focused on planetary analogs of modern Earth. Here we go beyond Earth analogs and use a Bayesian retrieval algorithm, ExoReL$^\Re$, to determine what we could learn about terrestrial exoplanets from their reflected light spectra. Recognizing the potential diversity of terrestrial exoplanets, our focus is to distinguish atmospheric scenarios without any a priori knowledge of the dominant gas. We find that, while a moderate-resolution spectrum in the optical band ($0.4-1.0\ μ$m) may sufficiently characterize a modern Earth analog, it would likely result in incorrect interpretation for planets similar to Archean Earth or having CO$_2$-dominated atmospheres. Including observations in the near-infrared bands ($1.0-1.8\ μ$m) can prevent this error, determine the main component (N$_2$, O$_2$, or CO$_2$), and quantify trace gases (H$_2$O, O$_3$, and CH$_4$) of the atmosphere. These results are useful to define the science requirements and design the wavelength bandwidth and observation plans of exoplanet direct imaging missions in the future.
