论文标题
平流层云不会阻碍具有类似地球气氛的系外行星的JWST Transit光谱
Stratospheric Clouds Do Not Impede JWST Transit Spectroscopy for Exoplanets with Earth-Like Atmospheres
论文作者
论文摘要
詹姆斯·韦伯（James Webb）太空望远镜（JWST）将为调查潜在可居住行星的气氛提供机会。气溶胶，在过境光谱中显着静音分子特征，因为它们防止光探测大气的更深层。地球偶尔在15-20公里处具有平流层/高对流层云，这可能会大大限制基础大气的可观察到的深度。我们使用地球大气的太阳掩星来创建绕线矮星星的地球类似物的合成JWST Transit光谱。与以前的调查不同，我们考虑了Scisat卫星的清晰和多云的视线。我们发现，在2.28微米的透明和全球大气之间，大气中有效厚度的最大差异为8.5 km，分辨率为0.02微米。在结合了折射和Pandexo的噪声建模的影响之后，我们发现，如果在Trappist-1系统中存在EXO-ETORTH，JWST将无法检测到像平流层云这样的地球，因为云光谱与清晰光谱的差异最大为10 ppm。对于多云的trappist-1行星进行光谱检索时，TAUREX也无法强烈检测到这些平流层云。但是，如果一个地球大小的行星在白矮人的宜居区中绕轨道，那么我们预计JWST的NIRSPEC将能够在仅4次转移后检测其平流层云。我们得出的结论是，平流层云不会阻碍JWST Transit Spectroscopicy或用于地球样气氛的生物签名的检测。
The James Webb Space Telescope (JWST) will provide an opportunity to investigate the atmospheres of potentially habitable planets. Aerosols, significantly mute molecular features in transit spectra because they prevent light from probing the deeper layers of the atmosphere. Earth occasionally has stratospheric/high tropospheric clouds at 15-20 km that could substantially limit the observable depth of the underlying atmosphere. We use solar occultations of Earth's atmosphere to create synthetic JWST transit spectra of Earth analogs orbiting dwarf stars. Unlike previous investigations, we consider both clear and cloudy sightlines from the SCISAT satellite. We find that the maximum difference in effective thickness of the atmosphere between a clear and globally cloudy atmosphere is 8.5 km at 2.28 microns with a resolution of 0.02 microns. After incorporating the effects of refraction and Pandexo's noise modeling, we find that JWST would not be able to detect Earth like stratospheric clouds if an exo-Earth was present in the TRAPPIST-1 system, as the cloud spectrum differs from the clear spectrum by a maximum of 10 ppm. These stratospheric clouds are also not robustly detected by TauREx when performing spectral retrieval for a cloudy TRAPPIST-1 planet. However, if an Earth size planet were to orbit in a white dwarf's habitable zone, then, we predict that JWST's NIRSpec would be able to detect its stratospheric clouds after only 4 transits. We conclude that stratospheric clouds would not impede JWST transit spectroscopy or the detection of biosignatures for Earth-like atmospheres.
