The precise characterization of terrestrial atmospheres with the James Webb Space Telescope (JWST) is one of the utmost goals of exoplanet astronomy in the next decade. With JWST’s impending launch, it is crucial that we are well prepared to understand the subtleties of terrestrial atmospheres—particularly ones that we may have not needed to consider before due to instrumentation limitations. In this work we show that patchy ice cloud variability is present in the upper atmospheres of M-dwarf terrestrial planets, particularly along the limbs. Here we test whether these variable clouds will introduce unexpected biases in the multi-epoch observations necessary to constrain atmospheric abundances. Using 3D ExoCAM general circulation models of TRAPPIST-1e, we simulate five different climates with varying pCO₂ to explore the strength of this variability. These models are post-processed using NASA Goddard’s Planetary Spectrum Generator and PandExo to generate simulated observations with JWST’s NIRSpec PRISM mode at 365 different temporal outputs from each climate. Assuming the need for 10 transits of TRAPPIST-1e to detect molecular features at great confidence, we then use CHIMERA to retrieve on several randomly selected weighted averages of our simulated observations to explore the effect of multi-epoch observations with variable cloud cover along the limb on retrieved abundances. We find that the variable spectra do not affect retrieved abundances at detectable levels for our sample of TRAPPIST-1e models.

使用詹姆斯韦伯太空望远镜 (JWST) 精确表征地球大气是未来十年系外行星天文学的最大目标之一。随着 JWST 即将发射，我们必须做好充分准备以了解地球大气层的微妙之处——尤其是那些我们之前由于仪器限制可能不需要考虑的大气层。在这项工作中，我们表明，在 M 矮类地球行星的高层大气中，尤其是在四肢附近，存在片状冰云变化。在这里，我们测试这些可变云是否会在限制大气丰度所需的多时代观测中引入意想不到的偏差。使用TRAPPIST-1e 的3D ExoCAM环流模型，我们模拟了具有不同 pCO 的五种不同气候₂探索这种可变性的强度。这些模型使用 NASA Goddard 的行星光谱发生器和PandExo进行后处理，以使用 JWST 的 NIRSpec PRISM 模式在来自每种气候的 365 种不同时间输出下生成模拟观测。假设需要 TRAPPIST-1e 的 10 次过境以极大的信心检测分子特征，然后我们使用CHIMERA检索我们模拟观测的几个随机选择的加权平均值，以探索多历元观测的影响，沿边缘具有可变云量在检索到的丰度上。我们发现，对于我们的 TRAPPIST-1e 模型样本，可变光谱不会影响可检测水平的检索丰度。