发表机构
University of Texas at Austin; Center for Planetary Systems Habitability, The University of Texas at Austin; Institute for Geophysics, The University of Texas at Austin; Department of Earth and Planetary Sciences, Jackson School of Geosciences, The University of Texas at Austin（德克萨斯大学奥斯汀分校; 德克萨斯大学奥斯汀行星系统宜居性中心; 德克萨斯大学地球物理研究所; 德克萨斯大学杰克逊地球科学学院地球与行星科学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过微物理云模型Nimbus模拟，发现行星际尘埃粒子烧蚀可增加系外行星云粒子数密度并增强硅酸盐光谱特征，尤其对冷行星影响显著，并能解释WASP-107 b的观测现象。
AI 中文摘要
行星际尘埃粒子（IDPs）遍布整个太阳系，地球每天经历约100吨IDPs的质量通量。这些粒子在上层大气中烧蚀，输送形成夜光云和平流层云的气溶胶。由于IDPs以系外黄道尘埃盘（exozodis）的形式存在于系外行星系统中，系外行星很可能也经历持续的IDPs下落。在本工作中，我们研究了IDPs对气态巨行星和褐矮星云结构的影响，并确定其可观测性。我们将微物理云模型Nimbus应用于Sonora Diamondback模型网格，以覆盖广泛的有效温度、表面重力、大气混合常数和IDP质量通量。我们的结果表明，IDP下落增加了云粒子数密度，减小了云粒子半径，并增强了透射和热发射光谱中的硅酸盐特征。具有较低大气混合速率、有效温度和重力的系外行星对IDPs更为敏感。最值得注意的是，它们导致在较冷行星中出现可观测的硅酸盐吸收特征，而在这些行星中硅酸盐云原本是不可观测的。WASP-107 b就是这样一个具有硅酸盐粒子观测证据的系外行星的例子。使用Nimbus，我们发现，100倍地球类似IDP质量通量，具有太阳系类似IDP成分（石英（SiO2）、顽火辉石（MgSiO3）和铁（Fe）），可以解释WASP-107 b中高空硅酸盐粒子的观测结果。
英文摘要
Interplanetary dust particles (IDPs) are present throughout the Solar System, with Earth experiencing a mass flux of roughly 100 tonnes of IDPs per day. These particles ablate in the upper atmosphere, delivering aerosols that form noctilucent and stratospheric clouds. Since IDPs are present in exoplanet systems as exozodiacal dust disks (exozodis), it is likely that exoplanets experience a constant infall of IDPs as well. In this work, we investigate the effect of IDPs on the cloud structure of gas-giant exoplanets and brown dwarfs, and determine their observability. We apply the microphysical cloud model Nimbus to the Sonora Diamondback model grid to cover a wide range of effective temperatures, surface gravities, atmospheric mixing constants, and IDP mass fluxes. Our results show that IDP infall increases cloud particle number densities, decreases cloud particle radii, and enhances silicate features in transmission and thermal emission spectra. Exoplanets with lower atmospheric mixing rates, effective temperatures, and gravity are more sensitive to IDPs. Most notably, they lead to observable silicate absorption features in colder planets where silicate clouds would otherwise not be observable. WASP-107 b is an example of such an exoplanet with observational evidence of silicate particles. Using Nimbus, we found that a 100 times Earth-like IDP mass flux with a Solar-System-like IDP composition of quartz (SiO2), enstatite (MgSiO3), and iron (Fe) can explain the observations of high altitude silicate particles in WASP-107 b.
Comments18 pages, 8 Figures, accepted for publication in ApJ
