论文标题
对超球星大气中选定的云成分的极化研究
Polarimetric investigation of selected cloud compositions in exoplanetary atmospheres
论文作者
论文摘要
我们研究了选定的云冷凝物在系外球场大气中对散射恒星辐射极化的影响。我们认为选择了25种云冷凝物，预计将存在于极性的行星大气中。使用三维蒙特卡洛辐射传递代码北极星并假设MIE散射理论，我们计算并研究了散射辐射的净极化，这是光学上的行星相角的函数，在光学到近红外波长时。除了极化状态的众所周知的特征（例如由折射率的实际部分所确定的彩虹）外，折射率的基础假想部分的行为会导致极化程度的增加或下降，并且在特征波长处极化的符号变化。与Al $ _2 $ o $ _3 $和MGFESIO $ _4 $相反，由SIO，MNS，Na $ _2 $ S或ZNS组成的云，在超级行星氛围的上下文中，随着波长的增加而迅速降低了极化程度。此外，根据特定的云冷凝物，极化的符号在约0.5 $ $ m至0.6 $μm的波长下变化。所得的净极化主要是对折射率大的云成分（例如Fe，FES和FEO）的云组成阳性。另外，对于Fe和FES云，长波长的最大极化程度转移到更大的相角，而不是FEO。我们发现，由于它们独特的波长依赖性复合折射率，这些云冷凝水大多数都可以彼此区分。特别是，在特定波长下净极化的净极化的增加或减小是表征超球星大气中云成分的重要特征。
We investigated the impact of selected cloud condensates in exoplanetary atmospheres on the polarization of scattered stellar radiation. We considered a selection of 25 cloud condensates that are expected to be present in extrasolar planetary atmospheres. Using the three-dimensional Monte Carlo radiative transfer code POLARIS and assuming Mie scattering theory, we calculated and studied the net polarization of scattered radiation as a function of planetary phase angle at optical to near-infrared wavelengths. In addition to the well-known characteristics in the state of polarization, such as the rainbow determined by the real part of the refractive index, the behavior of the underlying imaginary part of the refractive index causes an increase or decrease in the degree of polarization and a change of sign in the polarization at a characteristic wavelength. In contrast to Al$_2$O$_3$ and MgFeSiO$_4$, clouds composed of SiO, MnS, Na$_2$S, or ZnS produce a rapidly decreasing degree of polarization with increasing wavelength in the context of an exoplanetary atmosphere. Furthermore, the sign of the polarization changes at a wavelength of about 0.5 $μ$m to 0.6 $μ$m, depending on the specific cloud condensate. The resulting net polarization is mainly positive for cloud compositions with large imaginary parts of the refractive index, such as Fe, FeS, and FeO. In addition, for Fe and FeS clouds, the maximum degree of polarization at long wavelengths is shifted to larger phase angles than for FeO. We found that most of these cloud condensates are distinguishable from each other due to their unique wavelength-dependent complex refractive index. In particular, an increase or decrease of the net polarization as a function of wavelength and a change of sign in the polarization at specific wavelengths are important features for characterizing cloud compositions in exoplanetary atmospheres.
