Formation of Silicate and Titanium Clouds on Hot Jupiters
Formation of Silicate and Titanium Clouds on Hot Jupiters
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热木星上硅酸盐和钛云的形成
DOI：
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发表时间：
2018
影响因子：
4.9
通讯作者：
V. Parmentier
中科院分区：
文献类型：
--
作者：
D. Powell;Xi Zhang;P. Gao;V. Parmentier
我们首次提出了一个面元方案微物理和垂直输运模型来确定热木星大气中钛和硅酸盐云粒子的尺寸分布。我们根据第一性原理对赤道四个典型经度上的行星网格的粒子尺寸分布进行了预测，并研究了观测到的云特性如何依赖于大气热结构和垂直混合。预测的大小分布经常是双峰的，形状不规则。总云量与平衡温度呈负相关，与大气混合呈正相关。东西两翼的云特征有明显的差异，且随平衡温度的升高而增大。除了中红外波段的特征外，云的不透明度在广泛的波长范围内基本保持不变。在相同的波长范围内，前向散射也很重要。使用完全分辨的云粒大小分布，而不是平均粒子大小，对所产生的云层不透明度有明显的影响。对云不透明度贡献最大的粒子大小强烈依赖于云的粒子大小分布。我们预测，硅酸盐或钛云不太可能是许多热木星中出现的光学瑞利散射斜率的原因。我们认为，发射中的云不透明可以通过深部大气中是否存在冷陷阱来灵敏地追踪行星深部内部的热状态。
We present the first application of a bin-scheme microphysical and vertical transport model to determine the size distribution of titanium and silicate cloud particles in the atmospheres of hot Jupiters. We predict particle size distributions from first principles for a grid of planets at four representative equatorial longitudes, and investigate how observed cloud properties depend on the atmospheric thermal structure and vertical mixing. The predicted size distributions are frequently bimodal and irregular in shape. There is a negative correlation between the total cloud mass and equilibrium temperature as well as a positive correlation between the total cloud mass and atmospheric mixing. The cloud properties on the east and west limbs show distinct differences that increase with increasing equilibrium temperature. Cloud opacities are roughly constant across a broad wavelength range, with the exception of features in the mid-infrared. Forward-scattering is found to be important across the same wavelength range. Using the fully resolved size distribution of cloud particles as opposed to a mean particle size has a distinct impact on the resultant cloud opacities. The particle size that contributes the most to the cloud opacity depends strongly on the cloud particle size distribution. We predict that it is unlikely that silicate or titanium clouds are responsible for the optical Rayleigh scattering slope seen in many hot Jupiters. We suggest that cloud opacities in emission may serve as sensitive tracers of the thermal state of a planet’s deep interior through the existence or lack of a cold trap in the deep atmosphere.
通过等离子体沉积和等离子体溅射在亚恒星大气中演化尘埃云
影响因子：
6.5
作者：
Stark C
通讯作者：
Stark C