Spectral slopes in optical transmission spectra of exoplanetary atmospheres encapsulate information on the properties of exotic clouds. The slope is usually attributed to the Rayleigh scattering caused by tiny aerosol particles, whereas recent retrieval studies have suggested that the slopes are often steeper than the canonical Rayleigh slopes. Here, we propose that photochemical haze formed in vigorously mixing atmospheres can explain such super-Rayleigh slopes. We first analytically show that the spectral slope can be steepened by the vertical opacity gradient in which atmospheric opacity increases with altitude. Using a microphysical model, we demonstrate that such an opacity gradient can be naturally generated by photochemical haze, especially when the eddy mixing is substantially efficient. The transmission spectra of hazy atmospheres can be demarcated into four typical regimes in terms of the haze mass flux and eddy diffusion coefficient. We find that the transmission spec...

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光化学霾产生的系外行星透射光谱中的超瑞利斜率

系外大气的光学透射光谱中的光谱斜率封装了有关外来云的性质的信息。该斜率通常归因于微小的气溶胶颗粒引起的瑞利散射，而最近的检索研究表明，该斜率通常比规范的瑞利斜率更陡。在这里，我们提出在剧烈混合的气氛中形成的光化学雾度可以解释这种超瑞利斜率。我们首先分析性地表明，可以通过垂直不透明度梯度使光谱斜率变陡，其中大气不透明度随高度增加。使用微物理模型，我们证明了这种不透明度梯度可以通过光化学雾自然生成，尤其是在涡流混合非常有效的情况下。根据雾度质量通量和涡流扩散系数，朦胧气氛的透射光谱可以划分为四个典型的区域。我们发现传动规格...