Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Super-Rayleigh Slopes in Transmission Spectra of Exoplanets Generated by
  Photochemical Haze   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 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
spectrum can have the spectral slope 2--4 times steeper than the Rayleigh slope
if the eddy diffusion coefficient is sufficiently high and the haze mass flux
falls into a moderate value. Based on the eddy diffusion coefficient suggested
by a recent study of atmospheric circulations, we suggest that photochemical
haze preferentially generates super-Rayleigh slopes at planets with equilibrium
temperature of 1000--1500 K, which might be consistent with results of recent
retrieval studies. Our results would help to interpret the observations of
spectral slopes from the perspective of haze formation.

33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con