A grid of polarization models for Rayleigh scattering planetary atmospheres

TL;DR

This paper presents a comprehensive grid of Monte Carlo simulations modeling the intensity and polarization of light reflected by planetary atmospheres with Rayleigh scattering, aiding the interpretation of polarimetric observations of planets.

Contribution

It introduces a large, versatile grid of polarization models for Rayleigh atmospheres, including various scattering properties and layered structures, to interpret planetary polarimetric data.

Findings

Provides quantitative tools for analyzing polarimetric data

Highlights the importance of polarization in characterizing atmospheres

Offers insights into scattering properties and atmospheric stratification

Abstract

We investigate the intensity and polarization of reflected light from planetary atmospheres. We present a large grid of Monte Carlo simulations for planets with Rayleigh scattering atmospheres. We discuss the disk-integrated polarization for phase angles typical of extrasolar planet observations and for the limb polarization effect observable for solar system objects near opposition. The main parameters investigated are single scattering albedo, optical depth of the scattering layer, and albedo of an underlying Lambert surface for a homogeneous Rayleigh scattering atmosphere. We also investigate atmospheres with isotropic scattering and forward scattering aerosol particles, as well as models with two scattering layers. The model grid provides a tool for extracting quantitative results from polarimetric measurements of planetary atmospheres from solar system planets and extrasolar planets, in particular on the scattering properties and stratification of particles in the highest atmosphere layers. Spectropolarimetry of solar system planets offers complementary information to spectroscopy and polarization flux colors can be used for a first characterization of exoplanet atmospheres. From limb polarization measurements, one can set constraints on the polarization at large phase angles.