Ultraviolet Spectropolarimetry as a Tool for Understanding the Diversity of Exoplanetary Atmospheres

TL;DR

Ultraviolet spectropolarimetry offers a powerful method to analyze exoplanetary atmospheres by revealing aerosol properties and cloud patterns, independent of orbital geometry, especially with advanced space-based instruments.

Contribution

This paper proposes using high-resolution ultraviolet spectropolarimetry with space telescopes to study exoplanet atmospheres in unprecedented detail.

Findings

Polarization reveals aerosol coverage, particle size, and cloud patterns.

Spectropolarimetry can probe atmospheres independently of orbital geometry.

Potential for detailed atmospheric characterization with future space telescopes.

Abstract

The polarization state of starlight reflected by a planetary atmosphere uniquely reveals coverage, particle size, and composition of aerosols as well as changing cloud patterns. It is not possible to obtain a comparable level of detailed from flux-only observations. Furthermore, polarization observations can probe the atmosphere of planets independently of the orbital geometry (i.e., transiting and non-transiting planets). We show that a high-resolution spectropolarimeter with a broad wavelength coverage, particularly if attached to a large space telescope, would enable simultaneous study of the polarimetric exoplanet properties of the continuum and to look for and characterize the polarimetric signal due to scattering from single molecules.