Spectropolarimetry as a tool for understanding the diversity of planetary atmospheres

Loïc Rossi (1) , J. Berzosa-Molina (2) , J.-M. Desert (3) , L. Fossati (4) , A. Garcia-Muñoz (5) , C. Haswell (6) , P. Kabath (7) , K Kislyakova (8) , D. Stam (9) , A. Vidotto (10)

1 PLANETO - LATMOS
2 GMV
3 UvA - University of Amsterdam [Amsterdam] = Universiteit van Amsterdam
4 IWF - Space Research Institute of Austrian Academy of Sciences
5 TU - Technical University of Berlin / Technische Universität Berlin
6 OU - The Open University [Milton Keynes]
7 ASU / CAS - Astronomical Institute of the Czech Academy of Sciences
8 University of Vienna [Vienna]
9 TU Delft - Delft University of Technology
10 Trinity College Dublin

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 detail from flux-only observations. It is therefore a powerful tool to better understand the crucial role played by clouds and aerosols in the chemistry, dynamics, and radiative balance of a planet. Furthermore, polarization observations can probe the atmosphere of planets independently of the orbital geometry (hence it applies to both transiting and non-transiting exoplanets). A high-resolution spectropolarimeter with a broad wavelength coverage, particularly if attached to a large space telescope, would enable simultaneous study of the polarimetric planetary properties of the continuum and to look for and characterize the polarimetric signal due to scattering from single molecules, providing detailed information about the composition and vertical structure of the atmosphere.

Mots clés: Atmospheres; Exoplanets; Polarimetry

Domaines: Planète et Univers [physics]

Loïc Rossi, J. Berzosa-Molina, J.-M. Desert, L. Fossati, A. Garcia-Muñoz, et al.. Spectropolarimetry as a tool for understanding the diversity of planetary atmospheres. Experimental Astronomy, 2022, 54, pp.1187-1196. ⟨10.1007/s10686-021-09813-w⟩. ⟨insu-03480395v2⟩