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Main Authors: Winning, S., Lietzow-Sinjen, M., Wolf, S.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2405.12727
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author Winning, S.
Lietzow-Sinjen, M.
Wolf, S.
author_facet Winning, S.
Lietzow-Sinjen, M.
Wolf, S.
contents Context. As a new growing field, exocartography aims to map the surface features of exoplanets that are beyond the resolution of traditional observing techniques. While photometric approaches have been discussed extensively, polarimetry has received less attention despite its promising prospects. Aims. We demonstrate that the limb polarization of an exoplanetary atmosphere offers valuable insights into its cloud cover distribution. Specifically, we determine an upper limit for the polarimetric precision, which is required to extract information about the latitudinal cloud cover of temperate Jovian planets for scenarios of observations with and without host stars. Methods. To compute the scattered stellar radiation of an exoplanetary atmosphere and to study the polarization at various planetary phase angles, we used the three-dimensional Monte Carlo radiative transfer code POLARIS. Results. When the planetary signal can be measured separately from the stellar radiation, information about the latitudinal cloud cover for polar cap models is accessible at polarimetric sensitivities of $0.1$ %. In contrast, a precision of about $10^{-3}$ ppm is required when the stellar flux is included to gain this information.
format Preprint
id arxiv_https___arxiv_org_abs_2405_12727
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Feasibility study on retrieving exoplanetary cloud cover distributions using polarimetry
Winning, S.
Lietzow-Sinjen, M.
Wolf, S.
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Context. As a new growing field, exocartography aims to map the surface features of exoplanets that are beyond the resolution of traditional observing techniques. While photometric approaches have been discussed extensively, polarimetry has received less attention despite its promising prospects. Aims. We demonstrate that the limb polarization of an exoplanetary atmosphere offers valuable insights into its cloud cover distribution. Specifically, we determine an upper limit for the polarimetric precision, which is required to extract information about the latitudinal cloud cover of temperate Jovian planets for scenarios of observations with and without host stars. Methods. To compute the scattered stellar radiation of an exoplanetary atmosphere and to study the polarization at various planetary phase angles, we used the three-dimensional Monte Carlo radiative transfer code POLARIS. Results. When the planetary signal can be measured separately from the stellar radiation, information about the latitudinal cloud cover for polar cap models is accessible at polarimetric sensitivities of $0.1$ %. In contrast, a precision of about $10^{-3}$ ppm is required when the stellar flux is included to gain this information.
title Feasibility study on retrieving exoplanetary cloud cover distributions using polarimetry
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2405.12727