Polarization in exoplanetary systems caused by transits, grazing transits, and starspots

TL;DR

This paper uses numerical simulations to study how transits, grazing transits, and starspots affect flux and polarization signals in exoplanet systems, aiding in orbital and stellar surface characterization.

Contribution

It introduces a method to analyze polarization variations caused by transits and starspots, enhancing the understanding of exoplanetary system geometries.

Findings

Transit polarization effects are detectable in certain systems.

Polarization can help distinguish grazing from near-grazing planets.

Starspots influence polarization and can reveal spot properties.

Abstract

We present results of numerical simulations of flux and linear polarization variations in transiting exoplanetary systems, caused by the host star disk symmetry breaking. We consider different configurations of planetary transits depending on orbital parameters. Starspot contribution to the polarized signal is also estimated. Applying the method to known systems and simulating observational conditions, a number of targets is selected where transit polarization effects could be detected. We investigate several principal benefits of the transit polarimetry, particularly, for determining orbital spatial orientation and distinguishing between grazing and near-grazing planets. Simulations show that polarization parameters are also sensitive to starspots, and they can be used to determine spot positions and sizes.