Geometric effects on the flux and polarization signals of Jupiter-like exoplanets

Geometric effects on the flux and polarization signals of Jupiter-like exoplanets

Palmer, Chris (TU Delft Aerospace Engineering)

Stam, Daphne (mentor)

Delft University of Technology

Aerospace Engineering

2019-10-09

Polarimetry has already played an important role in the characterization of planets within the solar system and is expected to prove useful in the detection and characterization of exoplanets. The reflected flux and polarization signals contain information about the microphysical properties of an atmosphere but are influenced by the geometry of the system. For this study, I adapted a radiative transfer code and used it to compare the influence of inhomogeneous cloud cover, rotation-induced oblateness, orbit inclination, tidal deformation and obliquity on the disk-integrated reflected light signal, for visible light with wavelength 0.7 microns. I have also investigated the importance of including a spatially resolved stellar disk in the model planet's sky when simulating scattering by exoplanetary atmospheres. It was found that a degree of polarization of the order of 1% can arise from rotational-induced oblateness in reflected light, and that a planet's shape may be derived from the normalized flux signal without knowledge of the percentage of cloud cover in some cases. Giving the host star a non-negligible angular size makes a significant difference to the light signal when the planet is in a close-in orbit (D<0.05 AU). Proximity to a spatially extended star leads to a washing out of optical features such as the glory, as well as producing a non-zero reflected flux during transit.

http://resolver.tudelft.nl/uuid:8b6e394a-8d4a-4c98-bdbf-06ff37524806

Student theses

master thesis

© 2019 Chris Palmer