Reflected-light Phase Curves with PICASO: A Kepler-7b Case Study

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Hauptverfasser: Hamill, Colin D., Johnson, Alexandria V., Batalha, Natasha, Nag, Rowan, Gao, Peter, Adams, Danica, Kataria, Tiffany
Format: Preprint
Veröffentlicht: 2024
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author Hamill, Colin D.
Johnson, Alexandria V.
Batalha, Natasha
Nag, Rowan
Gao, Peter
Adams, Danica
Kataria, Tiffany
author_facet Hamill, Colin D.
Johnson, Alexandria V.
Batalha, Natasha
Nag, Rowan
Gao, Peter
Adams, Danica
Kataria, Tiffany
contents Examining reflected light from exoplanets aids in our understanding of the scattering properties of their atmospheres and will be a primary task of future flagship space- and ground-based telescopes. We introduce an enhanced capability of Planetary Intensity Code for Atmospheric Scattering Observations (PICASO), an open-source radiative transfer model used for exoplanet and brown dwarf atmospheres, to produce reflected light phase curves from three-dimensional atmospheric models. Since PICASO is coupled to the cloud code Virga, we produce phase curves for different cloud condensate species and varying sedimentation efficiencies (fsed) and apply this new functionality to Kepler-7b, a hot Jupiter with phase curve measurements dominated by reflected starlight. We model three different cloud scenarios for Kepler-7b: MgSiO3 clouds only, Mg2SiO4 clouds only, and Mg2SiO4, Al2O3, and TiO2 clouds. All our Virga models reproduce the cloudy region west of the substellar point expected from previous studies, as well as clouds at high latitudes and near the eastern limb, which are primarily composed of magnesium silicates. Al2O3 and TiO2 clouds dominate near the substellar point. We then compare our modeled reflected light phase curves to Kepler observations and find that models with all three cloud condensate species and low sedimentation efficiencies (0.03 - 0.1) match best, though our reflected light phase curves show intensities approximately one-third of those observed by Kepler. We conclude that a better understanding of zonal transport, cloud radiative feedback, and particle scattering properties is needed to further explain the differences between the modeled and observed reflected light fluxes.
format Preprint
id arxiv_https___arxiv_org_abs_2411_14225
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Reflected-light Phase Curves with PICASO: A Kepler-7b Case Study
Hamill, Colin D.
Johnson, Alexandria V.
Batalha, Natasha
Nag, Rowan
Gao, Peter
Adams, Danica
Kataria, Tiffany
Earth and Planetary Astrophysics
Examining reflected light from exoplanets aids in our understanding of the scattering properties of their atmospheres and will be a primary task of future flagship space- and ground-based telescopes. We introduce an enhanced capability of Planetary Intensity Code for Atmospheric Scattering Observations (PICASO), an open-source radiative transfer model used for exoplanet and brown dwarf atmospheres, to produce reflected light phase curves from three-dimensional atmospheric models. Since PICASO is coupled to the cloud code Virga, we produce phase curves for different cloud condensate species and varying sedimentation efficiencies (fsed) and apply this new functionality to Kepler-7b, a hot Jupiter with phase curve measurements dominated by reflected starlight. We model three different cloud scenarios for Kepler-7b: MgSiO3 clouds only, Mg2SiO4 clouds only, and Mg2SiO4, Al2O3, and TiO2 clouds. All our Virga models reproduce the cloudy region west of the substellar point expected from previous studies, as well as clouds at high latitudes and near the eastern limb, which are primarily composed of magnesium silicates. Al2O3 and TiO2 clouds dominate near the substellar point. We then compare our modeled reflected light phase curves to Kepler observations and find that models with all three cloud condensate species and low sedimentation efficiencies (0.03 - 0.1) match best, though our reflected light phase curves show intensities approximately one-third of those observed by Kepler. We conclude that a better understanding of zonal transport, cloud radiative feedback, and particle scattering properties is needed to further explain the differences between the modeled and observed reflected light fluxes.
title Reflected-light Phase Curves with PICASO: A Kepler-7b Case Study
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2411.14225