Exoplanets & Exomoons

Coupled Day-Night Models of Exoplanetary Atmospheres

By Keith Cowing
October 15, 2020
Filed under
Coupled Day-Night Models of Exoplanetary Atmospheres
Schematic of the pressure-temperature profile and thermal fluxes in the day side and night side GENESIS model. Incident stellar flux from the top of the day side is absorbed by the day side atmosphere. This heat transfers through the thermal gradient to the night side via a depth dependent wind flux. The internal heat flux from the planetary core is assumed to be the same for both sides of the atmosphere.

We provide a new framework to model the day side and night side atmospheres of irradiated exoplanets using 1-D radiative transfer by incorporating a self-consistent heat flux carried by circulation currents (winds) between the two sides.

The advantages of our model are its physical motivation and computational efficiency, which allows for an exploration of a wide range of atmospheric parameters. We use this forward model to explore the day and night side atmosphere of WASP-76~b, an ultra-hot Jupiter which shows evidence for a thermal inversion and Fe condensation, and WASP-43~b, comparing our model against high precision phase curves and general circulation models.

We are able to closely match the observations as well as prior theoretical predictions for both of these planets with our model. We also model a range of hot Jupiters with equilibrium temperatures between 1000-3000~K and reproduce the observed trend that the day-night temperature contrast increases with equilibrium temperature up to ∼2500~K beyond which the dissociation of H2 becomes significant and the relative temperature difference declines.

Siddharth Gandhi, Adam S. Jermyn
Comments: 20 pages, 7 figures, accepted for publication in MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2010.07303 [astro-ph.EP] (or arXiv:2010.07303v1 [astro-ph.EP] for this version)
Submission history
From: Siddharth Gandhi
[v1] Wed, 14 Oct 2020 18:00:00 UTC (264 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻