Coupled Day-Night Models of Exoplanetary Atmospheres

TL;DR

This paper introduces a physically motivated, efficient 1-D radiative transfer model for coupled day-night atmospheres of exoplanets, successfully matching observations and predicting temperature contrasts across various hot Jupiters.

Contribution

The paper presents a new coupled day-night atmospheric model that incorporates circulation-driven heat flux, enabling accurate and efficient simulations of exoplanet atmospheres.

Findings

Model closely matches observed phase curves of WASP-76b and WASP-43b.

Reproduces the trend of increasing day-night temperature contrast with temperature up to 2500 K.

Predicts decline in temperature contrast due to H2 dissociation at higher temperatures.

Abstract

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 $\sim$2500~K beyond which the dissociation of H$_2$ becomes significant and the relative temperature difference declines.