Abstract

Thermal emission spectra of exoplanets provide constraints on the chemical compositions, pressure-temperature (P-T) profiles, and energy transport in exoplanetary atmospheres. Accurate inferences of these properties rely on the robustness of the atmospheric retrieval methods. While retrieval codes have provided significant constraints on molecular abundances and temperature profiles in several exoplanetary atmospheres, the constraints on their deviations from thermal and chemical equilibria have yet to be fully explored. HyDRA, our new disequilibrium retrieval framework, is a step in this direction. For a given dataset, the retrieved chemical compositions and P-T profiles are used in tandem with our self-consistent atmospheric model to constrain layer-by-layer deviations from chemical and radiative-convective equilibrium in the observable atmosphere. We demonstrate this on the Hot Jupiter WASP -43b with a high-precision emission spectrum. We retrieve a water vapour mixing ratio that is solar, in agreement with previous studies. With our disequilibrium analysis we find that the dayside P-T profile is consistent with radiative-convective equilibrium and that the derived compositions are also consistent with thermochemical equilibrium. In the era of high precision and high resolution emission spectroscopy, HyDRA provides a path to retrieve disequilibrium phenomena in exoplanetary atmospheres.