New Insights on Jupiter's Deep Water Abundance from Disequilibrium Species

TL;DR

This paper refines the chemical constraints on Jupiter's deep water abundance by introducing a new formulation of the eddy diffusion coefficient, leading to more precise estimates of water enrichment from disequilibrium species.

Contribution

It proposes a novel formulation of the eddy diffusion coefficient based on laboratory studies, improving the accuracy of atmospheric mixing models for giant planets.

Findings

New eddy diffusion coefficient predicts a smooth transition from equator to pole.

Uncertainty in the diffusion coefficient is reduced to less than 25%.

Water enrichment estimates vary between 0.1-0.75 and 3-11 depending on the CO model.

Abstract

The bulk water abundance on Jupiter potentially constrains the planet's formation conditions. We improve the chemical constraints on Jupiter's deep water abundance in this paper. The eddy diffusion coefficient is used to model vertical mixing in planetary atmosphere, and based on laboratory studies dedicated to turbulent rotating convection, we propose a new formulation of the eddy diffusion coefficient for the troposphere of giant planets. The new formulation predicts a smooth transition from the slow rotation regime (near the equator) to the rapid rotation regime (near the pole). We estimate an uncertainty for the newly derived coefficient of less than 25$\%$, which is much better than the one order of magnitude uncertainty used in the literature. We then reevaluate the water constraint provided by CO, using the newer eddy diffusion coefficient. We considered two updated CO kinetic models, one model constrains the water enrichment (relative to solar) between 0.1 and 0.75, while the other constrains the water enrichment between 3 and 11.