Early-time small-scale structures in hot-exoplanet atmosphere simulations

TL;DR

This paper highlights the importance of small-scale flow structures in hot-exoplanet atmosphere simulations, showing that neglecting them leads to inaccurate predictions of large-scale flow and thermal flux.

Contribution

It demonstrates that early-time small-scale structures significantly influence long-term atmospheric flow and temperature predictions in hot-exoplanet simulations.

Findings

Neglecting small-scale structures results in smoother, less dynamic flows.

Incorrect thermal flux predictions occur if early small-scale features are unresolved.

Small-scale features are critical across various types of hot planets.

Abstract

We report on the critical influence of small-scale flow structures (e.g., fronts, vortices, and waves) that immediately arise in hot-exoplanet atmosphere simulations initialized with a resting state. A hot, 1:1 spin-orbit synchronized Jupiter is used here as a clear example; but, the phenomenon is generic and important for any type of a hot synchronized planet -- gaseous, oceanic, or telluric. When the early-time structures are not captured in simulations (due to, e.g., poor resolution and/or too much dissipation), the flow behavior is markedly different at later times -- in an observationally significant way; for example, the flow at large-scale is smoother and much less dynamic. This results in the temperature field, and its corresponding thermal flux, to be incorrectly predicted in numerical simulations, even when the quantities are spatially averaged.