Atmospheric Dynamics of a Near Tidally Locked Earth-Size Planet

TL;DR

This paper explores the atmospheric dynamics of Earth-sized, tidally-locked exoplanets, using Venus as an analog, to improve understanding of their climate evolution and atmospheric characterization.

Contribution

It links Venusian atmospheric studies to exoplanet climate modeling, emphasizing the importance of Venus as a key analog for tidally-locked terrestrial exoplanets.

Findings

Venus provides critical insights into atmospheric dynamics of tidally-locked planets.

Recent climate lessons from Venus inform exoplanet atmospheric models.

Understanding Venus is essential for interpreting terrestrial exoplanet atmospheres.

Abstract

The discovery and characterization of Earth-sized planets that are in, or near, a tidally-locked state are of crucial importance to understanding terrestrial planet evolution, and for which Venus is a clear analog. Exoplanetary science lies at the threshold of characterizing hundreds of terrestrial planetary atmospheres, thereby providing a statistical sample far greater than the limited inventory of terrestrial planetary atmospheres within the Solar System. However, the model-based approach for characterizing exoplanet atmospheres relies on Solar System data, resulting in our limited inventory being both foundational and critical atmospheric laboratories. Present terrestrial exoplanet demographics are heavily biased toward short-period planets, many of which are expected to be tidally locked, and also potentially runaway greenhouse candidates, similar to Venus. Here we describe the rise in the terrestrial exoplanet population and the study of tidal locking on climate simulations. These exoplanet studies are placed within the context of Venus, a local example of an Earth-sized, asynchronous rotator that is near the tidal locking limit. We describe the recent lessons learned regarding the dynamics of the Venusian atmosphere and how those lessons pertain to the evolution of our sibling planet. We discuss the implications of these lessons for exoplanet atmospheres, and outline the need for a full characterization of the Venusian climate in order to achieve a full and robust interpretation of terrestrial planetary atmospheres.