Physics of star-planet magnetic interactions

TL;DR

This paper reviews the physical principles of star-planet magnetic interactions, highlighting effects like aurorae, heating, and planetary migration, with a focus on Alfvén wings and their implications for exoplanet systems.

Contribution

It provides a comprehensive overview of the fundamental physics of star-planet magnetic interactions, emphasizing the role of Alfvén wings in exosystems.

Findings

Magnetic interactions can cause planetary heating and migration.

Alfvén wings are key to understanding star-planet magnetic coupling.

Multiple effects influence exoplanetary environments and star activity.

Abstract

Magnetic interactions between a planet and its environment are known to lead to aurorae and shocks in the solar system. The large number of close-in exoplanets that have been discovered so far triggered a renewed interest in understanding magnetic interactions in other star-planet systems. Multiple magnetic effects were then unveiled, such as planet inflation or heating, planet migration, planetary material escape, and even some modifications of the host star apparent activity. Our goal here is to lay out the basic physical principles underlying star-planet magnetic interactions. We first briefly review the hot exoplanets' population as we know it. We then move to a general description of star-planet magnetic interactions, and finally focus on the fundamental concept of Alfv\'en wings and its implication for exosystems.