Magnetospheres of Terrestrial Exoplanets and Exomoons: Implications for Habitability and Detection

TL;DR

This study models coupled magnetospheres of terrestrial exoplanets and exomoons, revealing their protective roles in maintaining atmospheres and influencing detectability, with implications for habitability assessments.

Contribution

It introduces a magnetic topological model showing how exoplanet-exomoon magnetospheres interact to protect atmospheres and facilitate atmospheric exchange.

Findings

Exomoon magnetospheres can shield exoplanets from stellar winds.

Magnetic reconnection enables atmosphere exchange between exoplanets and exomoons.

Exomoon magnetospheres influence radio emissions from exoplanets.

Abstract

Characterizing habitable exoplanets and/or their moons is of paramount importance. Here we show the results of our magnetic field topological modeling which demonstrate that terrestrial exoplanet-exomoon coupled magnetospheres work together to protect the early atmospheres of both the exoplanet and the exomoon. When exomoon magnetospheres are within the exoplanet's magnetospheric cavity, the exomoon magnetosphere acts like a protective magnetic bubble providing an additional magnetopause confronting the stellar winds when the moon is on the dayside. In addition, magnetic reconnection would create a critical pathway for the atmosphere exchange between the early exoplanet and exomoon. When the exomoon's magnetosphere is outside of the exoplanet's magnetosphere it then becomes the first line of defense against strong stellar winds, reducing the exoplanet's atmospheric loss to space. A brief discussion is given on how this type of exomoon would modify radio emissions from magnetized exoplanets.