The Application of Solar Flux Transport Modeling to Exoplanet Systems

Earth-size exoplanets are preferentially detected close-in around small stars; Proxima Centauri b, Ross 128 b, and the TRAPPIST-1 planets are newly discovered exoplanets in this class. The effects of magnetic interactions between the host star and such close-in exoplanets are still not well-constrained. We utilize an empirical solar magnetic flux transport model, first developed by Schrijver and colleagues, to explore the possible relationships between stellar properties (e.g. rotation period, radius, flux emergence rate, and meridional and differential flow rates) and the expected surface magnetic flux distributions, along with their evolution over the stellar cycle. The surface field then provides key information about the interplanetary magnetic fields, stellar winds, dynamic activity, and coronal emission, all of which influence the star-planet interactions. We present simulated magnetic flux patterns representing a range of possible exoplanet host stars, including potential observables such as starspots, active regions, and stellar cycle variations. The magnetic and energetic environment at an exoplanet and its impact on the magnetospheric-atmospheric coupling are important components of a planet’s habitability that we expect to constrain further with this application of simulated stellar magnetic activity.