Winds of Planet Hosting Stars

TL;DR

This paper reconstructs magnetic fields of exoplanet host stars and simulates their stellar winds to understand star-planet interactions and potential habitability, using adapted solar wind models for other stars.

Contribution

It introduces a method to reconstruct stellar magnetic fields from spectropolarimetric data and applies wind simulations to a specific star, expanding stellar wind modeling beyond the Sun.

Findings

Wind velocity structures are complex and correlate with magnetic topology.

Simulations provide insights into star-planet space weather interactions.

Preliminary results for $ au$ Bo"otis$ show magnetic influence on wind behavior.

Abstract

The field of exoplanetary science is one of the most rapidly growing areas of astrophysical research. As more planets are discovered around other stars, new techniques have been developed that have allowed astronomers to begin to characterise them. Two of the most important factors in understanding the evolution of these planets, and potentially determining whether they are habitable, are the behaviour of the winds of the host star and the way in which they interact with the planet. The purpose of this project is to reconstruct the magnetic fields of planet hosting stars from spectropolarimetric observations, and to use these magnetic field maps to inform simulations of the stellar winds in those systems using the Block Adaptive Tree Solar-wind Roe Upwind Scheme (BATS-R-US) code. The BATS-R-US code was originally written to investigate the behaviour of the Solar wind, and so has been altered to be used in the context of other stellar systems. These simulations will give information about the velocity, pressure and density of the wind outward from the host star. They will also allow us to determine what influence the winds will have on the space weather environment of the planet. This paper presents the preliminary results of these simulations for the star $\tau$ Bo\"otis, using a newly reconstructed magnetic field map based on previously published observations. These simulations show interesting structures in the wind velocity around the star, consistent with the complex topology of its magnetic field.