# Breezing through the space environment of Barnard's Star b

## TL;DR

This study models the stellar wind environment of Barnard's Star b using proxy magnetic fields, revealing it experiences milder wind pressures than closer-in exoplanets, with implications for its habitability.

## Contribution

Introduces a physically realistic stellar wind model for Barnard's Star b using proxy magnetic fields, providing new insights into its space environment.

## Key findings

- Barnard's Star b experiences less intense stellar wind pressure than closer exoplanets.
- Wind conditions are mainly influenced by orbital distance rather than stellar magnetic field strength.
- Dynamic pressure variations can be significant during current sheet crossings.

## Abstract

A physically realistic stellar wind model based on Alfv\'en wave dissipation has been used to simulate the wind from Barnard's Star and to estimate the conditions at the location of its recently discovered planetary companion. Such models require knowledge of the stellar surface magnetic field that is currently unknown for Barnard's Star. We circumvent this by considering the observed field distributions of three different stars that constitute admissible magnetic proxies of this object. Under these considerations, Barnard's Star b experiences less intense wind pressure than the much more close-in planet Proxima~b and the planets of the TRAPPIST-1 system. The milder wind conditions are more a result of its much greater orbital distance rather than in differences in the surface magnetic field strengths of the host stars. The dynamic pressure experienced by the planet is comparable to present-day Earth values, but it can undergo variations by factors of several during current sheet crossings in each orbit. The magnetospause standoff distance would be $\sim$\,$20 - 40$\,\% smaller than that of the Earth for an equivalent planetary magnetic field strength.