# Stellar physics with high-resolution UV spectropolarimetry

## TL;DR

This paper discusses the potential of high-resolution UV spectropolarimetry to advance understanding of stellar magnetism in both hot and cool stars, impacting models of stellar evolution and star-environment interactions.

## Contribution

It highlights the importance of high-resolution UV spectropolarimetric measurements for studying magnetic fields and their effects in different types of stars, proposing a new observational approach.

## Key findings

- UV spectropolarimetry can reveal magnetic field structures in hot stars.
- It provides insights into the magnetic heating of cool star atmospheres.
- Potential to improve models of stellar wind and star-planet interactions.

## Abstract

Current burning issues in stellar physics, for both hot and cool stars, concern their magnetism. In hot stars, stable magnetic fields of fossil origin impact their stellar structure and circumstellar environment, with a likely major role in stellar evolution. However, this role is complex and thus poorly understood as of today. It needs to be quantified with high-resolution UV spectropolarimetric measurements. In cool stars, UV spectropolarimetry would provide access to the structure and magnetic field of the very dynamic upper stellar atmosphere, providing key data for new progress to be made on the role of magnetic fields in heating the upper atmospheres, launching stellar winds, and more generally in the interaction of cool stars with their environment (circumstellar disk, planets) along their whole evolution.