Nonlinear Alfv\'en Wave Model of Stellar Coronae and Winds from the Sun to M dwarfs

TL;DR

This study models the nonlinear propagation of Alfvén waves in M dwarf atmospheres using MHD simulations, revealing cooler coronae and faster, less massive stellar winds compared to the Sun.

Contribution

It introduces a semi-empirical method based on MHD simulations to describe M dwarf coronae and stellar winds, extending understanding beyond solar models.

Findings

M dwarf coronae are cooler than solar coronae.

M dwarf stellar winds are faster but have lower mass loss rates.

The model links Alfvén wave dynamics to stellar wind properties.

Abstract

M dwarf's atmosphere and wind is expected to be highly magnetized. The nonlinear propagation of Alfv\'en wave could play a key role in both heating the stellar atmosphere and driving the stellar wind. Along this Alfv\'en wave scenario, we carried out the one-dimensional compressive magnetohydrodynamic (MHD) simulation about the nonlinear propagation of Alfv\'en wave from the M dwarf's photosphere, chromosphere to the corona and interplanetary space. Based on the simulation results, we develop the semi-empirical method describing the solar and M dwarf's coronal temperature, stellar wind velocity, and wind's mass loss rate. We find that M dwarfs' coronae tend to be cooler than solar corona, and that M dwarfs' stellar winds would be characterized with faster velocity and much smaller mass loss rate compared to those of the solar wind.