The Circumstellar Medium of Massive Stars in Motion

TL;DR

This paper uses numerical simulations to study the circumstellar environments of massive stars, revealing recent evolutionary changes and the dynamics of bow shocks and H II regions, with implications for understanding stellar evolution and explosions.

Contribution

It presents new 2D and 3D simulations of bow shocks and magnetohydrodynamics around massive stars, providing insights into their recent evolutionary history and circumstellar structures.

Findings

Betelgeuse's bow shock is very young, indicating recent evolution from blue to red supergiant.

First magnetohydrodynamic study of the H II region around Zeta Oph.

Developed a grid of bow shock models applicable to various massive stars.

Abstract

The circumstellar medium around massive stars is strongly impacted by stellar winds, radiation, and explosions. We use numerical simulations of these interactions to constrain the current properties and evolutionary history of various stars by comparison with observed circumstellar structures. Two- and three-dimensional simulations of bow shocks around red supergiant stars have shown that Betelgeuse has probably only recently evolved from a blue supergiant to a red supergiant, and hence its bow shock is very young and has not yet reached a steady state. We have also for the first time investigated the magnetohydrodynamics of the photoionised H II region around the nearby runaway O star Zeta Oph. Finally, we have calculated a grid of models of bow shocks around main sequence and evolved massive stars that has general application to many observed bow shocks, and which forms the basis of future work to model the explosions of these stars into their pre-shaped circumstellar medium.