Magnetic fields, winds and X-rays of massive stars in the Orion Nebula Cluster

TL;DR

This study investigates how magnetic fields influence stellar winds and X-ray emissions in massive OB stars within the Orion Nebula Cluster, combining X-ray observations with spectropolarimetric data to understand magnetic confinement effects.

Contribution

It provides new magnetic field measurements for OB stars in the Orion Nebula Cluster and explores their impact on stellar wind and X-ray emission properties.

Findings

Magnetic fields are detected in some OB stars in the cluster.

Magnetic confinement affects wind structure and X-ray emission.

The study links magnetic properties to X-ray variability.

Abstract

In massive stars, magnetic fields are thought to confine the outflowing radiatively-driven wind, resulting in X-ray emission that is harder, more variable and more efficient than that produced by instability-generated shocks in non-magnetic winds. Although magnetic confinement of stellar winds has been shown to strongly modify the mass-loss and X-ray characteristics of massive OB stars, we lack a detailed understanding of the complex processes responsible. The aim of this study is to examine the relationship between magnetism, stellar winds and X-ray emission of OB stars. In conjunction with a Chandra survey of the Orion Nebula Cluster, we carried out spectropolarimatric ESPaDOnS observations to determine the magnetic properties of massive OB stars of this cluster.