The magnetic field of $\zeta$ Ori A

TL;DR

This paper reports spectropolarimetric observations and analysis of the magnetic field in the O star $$ Ori A, confirming its magnetic nature and providing detailed characterization, which enhances understanding of magnetic properties in massive stars.

Contribution

The study confirms the magnetic field in $$ Ori Aa and offers a detailed analysis considering binarity, addressing previous uncertainties in magnetic measurements of O stars.

Findings

Magnetic field detected in $$ Ori Aa.

Characterized magnetic properties of $$ Ori Aa.

Accounted for binarity in magnetic analysis.

Abstract

Magnetic fields play a significant role in the evolution of massive stars. About 7% of massive stars are found to be magnetic at a level detectable with current instrumentation and only a few magnetic O stars are known. Detecting magnetic field in O stars is particularly challenging because they only have few, often broad, lines to measure the field, which leads to a deficit in the knowledge of the basic magnetic properties of O stars. We present new spectropolarimetric Narval observations of $\zeta$ Ori A. We also provide a new analysis of both the new and older data taking binarity into account. The aim of this study was to confirm the presence of a magnetic field in $\zeta$ Ori A. We identify that it belongs to $\zeta$ Ori Aa and characterize it.