# Investigating the origin of the spectral line profiles of the Hot Wolf-Rayet Star WR2

## TL;DR

This study investigates the spectral line profiles of the Wolf-Rayet star WR2, using imaging and spectroscopy, to determine if rotation, magnetic fields, or a companion explain its unusual features.

## Contribution

The paper provides new observational evidence that rules out a companion and magnetic confinement as explanations for WR2's spectral features, favoring intrinsic stellar properties.

## Key findings

- Weak companion contributes minimally to total light
- No intrinsic polarization supports absence of fast rotation
- Magnetic field required for wind confinement is implausibly strong

## Abstract

The hot WN star WR2 (HD6327) has been claimed to have many singular characteristics. To explain its unusually rounded and relatively weak emission line profiles, it has been proposed that WR2 is rotating close to break-up with a magnetically confined wind. Alternatively, the line profiles could be explained by the dilution of WR2's spectrum by that of a companion. In this paper, we present a study of WR2 using near-infrared AO imaging and optical spectroscopy and polarimetry. Our spectra reveal the presence of weak photospheric absorption lines from a ~B2.5-4V companion, which however contributes only ~5-10% to the total light, suggesting that the companion is a background object. Therefore, its flux cannot be causing any significant dilution of the WR star's emission lines. The absence of intrinsic linear continuum polarization from WR2 does not support the proposed fast rotation. Our Stokes V spectrum was not of sufficient quality to test the presence of a moderately strong organized magnetic field but our new modelling indicates that to confine the wind the putative magnetic field must be significantly stronger than was previously suggested sufficiently strong as to make its presence implausible.