Probing Wolf-Rayet Winds: Chandra/HETG X-Ray Spectra of WR 6

TL;DR

This study uses deep Chandra/HETGS X-ray spectra to analyze the wind structure and composition of WR 6, revealing insights into the star's wind dynamics, chemical processing, and variability.

Contribution

It provides detailed spectral analysis of WR 6's wind, identifying emission line profiles, elemental abundances, and variability patterns, advancing understanding of massive star winds.

Findings

X-ray emission originates from a uniformly expanding spherical wind

Strong helium-like forbidden lines indicate emission from tens to hundreds of stellar radii

Enhanced sodium abundance suggests nuclear processed material

Abstract

With a deep Chandra/HETGS exposure of WR 6, we have resolved emission lines whose profiles show that the X-rays originate from a uniformly expanding spherical wind of high X-ray-continuum optical depth. The presence of strong helium-like forbidden lines places the source of X-ray emission at tens to hundreds of stellar radii from the photosphere. Variability was present in X-rays and simultaneous optical photometry, but neither were correlated with the known period of the system or with each other. An enhanced abundance of sodium revealed nuclear processed material, a quantity related to the evolutionary state of the star. The characterization of the extent and nature of the hot plasma in WR 6 will help to pave the way to a more fundamental theoretical understanding of the winds and evolution of massive stars.