Chandra View of Magnetically Confined Wind in HD191612: Theory versus Observations

TL;DR

This study combines high-resolution X-ray observations of the magnetic star HD191612 at different emission phases with 3D MHD simulations, confirming theoretical models of magnetically confined stellar winds through consistent observational and simulated data.

Contribution

It provides the first detailed comparison between self-consistent 3D MHD simulations and high-resolution X-ray observations of HD191612, validating the magnetic wind confinement theory.

Findings

Flux and hardness variations are repeatable over a decade.

Line profiles are typical for magnetic massive stars with no significant shifts.

Simulation results closely match observational data.

Abstract

High-resolution spectra of the magnetic star HD191612 were acquired using the Chandra X-ray observatory at both maximum and minimum emission phases. We confirm the flux and hardness variations previously reported with XMM-Newton, demonstrating the great repeatability of the behavior of HD191612 over a decade. The line profiles appear typical for magnetic massive stars: no significant line shift, relatively narrow lines for high-Z elements, and formation radius at about 2R*. Line ratios confirm the softening of the X-ray spectrum at the minimum emission phase. Shift or width variations appear of limited amplitude at most (slightly lower velocity and slightly increased broadening at minimum emission phase, but within 1--2 sigma of values at maximum). In addition, a fully self-consistent 3D magnetohydrodynamic (MHD) simulation of the confined wind in HD191612 was performed. The simulation results were directly fitted to the data leading to a remarkable agreement overall between them.