X-rays from the colliding wind binary WR 146

TL;DR

This paper analyzes X-ray emissions from the binary WR 146 using colliding stellar wind models, finding good spectral shape matches but overestimated flux, suggesting a need to revise the mass-loss rate.

Contribution

It introduces a detailed comparison of CSW model spectra with observations of WR 146, highlighting discrepancies and proposing a significant reduction in the mass-loss rate.

Findings

Model spectra match observed shape but overestimate flux

Electron heating affects model-observation agreement

Mass-loss rate must be reduced by a factor of 8-10

Abstract

The X-ray emission from the massive binary WR 146R is analysed in the framework of the colliding stellar wind (CSW) picture. The theoretical CSW model spectra match well the shape of the observed X-ray spectrum of WR 146R but they overestimate considerably the observed X-ray flux (emission measure). This is valid both in the case of complete temperature equalization and in the case of partial electron heating at the shock fronts (different electron and ion temperatures), but, there are indications for a better correspondence between model predictions and observations for the latter. To reconcile the model predictions and observations, the mass-loss rate of WR 146 must be reduced by a factor of 8 - 10 compared to the currently accepted value for this object (the latter already takes clumping into account). No excess X-ray absorption is derived from the CSW modelling.