A global view on the colliding-wind binary WR 147

Abstract

ABSTRACT We present results from a global view on the colliding-wind binary WR 147. We analysed new optical spectra of WR 147 obtained with the Gran Telescopio Canarias and archive spectra from the Hubble Space Telescope by making use of modern atmosphere models accounting for optically thin clumping. We adopted a grid-modelling approach to derive some basic physical characteristics of both stellar components in WR 147. For the currently accepted distance of 630 pc to WR 147, the values of mass-loss rate derived from modelling its optical spectra are in acceptable correspondence with that from modelling its X-ray emission. However, they give a lower radio flux than observed. A plausible solution for this problem could be the volume filling factor at large distances from the star (radio-formation region) being smaller than that close to the star (optical-formation region). Adopting this, the model can match well both optical and thermal radio emission from WR 147. The global view on the colliding-wind binary WR 147 thus shows that its observational properties in different spectral domains can be explained in a self-consistent physical picture.