X-raying the wind-wind collisions in HD 168112 and HD 167971

Abstract

The O-type long-period binary HD 168112 and triple HD 167971 star systems have been known for several decades for their non-thermal synchrotron radio emission. This emission arises from relativistic electrons accelerated in the hydrodynamic shocks of the wind collisions in these systems. Such wind collisions are expected to produce a strong X-ray emission that varies as a function of orbital phase. In wide eccentric binaries, such as our targets, the X-ray emission arises from an adiabatic plasma and its intensity should scale as the inverse of the orbital separation. We present a set of XMM-Newton observations of these systems which help us gain insight into the properties of their wind interactions.

in French language. Accepted for publication in the Bulletin de la Société Royale des Sciences de Liège, Proceedings of the 41st Liège Astrophysical Colloquium, held in Liège 15-19 July 2024, edited by Y. Nazé, & E. Bozzo