X-raying the Wind–Wind Collisions in HD 168112 and HD 167971
email : g.rauw@uliege.be
Résumé
La binaire O+O à période longue HD 168112 et le système triple HD 167971 sont connus depuis les années 1980 pour leur émission radio synchrotron. Cette émission radio est produite par des électrons relativistes accélérés par les chocs hydrodynamiques de la collision des vents stellaires dans ces systèmes. Ces collisions peuvent également générer une intense émission en rayons X qui varie en fonction de la phase orbitale. Dans des binaires excentriques à longue période orbitale, comme celles étudiées ici, le plasma en aval du choc se trouve dans le régime adiabatique et l’intensité de l’émission X devrait varier comme l’inverse de la séparation orbitale. Ici, nous discutons des observations XMM-Newton de HD 168112 et HD 167971 qui nous permettent de mieux comprendre les propriétés de collisions de vents au sein de ces systèmes.
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.
This work is distributed under the Creative Commons CC BY 4.0 Licence.
Paper presented at the 41st Liège International Astrophysical Colloquium on “The eventful life of massive star multiples,” University of Liège (Belgium), 15–19 July 2024.
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