Wolf-Rayet Colliding Wind Binaries

TL;DR

This paper reviews Wolf-Rayet stars, especially in colliding wind binaries, highlighting their energetic winds, extreme phenomena, and the intriguing production of warm dust, with a focus on understanding the underlying physics.

Contribution

It provides a comprehensive overview of Wolf-Rayet colliding wind binaries and discusses the mechanisms behind their unique phenomena, including dust formation.

Findings

Wolf-Rayet stars have high mass-loss rates and energetic winds.

Colliding wind binaries produce observable signatures across multiple wavelengths.

Warm dust formation is linked to carbon-rich Wolf-Rayet stars in binaries.

Abstract

Wolf-Rayet stars embody the final stable phase of the most massive stars immediately before their evolution is terminated in a supernova explosion. They are responsible for some of the most extreme and energetic phenomena in stellar physics, driving fast and dense stellar winds that are powered by extraordinarily high mass-loss rates arising from their near Eddington limit luminosity. When found in binary systems comprised of two hot wind-driving components, a colliding wind binary (CWB) is formed, manifesting dramatic observational signatures from the radio to X-rays. Among the wealth of rare and exotic phenomenology associated with CWBs, perhaps the most unexpected is the production of copious amounts of warm dust. A necessary condition seems to be one binary component being a carbon-rich WR star -- providing favorable chemistry for dust nucleation from the wind -- however a detailed understanding of the physics underlying this phenomenon has not been established.