Radio observations of colliding winds in massive stars

TL;DR

This paper reviews radio observations of colliding winds in massive stars, highlighting key systems like WR140, and discusses the binary nature of non-thermal emitters, emphasizing observational strategies and historical context.

Contribution

It provides a comprehensive overview of radio observational evidence for colliding winds in massive stars and discusses recent findings and strategies for identifying new systems.

Findings

First direct observational support for colliding-wind models in the 1990s

Detailed studies of the WR140 system and recent O-star observations

Most non-thermal radio emitters are in binary systems

Abstract

This brief review describes radio observations of colliding winds in massive stars starting with the first direct observational support for the colliding-wind model advanced in the early 1990's to explain non-thermal radio and thermal X-ray emission in some massive stars. Studies of the well-studied and highly-eccentric WR+O star system WR140 are described along with recent observations of O-star systems. Also discussed is the binary nature of almost all massive stars that exhibit non-thermal behavior and some strategies for finding new systems.