Kenji Hamaguchi (UMBC and NASA/GSFC) and Mike Corcoran (CUA and NASA/GSFC)
Hot and Cold Shocked Gas in the Colliding Wind Binary WR 140

Colliding wind binaries are massive stellar systems in which the high Mach number collision of two radiatively-driven winds produces observable signatures over nearly the entire electromagnetic spectrum. Because the opposing flow speeds are high (typically thousands of km/s), the wind-wind collision produces a strong collisionless shock at X-ray emitting temperatures, and in some case formation of low-temperature dust. The revolution of the stars in their orbits causes phase dependent variations in the observed X-ray emission which provides a key diagnostic of mass loss and wind acceleration. We discuss how long-term X-ray monitoring of the evolved dust-producing colliding wind binary WR 140, along with high resolution X-ray spectrometry, provides important information on the dynamics of the shocked gas and the wind density profile.