Colliding Winds

Early-type stars in close orbit will exhibit violent collisions of their strong stellar winds. (e.g., V444 Cyg, gamma Velorum)

With wind speeds of thousands of km/s, the supersonic collision will heat the gas to millions of Kelvins: X-RAYS

If the stars are close enough together, radiative cooling can alter the dynamics of this collision...
(Stevens, Blondin & Pollock 1992)