Colliding-wind binary

The location where these two winds collide produces a strong shock front that can cause radio, X-ray and possibly synchrotron radiation emission.

[2] The archetype of such a colliding-wind binary system is WR 140 (HD 193793), which consists of a 20 solar mass (M☉) Wolf-Rayet star orbiting about a 50 M☉, spectral class O4–5 main sequence star every 7.9 years.

The high orbital eccentricity of the pair allows astronomers to observe changes in the colliding wind region as their separation varies.

[4][5] Another prominent example of a colliding-wind binary is thought to be Eta Carinae, one of the most luminous objects in the Milky Way galaxy.

[6] The first colliding-wind binary to be detected in the X-ray band outside the Milky Way galaxy was HD 5980, located in the Small Magellanic Cloud.

A composite optical/x-ray image of Eta Carinae and its surrounding nebula taken by the Chandra X-ray Observatory and the Hubble Space Telescope . The blue inner part of the nebula is optical emission, powered by the collision of winds from Eta Carinae and its unseen companion. ^{[

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]} Credit: Chandra Science Center and NASA.