Colliding-wind binary

A colliding-wind binary is a binary star system in which the two members are massive stars that emit powerful, radiatively-driven stellar winds. The location where these two winds collide produces a strong shock front that can cause radio, X-ray and possibly synchrotron radiation emission.[1] Wind compression in the bow shock region between the two stellar winds allows dust formation. When this dust streams away from the orbiting pair, it can form a pinwheel nebula of spiraling dust. Such pinwheels have been observed in the Quintuplet Cluster[2]

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.[3] Credit: Chandra Science Center and NASA.

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.[7]

  1. ^ Cite error: The named reference arxiv1006.3540 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference science313_5789_935 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference chandra20070620 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference arxiv1011.0779 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference nrao20050411 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference apjl716_2_L223 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference nasa20070216 was invoked but never defined (see the help page).