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]

See also

• Struve-Sahade effect
• Cosmic wind
• Stellar wind
• Solar wind
• Planetary wind
• Stellar-wind bubble
• Pulsar wind nebula
• Galactic superwind
• Superwind

References

1. Volpi, Delia; Blomme, Ronny; De Becker, Michael; Rauw, Gregor (December 2010). "Non-thermal radio emission from colliding-wind binaries: modelling Cyg OB2 No. 8A and No. 9". Proceedings of the International Astronomical Union. 6: 638–639. arXiv:1012.3403. Bibcode:2011IAUS..272..638V. doi:10.1017/S1743921311011689. S2CID 7269006.
2. Tuthill, Peter; et al. (August 18, 2006). "Pinwheels in the Quintuplet Cluster". Science. 313 (5789): 935. arXiv:astro-ph/0608427. Bibcode:2006Sci...313..935T. CiteSeerX 10.1.1.255.6805. doi:10.1126/science.1128731. PMID 16917053. S2CID 17793345. Retrieved 2011-01-14.
3. "Eta Carinae: New View of a Doomed Star". Chandra. June 20, 2007. Retrieved 2011-01-18.
4. Dougherty, S. M.; Trenton, V.; Beasley, A. J. (November 2010). "The orbit and distance of WR140". Bulletin de la Société Royale des Sciences de Liège. 80: 658. arXiv:1011.0779. Bibcode:2011BSRSL..80..658D.
5. Finley, Dave (April 11, 2005). "Scientists Track Collision of Powerful Stellar Winds". National Radio Astronomy Observatory. Retrieved 2011-01-14.
6. Groh, J. H.; Madura, T. I.; Owocki, S. P.; Hillier, D. J.; Weigelt, G. (June 2010). "Is Eta Carinae a Fast Rotator, and How Much Does the Companion Influence the Inner Wind Structure?". The Astrophysical Journal Letters. 716 (2): L223 – L228. arXiv:1006.4816. Bibcode:2010ApJ...716L.223G. doi:10.1088/2041-8205/716/2/L223. S2CID 119188874.
7. Naeye, Bob (February 16, 2007). "First X-Ray Detection of a Colliding-Wind Binary Beyond Milky Way". NASA, Goddard Space Flight Center.