Contact binary

This article is about contact binary stars. For asteroids, see Contact binary (small Solar System body).

In astronomy, a contact binary is a binary star system whose component stars are so close that they touch each other or have merged to share their gaseous envelopes. A binary system whose stars share an envelope may also be called an overcontact binary.[1][2][3] Almost all known contact binary systems are eclipsing binaries;[4] eclipsing contact binaries are known as W Ursae Majoris variables, after their type star, W Ursae Majoris.[5]

Contact binaries are sometimes confused with common envelopes. However, whereas the configuration of two touching stars in a contact binary has a typical lifetime of millions to billions of years, the common envelope is a dynamically unstable phase in binary evolution that either expels the stellar envelope or merges the binary in a timescale of months to years.[6]

See also

References

  1. contact binary, David Darling, The Internet Encyclopedia of Science. Accessed on line November 4, 2007.
  2. overcontact binary, David Darling, The Internet Encyclopedia of Science. Accessed on line November 4, 2007.
  3. pp. 5153, An Introduction to Astrophysical Fluid Dynamics, Michael J. Thompson, London: Imperial College Press, 2006. ISBN 1-86094-615-1.
  4. p. 231, Stellar Rotation, Jean Louis Tassoul, Andrew King, Douglas Lin, Stephen P. Maran, Jim Pringle, and Martin Ward, Cambridge, UK, New York: Cambridge University Press, 2000. ISBN 0-521-77218-4.
  5. p. 19, Double and Multiple Stars and how to Observe Them, James Mullaney, New York, London: Springer, 2005. ISBN 1-85233-751-6.
  6. Ivanova, N.; Justham, S.; Chen, X.; De Marco, O.; Fryer, C. L.; Gaburov, E.; Ge, H.; Glebbeek, E.; Han, Z.; Li, X. D.; Lu, G.; Podsiadlowski, P.; Potter, A.; Soker, N.; Taam, R.; Tauris, T. M.; van den Heuvel, E. P. J.; Webbink, R. F. (2013). "Common envelope evolution: where we stand and how we can move forward". The Astronomy and Astrophysics Review 21: 59. arXiv:1209.4302. Bibcode:2013A&ARv..21...59I. doi:10.1007/s00159-013-0059-2.
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