Contact binary: Difference between revisions
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{{Short description|Binary star system whose component stars are very close}} |
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{{About|contact binary stars| |
{{About|contact binary stars|comets and minor planets|Contact binary (small Solar System body)}} |
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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.<ref>[http://www.daviddarling.info/encyclopedia/C/contact_binary.html contact binary], David Darling, ''The Internet Encyclopedia of Science''. Accessed on line November 4, 2007.</ref><ref>[http://www.daviddarling.info/encyclopedia/O/overcontact_binary.html overcontact binary], David Darling, ''The Internet Encyclopedia of Science''. Accessed on line November 4, 2007.</ref><ref>pp. 51–53, ''An Introduction to Astrophysical Fluid Dynamics'', Michael J. Thompson, London: Imperial College Press, 2006. ISBN 1-86094-615-1.</ref> Almost all known contact binary systems are [[Binary star#Eclipsing binaries|eclipsing binaries]];<ref>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.</ref> eclipsing contact binaries are known as [[W Ursae Majoris variables]], after their type star, [[W Ursae Majoris]].<ref>p. 19, ''Double and Multiple Stars and how to Observe Them'', James Mullaney, New York, London: Springer, 2005. ISBN 1-85233-751-6.</ref> |
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[[File:An artist’s impression of the hottest and most massive touching double star.jpg|thumb|upright=1.1|right|Artist's rendering of the massive contact binary star [[VFTS 352]], located in the [[Large Magellanic Cloud]]]] |
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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.<ref name=DarlingBinary/><ref name=Thompson2006/> The term "contact binary" was introduced by astronomer [[Gerard Kuiper]] in 1941.<ref name=Kuiper1941/> Almost all known contact binary systems are [[Binary star#Eclipsing binaries|eclipsing binaries]];<ref name=Tassoul2000/> eclipsing contact binaries are known as [[W Ursae Majoris variables]], after their archetype star, [[W Ursae Majoris]].<ref name=Mullaney2005/> |
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| ⚫ | Contact binaries are |
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In a contact binary, both stars have filled their [[Roche lobe]]s, allowing the more massive primary component to transfer both mass and luminosity to the secondary member. As a result, the components in a contact binary often have similar [[effective temperature]]s and luminosities, regardless of their respective masses. The rate of energy transfer between the components is dependent on their mass ratio and luminosity ratio. In cases where the stars are in geometric contact but the thermal contact is poor, there can exist wide differences between their respective temperatures.<ref name=Csizmadia2004/> |
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| ⚫ | Contact binaries are not to be confused with [[common envelope]]s. 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.<ref name=Ivanova2013/> |
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==See also== |
==See also== |
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*[[Contact binary ( |
* [[Contact binary (small Solar System body)]], two asteroids gravitating toward each other until they touch. |
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* [[HR 5171]], a [[Hypergiant|yellow hypergiant]] previously thought to be a contact binary. |
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* [[Interacting binary star]] |
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* [[KIC 9832227]], a contact binary and a previous candidate for stellar merger. |
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* [[Luminous red nova]], e.g. [[V1309 Scorpii]] (2008), may result from the merger of a contact binary. |
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* [[MY Camelopardalis]], a contact binary that is already sharing an atmosphere with each other |
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* [[VFTS 352]], a massive contact binary in the [[Tarantula Nebula]]. |
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==References== |
==References== |
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<references> |
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{{reflist}} |
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<ref name=Csizmadia2004>{{cite journal |
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| title=On the properties of contact binary stars |
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| last1=Csizmadia | first1=Sz. | last2=Klagyivik | first2=P. |
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| journal=Astronomy and Astrophysics |
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| volume=426 | pages=1001–1005 | date=November 2004 |
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| issue=3 | arxiv=astro-ph/0408049 | bibcode=2004A&A...426.1001C |
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| doi=10.1051/0004-6361:20040430 | doi-access=free}}</ref> |
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<ref name=DarlingBinary>{{Cite web |
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| url=http://www.daviddarling.info/encyclopedia/B/binarystar.html |
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| title=binary star | last=Darling | first=David |
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| website=www.daviddarling.info | access-date=2019-05-06 }}</ref> |
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<ref name=Thompson2006>{{cite book |
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{{Astronomy-stub}} |
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| title=An Introduction to Astrophysical Fluid Dynamics |
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| first=Michael J. | last=Thompson |
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| publication-place=London | publisher=Imperial College Press |
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| pages=51–53 | year=2006 | isbn=1-86094-615-1 }}</ref> |
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<ref name=Tassoul2000>{{cite book |
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| title=Stellar Rotation | page=231 |
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| first1=Jean Louis | last1=Tassoul | first2=Andrew | last2=King |
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| first3=Douglas | last3=Lin | first4=Stephen P. | last4=Maran |
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| first5=Jim | last5=Pringle | first6=Martin | last6=Ward |
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| display-authors=1 | publication-place=Cambridge, UK, New York |
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| publisher=Cambridge University Press |
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| year=2000 | isbn=0-521-77218-4 }}</ref> |
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<ref name=Mullaney2005>{{cite book |
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| title=Double and Multiple Stars and how to Observe Them |
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| first=James | last=Mullaney |
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| publication-place=New York, London |
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| publisher=Springer | page=19 |
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| year=2005 | isbn=1-85233-751-6 }}</ref> |
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<ref name=Ivanova2013>{{cite journal |
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| last1=Ivanova | first1=N. | last2=Justham | first2=S. |
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| last3=Chen | first3=X. | last4=De Marco | first4=O. |
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| last5=Fryer | first5=C. L. | last6=Gaburov | first6=E. |
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| last7=Ge | first7=H. | last8=Glebbeek | first8=E. |
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| last9=Han | first9=Z. | last10=Li | first10=X. D. |
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| last11=Lu | first11=G. | last12=Podsiadlowski | first12=P. |
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| last13=Potter | first13=A. | last14=Soker | first14=N. |
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| last15=Taam | first15=R. | last16=Tauris | first16=T. M. |
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| last17=van den Heuvel | first17=E. P. J. | last18=Webbink | first18=R. F. |
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| title=Common envelope evolution: where we stand and how we can move forward |
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| display-authors=1 | journal=The Astronomy and Astrophysics Review |
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| year=2013 | volume=21 | article-number=59 |
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| bibcode=2013A&ARv..21...59I | arxiv=1209.4302 |
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| doi=10.1007/s00159-013-0059-2 }}</ref> |
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<ref name=Kuiper1941>{{cite journal |
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| url=http://articles.adsabs.harvard.edu/pdf/1941ApJ....93..133K |
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| last1=Kuiper | first1=Gerard P. |
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| title=On the Interpretation of β Lyrae and Other Close Binaries |
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| journal=Astrophysical Journal |
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| year=1941 | volume=93 | pages=133 |
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| bibcode=1941ApJ....93..133K |
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| doi=10.1086/144252 |doi-access=free}}</ref> |
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</references> |
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{{Binary stars}} |
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Latest revision as of 01:21, 23 August 2026
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] The term "contact binary" was introduced by astronomer Gerard Kuiper in 1941.[3] Almost all known contact binary systems are eclipsing binaries;[4] eclipsing contact binaries are known as W Ursae Majoris variables, after their archetype star, W Ursae Majoris.[5]
In a contact binary, both stars have filled their Roche lobes, allowing the more massive primary component to transfer both mass and luminosity to the secondary member. As a result, the components in a contact binary often have similar effective temperatures and luminosities, regardless of their respective masses. The rate of energy transfer between the components is dependent on their mass ratio and luminosity ratio. In cases where the stars are in geometric contact but the thermal contact is poor, there can exist wide differences between their respective temperatures.[6]
Contact binaries are not to be confused with common envelopes. 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.[7]
See also
[edit]- Contact binary (small Solar System body), two asteroids gravitating toward each other until they touch.
- HR 5171, a yellow hypergiant previously thought to be a contact binary.
- Interacting binary star
- KIC 9832227, a contact binary and a previous candidate for stellar merger.
- Luminous red nova, e.g. V1309 Scorpii (2008), may result from the merger of a contact binary.
- MY Camelopardalis, a contact binary that is already sharing an atmosphere with each other
- Thorne–Żytkow object, a type of star wherein a red giant or supergiant contains a neutron star at its core.
- VFTS 352, a massive contact binary in the Tarantula Nebula.
References
[edit]- ↑ Darling, David. "binary star". www.daviddarling.info. Retrieved 2019-05-06.
- ↑ Thompson, Michael J. (2006). An Introduction to Astrophysical Fluid Dynamics. London: Imperial College Press. pp. 51–53. ISBN 1-86094-615-1.
- ↑ Kuiper, Gerard P. (1941). "On the Interpretation of β Lyrae and Other Close Binaries". Astrophysical Journal. 93: 133. Bibcode:1941ApJ....93..133K. doi:10.1086/144252.
- ↑ Tassoul, Jean Louis; et al. (2000). Stellar Rotation. Cambridge, UK, New York: Cambridge University Press. p. 231. ISBN 0-521-77218-4.
- ↑ Mullaney, James (2005). Double and Multiple Stars and how to Observe Them. New York, London: Springer. p. 19. ISBN 1-85233-751-6.
- ↑ Csizmadia, Sz.; Klagyivik, P. (November 2004). "On the properties of contact binary stars". Astronomy and Astrophysics. 426 (3): 1001–1005. arXiv:astro-ph/0408049. Bibcode:2004A&A...426.1001C. doi:10.1051/0004-6361:20040430.
- ↑ Ivanova, N.; et al. (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.