57 Cygni is a close binary star[4] system in the constellation Cygnus, located about 530 light years from Earth. It is visible to the naked eye as a blue-white hued star with a baseline apparent visual magnitude of 4.80.[2] The pair have a magnitude difference of 0.34.[4] This system is moving closer to the Earth with a heliocentric radial velocity of −21 km/s.[2]

This is a double-lined spectroscopic binary with an orbital period of 2.85 days and an eccentricity of 0.15.[4] They show a steady change in their longitude of periastron, showing an apsidal period of 203±4 years.[10] The system does not form an eclipsing binary, having the orbital inclination of around 48°.[6] Both components are B-type main-sequence stars with a stellar classification of B5 V.[4]

References

  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. ^ a b c d e f Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  3. ^ Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179.
  4. ^ a b c d e f g Hilditch, R. W. (1973), "The binary system 57 Cygni - apsidal motion and effects of spectral line blending", Monthly Notices of the Royal Astronomical Society, 164 (2): 101–110, Bibcode:1973MNRAS.164..101H, doi:10.1093/mnras/164.2.101.
  5. ^ a b c De Laurentis, M.; et al. (August 2012), "Testing gravitational theories using eccentric eclipsing detached binaries", Monthly Notices of the Royal Astronomical Society, 424 (3): 2371–2379, arXiv:1207.5410, Bibcode:2012MNRAS.424.2371D, doi:10.1111/j.1365-2966.2012.21410.x, S2CID 119109320.
  6. ^ a b Jetsu, L.; et al. (November 1999), "Photometry of V 1794 Cygni between 1975 and 1995", Astronomy and Astrophysics Supplement, 139 (3): 513–523, Bibcode:1999A&AS..139..513J, doi:10.1051/aas:1999397.
  7. ^ Zorec, J.; et al. (July 2009), "Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ1, D) parameters into Teff", Astronomy and Astrophysics, 501 (1): 297–320, arXiv:0903.5134, Bibcode:2009A&A...501..297Z, doi:10.1051/0004-6361/200811147, S2CID 14969137.
  8. ^ a b Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590
  9. ^ "57 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 16 January 2019.
  10. ^ Tapia, M.; Smith, R. C. (November 1979), "On the spectroscopic binary 57 Cygni", Monthly Notices of the Royal Astronomical Society, 189 (3): 551–561, Bibcode:1979MNRAS.189..551T, doi:10.1093/mnras/189.3.551.
Allikas: https://en.wikipedia.org/wiki/57_Cygni
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