Astronomy Reports

, Volume 62, Issue 4, pp 264–272 | Cite as

The Light-time Effect in the Eclipsing Binaries with Early-type Components U CrB and RW Tau

  • A. I. Khaliullina


A detailed study of the orbital-period variations of the Algol-type eclipsing binaries with earlyspectral- type primary components U CrB and RW Tau has been performed. The period variations in both systems can be described as a superposition of secular and cyclic variations of the period. A secular period increase at a rate of 2.58d × 10−7/year is observed for U CrB, which can be explained if there is a uniform flow of matter from the lower-mass to the higher-mass component, with the total angular momentum conserved. RW Tau features a secular period decrease at a rate of −8.6d × 10−7/year; this could be due to a loss of angular momentum by the binary due to magnetic braking. The cyclic orbital-period variations of U CrB and RWTau can be explained by the motion of the eclipsing binary systems along their long-period orbits. In U CrB, this implies that the eclipsing binary moves with a period of 91.3 years around a third body with mass M3 > 1.13M; in RW Tau, the period of the motion around the third body is 66.6 years, and the mass of the third body is M3 > 1.24M. It also cannot be ruled out that the variations are due to the magnetic cycles of the late-type secondaries. The residual period variations could be a superposition of variations due to non-stationary ejection of matter and effects due to magnetic cycles.


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  1. 1.
    Kh. F. Khaliullin, Sov. Astron. 18, 229 (1974).ADSGoogle Scholar
  2. 2.
    S. Rappaport, F. Verbunt, and P. C. Joss, Astrophys. J. 275, 713 (1983).ADSCrossRefGoogle Scholar
  3. 3.
    N. Ivanova and R. E. Taam, Astrophys. J. 599, 516 (2003).ADSCrossRefGoogle Scholar
  4. 4.
    C. Knigge, I. Baraffe, and J. Patterson, Astrophys. J. Suppl. 194, 28 (2011).ADSCrossRefGoogle Scholar
  5. 5.
    Kh. F. Khaliullin and A. I. Khaliullina, Mon. Not. R. Astron. Soc. 419, 3393 (2012).ADSCrossRefGoogle Scholar
  6. 6.
    Kh. F. Khaliullin and A. I. Khaliullina, Astron. Rep. 57, 517 (2013).ADSCrossRefGoogle Scholar
  7. 7.
    J. H. Applegate, Astrophys. J. 385, 621 (1992).ADSCrossRefGoogle Scholar
  8. 8.
    A. H. Batten, Quart. J. R. Astron. Soc. 5, 145 (1964).ADSGoogle Scholar
  9. 9.
    G. A. Bakos and J. Tremko, J. R. Astron. Soc. 75, 124 (1981).ADSGoogle Scholar
  10. 10.
    S. K. Yerli, M. J. Sarna, S. Zola, R. C. Smith, and G. Tovmassian, Mon. Not. R. Astron. Soc. 342, 1349 (2003).ADSCrossRefGoogle Scholar
  11. 11.
    R. S. Dugan, Contrib. Princeton Univ. Obs., No. 19, 1 (1939).ADSGoogle Scholar
  12. 12.
    F. B. Wood, Astrophys. J. 112, 196 (1950).ADSCrossRefGoogle Scholar
  13. 13.
    T. Borkovits and T. Hegedüs, Astron. Astrophys. Suppl. 120, 63 (1996).ADSCrossRefGoogle Scholar
  14. 14.
    V.D.Grigorenko,S. A. Gadon, S.E. Shurpakov, and I. S. Bryukhanov, Odessa Astron. Publ. 20, 44 (2007).ADSGoogle Scholar
  15. 15.
    A. H. Joy, Publ. Astron. Soc. Pacif. 54, 35 (1942).ADSCrossRefGoogle Scholar
  16. 16.
    G. Grant, Astrophys. J. 129, 62 (1959).ADSCrossRefGoogle Scholar
  17. 17.
    B. B. Bookmayer, Publ. Astron. Soc. Pacif. 89, 533 (1977).ADSCrossRefGoogle Scholar
  18. 18.
    F. Mardirossian, M. Mezzetti, F. Predolin, and G. Giuricin, Astron. Astrophys. Suppl. 40, 57 (1980).ADSGoogle Scholar
  19. 19.
    W. van Hamme and R. E. Wilson, Astron. J. 100, 1981 (1990).ADSCrossRefGoogle Scholar
  20. 20.
    H. Frieboes-Conde and T. J. Herczeg, Astron. Astrophys. Suppl. Ser. 12, 1 (1973).ADSGoogle Scholar
  21. 21.
    V. Šimon, Astron. Astrophys. 319, 886 (1997).ADSGoogle Scholar
  22. 22.
    B. R. N. O. Project—Eclipsing Binaries database, Scholar
  23. 23.
    D. Ya. Martynov, in Variable Stars, Ed. by M. S. Zverev, B. V. Kukarkin, D. Ya. Martynov, P. P. Parenago, N. F. Florya, and V. P. Tsesevich (Gostekhizdat, Moscow, 1947), Vol. 3, p. 464 [in Russian].Google Scholar
  24. 24.
    A. I. Khaliullina and Kh. F. Khaliullin, Sov. Astron. 28, 228 (1984).ADSGoogle Scholar
  25. 25.
    Z. Eker, F. Soudugan, E. Soydugan, S. Bilir, E. YazGökze, I. Steer, M. Tüysüz, T. Şenyüz, and O. Demircan, Astron. J. 149, 131 (2015).ADSCrossRefGoogle Scholar
  26. 26.
    A. I. Khaliullina, Astron. Rep. 59, 717 (2015).ADSCrossRefGoogle Scholar
  27. 27.
    A. I. Khaliullina, Astron. Rep. 60, 807 (2016).ADSCrossRefGoogle Scholar
  28. 28.
    A. I. Khaliullina, Astron. Rep. 61, 612 (2017).ADSCrossRefGoogle Scholar
  29. 29.
    A. I. Khaliullina, Astron. Rep. 61, 859 (2017).ADSCrossRefGoogle Scholar

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© Pleiades Publishing, Ltd. 2018

Authors and Affiliations

  1. 1.Sternberg Astronomical InstituteLomonosov Moscow State UniversityMoscowRussia

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