Astronomy Reports

, Volume 59, Issue 6, pp 563–572 | Cite as

Superorbital variability of the X-ray flux in the Be-donor binaries SXP 138, GX-304, and γ Cas

  • A. A. Chashkina
  • P. K. Abolmasov
  • A. V. Biryukov
  • N. I. Shakura


RXTE observations of the X-ray binary systems SXP 138, GX-304, and γ Cas in 1997–2011 have shown for the first time that these objects (X-ray binaries with Be donors) display X-ray flux variations on timescales of ∼1000 days. This timescale is about 10 times longer than their orbital periods, and is comparable to the total time of the observations. The observed variations are apparently not strictly periodic and represent stochastic variability, as is characteristic of such systems in the optical. γ Cas is considered as an example. The series of optical observations of this system available in the AAVSO database covers 78 years, and is much longer than the timescale of the variability studied. Our analysis of this series has shown that γ Cas variability on a timescale of tens of years is predominantly stochastic with a power-law spectrum.


Orbital Period Neutron Star Light Curve Astronomy Report Pulsation Period 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    P. Reig, Astrophys. Space Sci. 332, 1 (2011).CrossRefADSGoogle Scholar
  2. 2.
    N. V. Raguzova and S. B. Popov, Astron. Astrophys. Trans. 24, 151 (2005).CrossRefADSGoogle Scholar
  3. 3.
    J. L. Galache, R. H. D. Corbet, M. J. Coe, S. Laycock, M. P. E. Schurch, C. Markwardt, F. E. Marshall, and J. Lochner, Astrophys. J. Suppl. Ser. 189, 177 (2008)Google Scholar
  4. 4.
    A. F. Rajoelimanana, P. A. Charles, and A. Udalski, Mon. Not. R. Astron. Soc. 413, 1600 (2011).CrossRefADSGoogle Scholar
  5. 5.
    R. H. D. Corbet and H. A. Krimm, Astrophys. J. 45, 778 (2013).Google Scholar
  6. 6.
    R. Corbet and H. A. Krimm, in Proceedings of the HEAD Meeting No. 14 of American Astronomical Society (Am. Astron. Soc., 2014), Abstract No. 122.02.Google Scholar
  7. 7.
    S. A. Farell, R. K. Sood, and P. M. O’Neill, Mon. Not. R. Astron. Soc. 367, 1457 (2006).CrossRefADSGoogle Scholar
  8. 8.
    C. Alcock, Mon. Not. R. Astron. Soc. 321, 678 (2001).CrossRefADSGoogle Scholar
  9. 9.
    P. C. Schmidtke and A. P. Cowley, Astron. J. 132, 919 (2006).CrossRefADSGoogle Scholar
  10. 10.
    J. Ziolkowski, Mem. Soc. Astron. Ital. 73, 1038 (2002); arXiv:0208455 [astro-ph] (2002).ADSGoogle Scholar
  11. 11.
    Q. Z. Liu, J. van Paradijs, and E. P. J. van den Heuvel, Astron. Astrophys. Suppl. Ser. 147, 25 (2000).CrossRefADSGoogle Scholar
  12. 12.
    A. Secchi, Astron. Nachr. 68, 63 (1866).CrossRefADSGoogle Scholar
  13. 13.
    P. Harmanec, P. Habuda, S. Štefl, P. Hadrava, D. Korčáková, P. Koubskí, J. Krtička, J. Kubát, P. Škoda, M. Šlechta, and M. Wolf, Astron., Astron. Astrophys. 364, L85Google Scholar
  14. 14.
    H. Klus, W. C. G. Ho, M. J. Coe, R.H.D. Corbet, and L. J. Townsend, Mon. Not. R. Astron.Soc. 437, 3863 (2014).CrossRefADSGoogle Scholar
  15. 15.
    N. R. Lomb, Astrophys. Space Sci. 39, 447 (1976).CrossRefADSGoogle Scholar
  16. 16.
    J. D. Scargle, Astrophys. J. 263, 835 (1982).CrossRefADSGoogle Scholar
  17. 17.
    A. Schuster, Terr. Magn. Atmos. Elect. 3, 13 (1898).CrossRefGoogle Scholar
  18. 18.
    V. Yu. Terebizh, Time Series Analysis in Astrophysics (Nauka, Moscow, 1992) [in Russian].Google Scholar

Copyright information

© Pleiades Publishing, Ltd. 2015

Authors and Affiliations

  • A. A. Chashkina
    • 1
  • P. K. Abolmasov
    • 1
  • A. V. Biryukov
    • 1
    • 2
  • N. I. Shakura
    • 1
  1. 1.Sternberg Astronomical InstituteLomonosov Moscow State UniversityMoscowRussia
  2. 2.Kazan (Volga region) Federal UniversityKazanRussia

Personalised recommendations