Astrophysics and Space Science

, Volume 229, Issue 2, pp 265–299 | Cite as

Effects of gravitational microlensing of binary and multiple stars

  • A. M. Cherepashchuk
  • M. V. Sazhin
  • I. A. Trifalenkov


The observation of microlensing events towards the Large Magellanic Cloud and Galactic Bulge discovers a new population of our Galaxy which is that of dark bodies with masses of the order of 0.1M. Astronomy has now a unique ability: one can use the microlensing as a space telescope with extremely high angular resolution. Here we discuss the opportunity of the application of this ability to observation of close binaries. Stars in a binary system move around their barycenter and as a result the apparent motion is modulated by binary motion. The light curve of this microlensing event becomes nonsymmetrical. If a binary has two stars with different spectral types, one can expect significant variation of color during microlensing effect. Accurate light curves for some typical binaries have been calculated and are presented here. The total fraction of binaries in our Galaxy is around 50%. Therefore one can expect half of the microlensing events to have nonsymmetrical and wavelength depending light curves which would indicate that background star is binary. Our opinion is that the absence of these light curves are due to some selection effect. This leads to an underestimation of the density of the dark body population in our Galaxy by a factor of about two.

Key words

microlensing binary stars gravitation 


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  1. Alcock, C., Akerlof, C.W., Allsman, al.: 1993,Nature V. 365, 621.Google Scholar
  2. Blair, D.G. and Sazhin, M.V.: 1993,Astronomical and Astrophysical Transactions V. 3, 191.Google Scholar
  3. Benetti, S., Pasquini, L., and West, R.M.: 1995,Astron. and Astrophys. V. 294, L37.Google Scholar
  4. Byalko, A.V.: 1969,Astron. Zhurnal 46, 998.Google Scholar
  5. Cherepashchuk, A.M. (ed.): 1989, Catalog of close binaries on the late stages of evolution, Moscow, Moscow State Univ. Publ. House.Google Scholar
  6. Crotts, A.P.S.: 1992,Astrophys. J. 399, L43.Google Scholar
  7. Goncharsky, A.V., Romanov, S.Yu., and Cherepashchuk, A.M.: 1991, Finite-Number Parametric Inverse Problems of Astrophysics, Moscow, Moscow Univ. Press (in Russian).Google Scholar
  8. Glushneva, I.N. (ed.): 1982, Spectrophotometry of bright stars. M., Nauka (in Russian).Google Scholar
  9. Griest, K.: 1991,Astrophys. J. 366, 412.Google Scholar
  10. Mao, S. and Paczinsky, B.: 1991,Astrophys. J. V. 374, L37.Google Scholar
  11. Martynov, D.Ya.: 1969, General Astrophysics, Moscow (in Russian).Google Scholar
  12. Mukhanov, V.F.: 1981,Sov. Phys. Uspekhi, N. 4, p. 133.Google Scholar
  13. Aubourg, E., Bareyre, P., Brehin, al.: 1993,Nature V. 365, 623.Google Scholar
  14. Paczinsky, B.: 1986,Astrophys. J. V. 304, 1.Google Scholar
  15. Postnov, K.A. and Shakura, N.I.: 1994,Pizma v Astron. Zh. V. 13, 300.Google Scholar
  16. Kopal, Z.: 1959, Close Binary Systems, London, Chapman and Hall.Google Scholar
  17. Liebes, R.: 1964,Phys. Rev. B133, 835.Google Scholar
  18. Refsdal, S.: 1964,Mon. Not. R. Astr. Soc. 128, 4.Google Scholar
  19. Sazhin, M.V.: 1987,Astron. Circular, N1500 (in Russian).Google Scholar
  20. Sazhin, M.V., Shulga, V.V., and Gorbatko, N.P.: 1993, in: Quarks-92, Ed. Grigoriev, D., Matveev, V., Rubakov, V., and Tinyakov, P., World Sci.Google Scholar
  21. Sazhin, M.V. and Cherepashchuk, A.M.: 1994,Astronomy Letters V. 20, 613.Google Scholar
  22. Sazhin, M.V. and Cherepashchuk, A.M.: 1995,Astronomy Letters 21, accepted.Google Scholar
  23. Sazhin, M.V. and Sidorov, V.M.: 1989, Preprint N3, MO SAI (in Russian).Google Scholar
  24. Svechnikov, M.A.: 1986, The catalog of orbital elements, masses and luminosities of close binaries, Irkutsk, Irkutsk Univ. Press.Google Scholar
  25. Spiro, M.: 1990, in: Proc. of 25th Intern. Conf. on High Energy Phys., Ed. Phua, K.K. and Yamaguchi, Y., World Sci., II, p. 463.Google Scholar
  26. Trunkovsky, E.M.: 1987,Pizma v Astron. Zh. V. 13, 900.Google Scholar
  27. Udalski, A., Szymanski, M., Kaluzny, J., Kubiak, M., Mateo, M., and Krzeminski, W.: 1994,Astrophys. J. Lett. V. 426, L69.Google Scholar

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • A. M. Cherepashchuk
    • 1
  • M. V. Sazhin
    • 1
  • I. A. Trifalenkov
    • 1
  1. 1.Sternberg Astronomical InstituteMoscowRussia

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