Astrophysics and Space Science

, Volume 41, Issue 1, pp 63–77 | Cite as

Dynamical evolution of two-component star clusters

  • Masahiro Saito
  • Masanori Yoshizawa


The dynamical evolution of two-component star clusters, each of which is enclosed within a perfectly reflecting sphere, is investigated by numerically solving moment equations derived from the Boltzmann equation. One of the two adopted model clusters evolves, starting from a state of no mass segregation, toward an equilibrium state at a quite slow rate. The other one evolves away from an equilibrium state and its central density increases without limit. The different evolutionary behaviors of the two model clusters are explained by the fact that there exists no equilibrium state for such clusters if the total energy is less than a certain critical value. The critical value increases with increasing total mass fraction of the heavier stars. This is qualitatively the same as Spitzer's theorem (1969) expressed in another way.


Total Energy Equilibrium State Mass Fraction Total Mass Slow Rate 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Antonov, V. A.: 1962,Vestn. Leningr. Gos. Univ. 7, 135.Google Scholar
  2. Dickens, R. J. and Woolley, R.: 1967,Roy. Observ. Bull., No. 128.Google Scholar
  3. Hénon, M.: 1967,Bull. Astron. 2, 91.Google Scholar
  4. Hénon, M.: 1971,Astrophys. Space Sci. 13, 284.Google Scholar
  5. King, I. R.: 1962,Astron. J. 67, 471.Google Scholar
  6. Larson, R. B.: 1969,Monthly Notices Roy. Astron. Soc. 145, 405.Google Scholar
  7. Larson, R. B.: 1970a,Monthly Notices Roy. Astron. Soc. 147, 323.Google Scholar
  8. Larson, R. B.: 1970b,Monthly Notices Roy. Astron. Soc. 150, 93.Google Scholar
  9. Lynden-Bell, D.: 1967,Monthly Notices Roy. Astron. Soc. 136, 101.Google Scholar
  10. Lynden-Bell, D. and Wood, R.: 1968,Monthly Notices Roy. Astron. Soc. 138, 495 (referred to as LW).Google Scholar
  11. Michie, R. W.: 1963,Monthly Notices Roy. Astron. Soc. 126, 499.Google Scholar
  12. Michie, R. W. and Bodenheimer, P. H.: 1963,Monthly Notices Roy. Astron. Soc. 126, 269.Google Scholar
  13. Oort, J. H. and van Herk, G.: 1959,Bull. Astron. Inst. Neth. 14, 299.Google Scholar
  14. Prata, S. W.: 1971a,Astron. J. 76, 1017.Google Scholar
  15. Prata, S. W.: 1971b,Astron. J. 76, 1029.Google Scholar
  16. Rohlfs, K.: 1961,Z. Astrophys. 53, 155.Google Scholar
  17. Saslaw, W. C. and De Young, D. S.: 1971,Astrophys. J. 170, 423.Google Scholar
  18. Spitzer, L., Jr.: 1969,Astrophys. J. 158, L139.Google Scholar
  19. Spitzer, L., Jr. and Hart, M. H.: 1971,Astrophys. J. 166, 483 (referred to as SH).Google Scholar
  20. Spitzer, L., Jr. and Thuan, T. X.: 1972,Astrophys. J. 175, 31.Google Scholar
  21. Von Hoerner, S.: 1957,Astrophys. J. 125, 451.Google Scholar
  22. Von Hoerner, S.: 1968,Bull. Astron. 3, 147.Google Scholar
  23. Woolley, R.: 1954,Monthly Notices Roy. Astron. Soc. 114, 191.Google Scholar
  24. Woolley, R.: 1956,Monthly Notices Roy. Astron. Soc. 116, 296.Google Scholar

Copyright information

© D. Reidel Publishing Company 1976

Authors and Affiliations

  • Masahiro Saito
    • 1
  • Masanori Yoshizawa
    • 1
  1. 1.Dept. of AstronomyKyoto UniversityKyotoJapan

Personalised recommendations