Abstract
In dynamical models for open clusters, virial equilibrium is not achieved over the violent relaxation time scale τvr. The stars form an equilibrium distribution in (ɛ, ɛζ, l) space, where ɛ and l are the energy and angular momentum per unit stellar mass in the combined field of the Galaxy and cluster and ɛζ is the energy of motion perpendicular to the Galactic plane per unit mass of cluster stars in the gravitational field of the Galaxy. This distribution of stars changes little when t>τvr. The stellar phase-space distribution corresponding to this type of equilibrium and the regular cluster potential vary periodically (or quasi-periodically) with time. This phase-space equilibrium is probably possible due to an approximate balance in the stellar transitions between phase-space cells over times equal to the oscillation period for the regular cluster field.
Similar content being viewed by others
References
V. M. Danilov, Astron. Zh. 76, 93 (1999).
H. E. Kandrup, M. E. Mahon, and H. Smith, Jr., Astron. Astrophys. 271, 440 (1993).
H. E. Kandrup, Astrophys. J. 500, 120 (1998).
S. Chandrasekhar, Principles of Stellar Dynamics (Univ. Chicago Press, Chicago, 1942; Inostrannaya Literatura, Moscow, 1948).
D. Lynden-Bell, Mon. Not. R. Astron. Soc. 136, 101 (1967).
W. C. Saslaw, Gravitational Physics of Stellar and Galactic Systems (Cambridge Univ. Press, Cambridge, 1985; Mir, Moscow, 1989).
V. M. Danilov, Astron. Zh. 74, 188 (1997).
S. A. Kutuzov and L. P. Osipkov, Astron. Zh. 57, 28 (1980).
V. M. Danilov, Pis’ma Astron. Zh. 23, 365 (1997).
I. R. King, Astrophys. J. 67, 471 (1962).
D. W. Marquardt, J. Soc. Indust. Appl. Math. 11, 431 (1963).
Author information
Authors and Affiliations
Additional information
__________
Translated from Astronomicheski\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \) Zhurnal, Vol. 77, No. 5, 2000, pp. 345–356.
Original Russian Text Copyright © 2000 by Danilov.
Rights and permissions
About this article
Cite this article
Danilov, V.M. Equilibrium phase-space density distribution in numerical dynamical models of open clusters. Astron. Rep. 44, 298–308 (2000). https://doi.org/10.1134/1.163853
Received:
Issue Date:
DOI: https://doi.org/10.1134/1.163853