On the Collapse and Violent Relaxation of Protoglobular Clusters
Abstract
During the formation of stellar systems such as globular clusters, lowmass subcondensations which eventually form stars must retain a geometric size throughout the collapse process that is small compared to the characteristic distance separating them. If the local velocity dispersion of the subcondensations is small, the overall dimension of the system can decrease substantially before reaching a dynamical equilibrium state. The maximum collapse factor is deduced by examining the growth of the velocity dispersion and the spread in arrival times at the origin caused by local and global fluctuations. It is shown, analytically as well as in a series of Nbody simulations, that the maximum reduction in the characteristic dimension of a system of N fragments with an initial homogeneous distribution subject to N exp 1/2 fluctuations is proportional to N exp 1/3. Direct physical collisions between lowmass subcondensations are therefore unlikely to occur in protoglobular clusters. The results are discussed in the context of fragmentation and violent relaxation.
 Publication:

The Astrophysical Journal
 Pub Date:
 January 1988
 DOI:
 10.1086/165895
 Bibcode:
 1988ApJ...324..288A
 Keywords:

 Computational Astrophysics;
 Globular Clusters;
 Gravitational Collapse;
 Molecular Relaxation;
 Star Formation;
 Stellar Evolution;
 Many Body Problem;
 Stellar Magnitude;
 Stellar Mass;
 Stellar Structure;
 Velocity Distribution;
 Astrophysics;
 CLUSTERS: GLOBULAR;
 STARS: FORMATION