Numerical-experiment investigation of coalescence of gaseous protogalactic fragments in triple systems

The numerical-experiment approach in the framework of the general gravitational three-body problem has been used to investigate the dynamical evolution of triple systems of gaseous protogalactic fragments. The masses of the fragments are equal, the initial velocities zero. The initial positions were specified by uniform scanning in the region D of all possible initial configurations. Calculations were continued until the first two-body encounter of the fragments. Different values of the fragment radii at this times were considered, namely, r in the interval [0.001, 0.1]d, where d is the mean diameter of the system. It is shown that for such r the pair of gaseous fragments coalesces in the majority of cases (from 50.2% for r = 0.001d to 96.7% for r = 0.1d). The mean specific angular momentum of their relative motion, which becomes spin angular momentum of the coalescence product, is (0.8 +- 1.0)/centered dot/1029/root/μl cm2sec for the most probable value r = 10l kpc (the masses of the fragments are 5/centered dot/1010μM/circled dot/; l and μ are scale factors), this agreeing in order of magnitude with the specific angular momenta of disk galaxies if l, μ /approximately/ 1. For each value of r, a continuous zone of initial configurations corresponding to coalescences is identified in the region D