Coalescence and Star Formation in Collapsing Flattened Systems
We report on the results of N-body simulations of star formation resulting from mergers during the collapse of dynamically cold, Ñattened systems of cloudlets. Such evolution is expected to occur in several models of cluster star formation. As was found previously in the case of spherical systems, the resulting star clusters have half-mass radii that are signiÐcantly smaller than the initial values for the systems. Stars that form early in the collapse have large Ðnal orbital radii and retain a
... strong memory of the initial ellipticity of the system. Stars that form later have smaller Ðnal radii and retain less memory. If we examine only those stars within the Ðnal half-mass radii of the models, we Ðnd that they follow a much less ellipsoidal distribution than do stars at larger radii. Their ellipticities, however, generally exceed those of young, dynamically unevolved massive star clusters in the LMC. The best comparisons with the observed ellipticities are found in models for which the initial system minor-to-major axis ratios system kinetic-to-potential energy ratios covering factors or initial cloud b/a Z 0.2, Q Z 0.