Star Formation For Globular Cluster System

A new model is developed to study the star formation and chemical evolution in globular clusters (GCs) in this thesis.It has long been known from observations that the metallicity distribution of Galactic GCs shows bimodal structure. In recent years the same distribution feature has also been found in other galaxies. How to explain this phenomenon is a challenge to the formation and evolution of GCs.Our model introduces the general equations of chemical evolution used in galaxies to studies of GCs. In this model the important gas outflow caused by the supernova explosion and other processes during the formation of globular clusters is included.Based on such a self-enrichment model,Monte Carlo method is used to simulate the formation and chemical evolution of globular cluster systems,from which a new explanation of the bimodal metallicity distribution can be given. The high metallicity of disk GCs was caused by the particular environment they are situated. Because of the strong interaction wjth the disk,the extent of outflow and star formation efficiency (SFE) of the disk GCs was quite different from the halo GCs,which leads to the significant difference between the metallicity distribution of two classes of GCs. It is also pointed out that the "Pre-enrichment" can't be used to explain the bimodal structure of metallicity distribution of GCs.It is shown as well that this model is successful to apply not only to GCs in our Galaxy,but also to those in other galaxies as they have a universal formation process.