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Computational Models of Star Cluster Evolution |
Star clusters in the Galaxy come in several varieties, ranging primarily in their size (number of stars) and distribution within the Galactic gravitational potential. A proper understanding of the observational results of star clusters requires models that are necessarily computational, as the solution of Newton's equations of motion for a large number of masses under their own self-gravity is a complex task, involving the solution of a set of differential equations describing the orbit of each star in the system. While the scientific basis for all star cluster models is based on Newtonian gravity, the details change for different problems. For example, globular star clusters are composed of roughly a half million stars, but are very old and have long since lost any extra gaseous nebulosity. Open star clusters in the Galactic disk however, are smaller (more like 104 stars) and younger, but contain gas clouds that affect overall gravitational force field in which the stars orbit. My work, to date, has focused on an understanding of the energetics of binary star systems and their effects on the overall evolution of globular star clusters. However, I am now involved in another project to study mass segregation in younger clusters, where the operative parameter is choice of initial mass function for the stars at the beginning of the evolution (obviously something which cannot be observed). In both cases, we seek to understand the evolution of star clusters based on core physical variables, using ab initio N-body models.
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