Dynamics of Multiple Stellar Populations in Globular Clusters

Indiana University, Bloomington IN

Investigators

Abstract

Globular clusters contain hundreds of thousands of stars confined in a region with a radius of only a few tens of light-years, much more densely packed than the region around our Sun. These clusters are among the oldest objects in the Universe, so they provide important clues to the formation of our Milky Way Galaxy. New observations have shown that stars within these clusters are not all formed at once, as previously thought, and they exhibit a range of chemical compositions. This group will conduct a theoretical study based on computer simulations of the formation and evolution of globular clusters. Students involved in this program will learn valuable computational and data visualization techniques that are broadly applicable beyond astronomy. Many observational studies have now provided strong evidence that most globular clusters host multiple stellar populations characterized by different chemical properties. This discovery represents a major shift in the common view of globular clusters as systems composed of stars with the same chemical composition. The investigators will model the cluster’s dynamical history, so they can trace motions of the stars back to the formation of the stars. They will model of the formation and dynamical changes with time of multiple populations of stars in these globular clusters. This program will carry out extensive simulations to address: 1) the formation of multiple-population clusters and the characterization of the initial structural and kinematical properties of first- and second-generation stars, 2) the early and long-term evolution of the dynamical properties of first- and second-generation stars, 3) the role of internal dynamical processes and the external tidal field of the host galaxy in the evolution of multiple-population clusters, 4) the evolution of the fundamental properties of the cluster's stellar content and how they are affected by the different initial structural properties of multiple populations. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.