Developing Direct Observational Tests of the Formation of Multiple Stellar Populations in Globular Clusters

Michigan State University, East Lansing MI

Investigators

Abstract

The scientists will investigate how dense groups of stars form. The dense groups of stars, known as globular clusters, are some of the oldest objects we know of in our Milky Way galaxy. Traditionally, these dense groups of stars were thought to have formed together at the same time and with the same composition of chemical elements. However, recent observations have found striking variations of the chemical elements among individual stars in these dense groups. This overturns the textbook understanding of how these clusters of stars form. In this program, more precise observational tests of models for cluster formation will be carried out. They will work with undergraduate and graduate college students as well as high school summer students. The work will be communicated to many school groups. The scientist will present the work to the community as a part of revitalizing the Abrams Planetarium, on the Michigan State University campus, which reaches more than 10,000 K-8 students each year. The investigators will develop and carry out observational tests of models for how these different populations of stars formed in the same compact star cluster. A key aspect of these studies will be to observe the youngest known globular clusters in the local universe, which are critical testing grounds for how these objects form. The observational tests that will be carried out include multi-wavelength studies of enriched gas in young star clusters at different ages and optical spectroscopic observations of possible signatures of multiple generations of stars in young star clusters. The results from these observational tests will then be fed back in to models of globular cluster formation and the interpretation of observations of young cluster systems.