A Focused Test of Whether Neutron-Capture Elements Are Another Expression of the Multiple Populations Phenomenon in Globular Clusters

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Globular clusters are groups of hundreds of thousands of stars. There are more than 100 globular clusters orbiting our Milky Way galaxy. The atomic elements found in stars in globular clusters retain the chemical fingerprints of the earliest generations of stars. These elements offer a glimpse into the ways that nature formed stars in the early Universe and produced the heavy elements (iron, uranium, etc.) like those found on Earth today. This investigator will collect and interpret new observational data on trace elements found in five globular clusters. These clusters were formed prior to the assembly of our galaxy. Abundance variations among the heavy elements may signal another expression of the multiple populations phenomenon in globular clusters. These variations are not predicted by current models of globular cluster formation and evolution. New optical spectroscopy data collected using the M2FS spectrograph at the Magellan Telescopes will settle the issue. The investigator will perform observations that will conclusively confirm or refute previous ideas based on lower-quality spectroscopic data. If confirmed, the community will gain a new tool to guide models of globular cluster formation and evolution. If refuted, the community may refocus its efforts to develop models that fully explain the chemical and dynamical properties of globular clusters in the Milky Way.This project will also result in the development of a new introductory course that explores the connections between heavy elements forged in ancient stars and the nuclear weapons that have shaped global politics over the last few generations. This course would reach a broad audience of undergraduates at the University of Michigan, including many students who are not majoring in one of the STEM disciplines. The course will introduce students to the role of science in the public arena, articulated specifically through the compelling story of how stardust from ancient supernovae became the key ingredient in the nuclear arms race. This will increase scientific literacy, enhance public engagement with science and technology, and improve the preparedness of future leaders.