Probing Element Abundance Changes in Galactic Stars

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The compositions of stars in our Milky Way Galaxy hold vital clues to its birth and history of forming stars. Stars make elements in their interiors. At their deaths, stars return the new elements into the gas of the Galaxy. The investigators seek to use abundances of stars, derived from their spectra, to understand how the buildup of elements led to the complex Periodic Table of today. The investigators have three goals. Their first goal is improving the quality of chemical composition analyses. They will obtain basic laboratory data that go into the spectrum analyses. Second, they will significantly augment the number of stars studied in important groups of stars. Through this they will study members of various Galactic star populations. Thirdly, they will provide service to the research and educational communities. They will make the new lab data, and abundance analysis software freely available to all. They will also work with a group of Texas science educators to link astronomical research with their teaching efforts.The investigators will provide very accurate measurements of iron-group element abundances in many metal-poor stars of the halo of our Galaxy. They will derive abundances of carbon, nitrogen, oxygen, and lithium, as well as carbon isotopic ratios in large samples of about 20 open clusters of the Galactic disk. This work will uniquely take advantage of newly-acquired high resolution spectra covering broad regions of both optical and infrared spectral domains. They will search for star streams in the Galaxy by mating optical spectra with kinematics to be provided by the Gaia astrometric satellite. They will also explore this issue with new infrared spectra of warm red giant stars in clusters and in the general field of the Galactic disk. The investigators will continue to release major updates of lab atomic and molecular spectral line data, and to improve our publicly-available spectrum analysis codes.The investigators will continue their long-standing effort to improve the quality of science education in the state of Texas. They will work with a highly-motivated group of secondary science educators. They give talks on the latest astronomical research, and to engage teachers in projects that can be carried back to use in their classrooms. They will also provide opportunities for teachers to participate in telescope usage, to have workshops at McDonald Observatory, and to attend meetings of the American Astronomical Society.