M.S. Astro Thesis Talk: Angela Beaty - "Kinematic Analysis of Chemically-Peculiar, Metal-Poor Stars in the Milky Way Halo"

M.S. Astro Thesis Talk: Angela Beaty

Title: Kinematic Analysis of Chemically-Peculiar, Metal-Poor Stars in the Milky Way Halo

Abstract:

Models for galaxy formation predict that galaxies form through the ongoing assembly of small dwarf galaxies, and observations have confirmed that this process has been important for the Milky Way. Continued characterization of stars in the Milky Way’s halo will contribute to our understanding of the ancient building blocks of the Milky Way, including how many dwarf galaxies formed the Milky Way, how massive they were, and when they were accreted. Understanding the kinematics of stars is key to identifying potential birth sites and finding clumps of stars that may have formed together. This thesis presents orbital dynamics of two samples of stars: 1) chemically peculiar stars from the GALAH survey and 2) a larger sample of stars from the R-Process Alliance. Orbital velocities, energies, and integrated motions are calculated using galactic dynamics code (AGAMA). Toomre diagrams and projected-action plots visualize the orbital motions of these stars. Lindblad diagrams compare the orbital energy and angular momentum, useful for distinguishing between accreted and in-situ stars. Four stars from sample 2 have previously been identified with stellar streams. Further analysis of the remainder of sample stars is needed to establish stream member plausibility.