Things That Were, Things That Are, and Some Things That Have Not Yet Come To Pass: Investigations in Galactic Archaeology via Asteroseismology, Spectroscopy, and Astrometry of Evolved Stars to Unlock the Secrets of the Milky Way in the Past, Present, and Future

Abstract

Stellar Galactic Archaeology is the study of the stars in the Milky Way as artifacts to determine the formation and evolution of our home Galaxy. With a rapid increase in space-borne telescopes and ground-based counterparts that can collect considerable amounts of precise data, we can perform Galactic Archaeology for enormous selections of evolved stars through the multiple methods of asteroseismology, spectroscopy, and astrometry. Using the APO-K2 sample of ~7,500 stars, precision values are calculated and used to investigate various stellar parameter spaces for the sample, including the evolutionary states of the stars, the galactic kinematic profiles, and the identification of halo and stream stars. A well-understood selection function is determined to consider the APO-K2 sample on a Galactic scale. Further investigations include shedding light on a possible cause of overestimated asteroseismic masses in low-metallicity halo stars and the effect of Galactic chemical evolution on the future creation and habitability of planets in the Milky Way, based on their assumed ability to form plate tectonics with the elements available from their host stars. Also included is an in-depth investigation specific to the asteroseismic parameters of Milky Way stars. The investigation involves the observation of a sample of Kepler stars in search of binary companions, which may inhibit our observations of asteroseismic oscillations in Kepler light curves by introducing spurious flux. Of the two investigations performed in this vein, amplitude dilution, or the reduction of observable asteroseismic oscillations, is found to at least in part be caused by stellar companions. However, it is not the only cause of non-detections in sample stars. As an extension of this work, the script designed to determine secondary star contamination in large Kepler and TESS data samples underwent a redesign to create a web tool for students, allowing them to access space telescope data.