Constraining the Formation History of the Galactic Disk and Halo Systems through Kinematic Studies of Metal-Poor Stars

Doctoral Dissertation

Abstract

The analyses presented in this work all fall under the umbrella term “Galactic archaeology”, the sub-field of astronomy dedicated to reconstructing the assembly and chemical-evolution history of the Galaxy. The following chapters chart a journey through the Milky Way, from the disk system to the stellar halo and the outskirts of the Galaxy, identifying stellar chemo-dynamical patterns that may shed light on the complex mechanisms involved in forming these components. In particular, I use metal-poor stars, and their close associates, carbon-enhanced metal-poor (CEMP) stars, throughout my analyses as tracer populations (or stellar “fossils”) to map features of interest. In the thick-disk, I identify two unusual CEMP populations, and describe their potential implications for the history of the disk system, potentially supporting a separable metal-weak thick-disk (MWTD) component. In the halo, I compare two CEMP-based methods for verifying the inner- and outer-halo separation, and cover the recent changes to our understanding of the halo following the release of high-precision astrometry from the Gaia satellite. At the outskirts of the halo, I present evidence of an asymmetric metallicity gradient within this region, and discuss its implications for the complex accretion history of the outer-halo component.

Attributes

Attribute NameValues
Author Sarah E. Dietz
Contributor Vinicius M. Placco, Research Director
Contributor Timothy C. Beers, Research Director
Contributor Peter Garnavich, Committee Member
Contributor Malgorzata Dobrowolska, Committee Member
Contributor J. Christopher Howk, Committee Member
Degree Level Doctoral Dissertation
Degree Discipline Physics
Degree Name Doctor of Philosophy
Banner Code
  • PHD-PHYS

Defense Date
  • 2020-07-07

Submission Date 2020-12-07
Subject
  • Astronomy

  • Astrophysics

  • CEMP Stars

  • Stellar Kinematics

  • Physics

  • Metal-Poor Stars

  • Milky Way Galaxy

Record Visibility Public
Content License
Departments and Units
Catalog Record

Files

Please Note: You may encounter a delay before a download begins. Large or infrequently accessed files can take several minutes to retrieve from our archival storage system.