Massive Stars: An Infrared Exploration Across the HR Diagram

Abstract

The main goal of this dissertation is to understand how stellar winds, dusty ejecta, and overall mass-loss histories affect the end-stage evolution of supergiant stars. To what extent mass loss and periods of enhanced stellar outflow can influence the terminal state of the most massive stars remains an outstanding question in the fields of stellar physics, chemical enrichment of the Galaxy, and supernova research. Here, we focus on characterizing the circumstellar (CS) ejecta around supergiants through a combination of observing techniques. Over the last several years, using the Large Binocular Telescope (LBT), MMT, NASA’s Infrared Telescope Facility (IRTF), the Very Large Telescope (VLT), and the Stratospheric Observatory for Infrared Astronomy (SOFIA), we have performed high-resolution imaging, spectroscopy, and polarimetry—methods that provide us with keen insight on mass-loss histories and the 3D morphology of the material ejected by the Local Group’s most fascinating stars.