To what extent mass loss and periods of enhanced stellar outflow can influence the terminal state of the most massive stars remains an open question in the fields of stellar physics, chemical enrichment of the Local Universe, and supernova research. For my dissertation, I focus on characterizing the stellar ejecta around supergiants through a combination of observing techniques. Using the LBT, MMT, IRTF, VLT, and SOFIA observatories, I have performed high-resolution imaging, spectroscopy, and polarimetry—methods that provide us with keen insight on mass-loss histories and 3D morphology of the Local Groups most fascinating stars. For Galactic red supergiants (RSGs), we are able to observe the gas and CS dust ejecta both close in to the central star and at larger distances. When combined with radiative-transfer models, this infrared imaging provides evidence for both variable/high mass-loss events and constant mass loss over the last few thousand years.
Massive Stars--An Exploration Across the HR Diagram
University of Minnesota