Physics & Astronomy ETDs
Publication Date
Summer 7-28-2026
Abstract
Asymptotic giant branch (AGB) stars are among the final evolutionary stages of low- and intermediate-mass stars and among the most luminous cool stellar populations in the Milky Way (MW). Their strong infrared emission allows them to be observed through regions of high interstellar extinction, making them useful tracers of the inner MW. However, their use is limited by unreliable distances because many are dust-obscured and variable, while geometric parallaxes are often unavailable or uncertain. This thesis develops statistical distance-estimation methods for large samples of oxygen-rich AGB stars. The resulting distances broadly agree with literature estimates, supporting their statistical reliability for large AGB populations. These distances place AGB stars in a three-dimensional Galactic context and enable studies of Galactic structure through their spatial distributions, luminosities, variability, and population differences across the MW. In addition, this thesis applies machine learning to distance estimation and stellar classification, demonstrating its usefulness for separating stellar populations in large surveys. Overall, this work develops methods and catalogs that expand the use of AGB stars as Galactic tracers and provide distances for samples at least an order of magnitude larger than those accessible through traditional geometric techniques in the MW
Degree Name
Physics
Level of Degree
Doctoral
Department Name
Physics & Astronomy
First Committee Member (Chair)
Dr. Ylva Pihlstrom
Second Committee Member
Dr. Loránt Sjouwerman
Third Committee Member
Dr. Gregory Taylor
Fourth Committee Member
Prof. dr. Huib Jan van Langevelde
Language
English
Keywords
Milky Way, AGB, Galactic structure, Machine Learning, Stellar populations
Document Type
Dissertation
Recommended Citation
Bhattacharya, Rajorshi. "New Distance Distributions of Asymptotic Giant Branch Stars and Their Role in Tracing Galactic Structure." (2026). https://digitalrepository.unm.edu/phyc_etds/372