Thesis Title: Stellar Multiplicity Statistics in APOGEE

Stellar multiplicity statistics influence and inform us on all aspects of stellar evolution.  The frequency of companions in stellar nurseries yields hints about the stellar formation process, and the multiplicity frequency of field stars also constrains the occurrences of many astrophysical transients, ranging from interacting binary systems to all Type Ia and many core collapse supernovae.  Most of my work involves the public data releases from the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), a near-IR multiplexed spectroscopic survey that is part of the Sloan Digital Sky Survey IV (SDSS-IV).  APOGEE has compiled high-resolution spectra for hundreds of thousands of stars, often with multiple visits each.  While few of these stars have enough visits to construct full orbital solutions, multiplicity statistics for the closest period systems can still be studied with as few as two visits.  Keeping the majority of the sample allows us to study multiplicity in concurrence with many other stellar properties, including spectroscopic parameters like effective temperature, surface gravity, and metallicity; astrometric ones from Gaia like galactic coordinates and distance; and parameters from isochrone fits, such as mass and age.  Using this large and well-calibrated sample, we can distinguish correlations with stellar multiplicity from mutual correlations between these parameters.

9/2019