Characterizing the Population of Binary Stars from Eclipsing Binaries Observed by the Kepler Mission

Open Access
- Author:
- Wells, Mark
- Graduate Program:
- Astronomy and Astrophysics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- May 31, 2024
- Committee Members:
- Andrej Prsa, Special Member
Stephane Coutu, Outside Unit & Field Member
Eric Feigelson, Major Field Member
Eric Ford, Chair, Minor Member & Dissertation Advisor
Hyungsuk Tak, Major Field Member
Randy McEntaffer, Professor in Charge/Director of Graduate Studies - Keywords:
- binary stars
Kepler
eclipsing binaries
binary populations
stochastic approximation
inverse modeling - Abstract:
- Modeling binary star populations is critical to linking the theories of star formation and stellar evolution with observations. To test such theories, accurate models of binary star populations are needed. Survey missions provide large samples of eclipsing binaries that can be used to infer properties about the underlying binary population such as the distribution of orbital periods, eccentricities and stellar mass ratios. In particular, the Kepler Eclipsing Binary Catalog (KEBC), with its estimated > 90% completeness, provides a reliable observational constraint. In this work, a sample of eclipsing binary stars from the KEBC was used to establish a binary population model capable of reproducing the observed occurrence rates of binary stars in our Galaxy. Samples of eclipsing binary stars were simulated from a binary population model and compared to the KEBC. The difference between the simulated and observed eclipsing binary period distribution was used to update the period distribution of the binary population model. The resulting period distribution is consistent with volume-limited surveys that incorporate multiple sources of data such as radial velocity measurements and direct imaging. To analyze the effect model assumptions had on the results, the modeling process was repeated using multiple fixed choices for the intrinsic distributions of orbital eccentricities and stellar mass ratios. The input distribution that governed the ratio of a binary system’s component stellar masses was found to have no significant impact on the resulting period distribution. However, the choice of eccentricity distribution did result in varying amounts of attenuation in the resulting period distribution. This work also demonstrates how a binary population’s joint distribution of period and eccentricity can be inferred using measures of period and eclipse timings. The timings between eclipses were measured for the KEBC and can be used to fit the joint period-eccentricity distribution of the binary population. This work shows how binary populations can be constrained using only information contained within light curve data. These methods, developed for the KEBC, can be readily generalized to light curve data from ongoing and future surveys such as those from the Transiting Exoplanet Survey Satellite and the Vera C. Rubin Observatory.