Determining the Masses and Radii of Heartbeat Stars
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Date
2024-05
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The Ohio State University
Abstract
Heartbeat stars (HBs) are a rare subclass of eclipsing binary (EB) variable-type stars, with only a couple hundred identified. There is still much to learn from further analysis of these systems, like determining the masses and radii. HBs are a perfect candidate for this study because EB stars are the most effective way to measure precise masses and radii. They are also short-period high-eccentricity systems, allowing for easy investigation into how stars evolve differently in short-period binary orbits. Determining the mass and radius of both stars in the system allows further investigation into how tides affect the interior stellar structure. HBs are easily identifiable due to the structure of their phase-folded light curve (LC), as it resembles an EKG or heartbeat. This LC structure is caused by the stars in the system passing each other so closely that tidal distortion causes the stars to have a non-spherical shape. This stretching in an ellipsoidal structure spikes their brightness and creates the namesake heartbeat shape of the LC. Less than five HBs systems have been analyzed in detail and our goal is to more than triple this number using fifteen HBs identified from the five thousand binary star systems in the Gaia Double-line Spectroscopic Binaries catalog. Transiting Exoplanet Survey Satellite (TESS) LCs allows us to determine the orbital eccentricity, inclination, and period of the binary. With an accurate model, I use Gaia’s radial velocity (RV) data to constrain the masses and radii using the Physics of Eclipsing Binaries (PHOEBE) modeling package. This project began in the Summer of 2023, when I completed the analysis for one HB system. Since then, I have refined the pipeline and applied this process to work toward masses and radii for the other fourteen HBs. With the results of this project, I aim to create an accessible catalog of short-period and high-eccentricity HBs systems used in furthering general binary star science.
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Keywords
Heartbeat, Star, Mass, Radius, Binary, Astronomy