NSF Award
2206814
A natural and very common product of star formation processes, binary stars provide a vital foundation of stellar studies as calibrators for stellar sizes, masses, temperatures, and luminosities. They also serve as probes for stellar structure, formation and evolution, tidal interactions, and other more specialized fields such as accretion physics, asteroseismology, resonant dynamics, and the formation and evolution of exoplanets in multiple star systems. Eclipsing binaries are a special group of binary stars, in which the two stars periodically eclipse each other, producing variations in their light curves. A team of scientists at the SETI institute and at San Diego State University will perform an analysis of deviations from the regular, periodic behavior in this special type of binary stars. Deviations can be introduced by the presence of planets and by rotation and tidal forces. By investigating these deviations, the team will be able to constrain the internal structure of each component star, providing unique constraints to improve current stellar structure models. In addition, the team will create a set of 3-days workshops for STEM teachers, in collaboration with existing national education outreach programs that partner astronomers with teachers in grades 3 to 9. The workshops will provide hands-on project-based learning with an overarching theme of eclipses and transits. <br/><br/>The project plan has three components: 1) Measure decades-long period changes for hundreds of eclipsing binaries; 2) Constrain the internal structure of each star in suitable binaries; 3) Probe for the presence of additional bodies (stars, circumbinary planets). The investigators will use all available photometric data from ground- and space-based archives for hundreds of known eclipsing binaries. Furthermore, they will use a state-of-the-art modeling code that predicts the measured eclipse times based on the orbital configuration of the particular system and the properties of its components, as well as on the corresponding tidal and general relativity effects. Presently, period changes in certain binaries are used to measure the average apsidal motion constant of the binary. This project has the potential to measure the apsidal motion constants of each star in a much larger sample. This will be made possible by using eclipse times measured over many decades. This is critical because the precession timescales are much longer than the orbital period of the binaries and, as a result, their detection often requires photometric observations spanning decades. Studying a large sample of eclipsing binaries covering different stellar types and environments will also advance the knowledge of the physics of binary interactions, leading to a better understanding of tidal forces, migration, spin-orbit coupling, and mass transfer.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
