RUI: Understanding the cores of horizontal branch stars via MESA, Gaia, and asteroseismology

This project seeks to deepen our understanding of horizontal branch (HB) stars, a vital phase in stellar evolution that helps us learn about the life cycles of stars like our Sun. By studying these stars, specifically subdwarf B (sdB) stars, this work will improve our models of stellar physics, focusing on the structure and internal processes that govern their evolution. This project will provide significant educational opportunities, involving undergraduate and graduate students in hands-on research. The research team will also incorporate this work into their extensive outreach programs. The primary goal of this project is to apply observations and advanced modeling techniques to probe the internal structure of horizontal branch stars, focusing on sdB stars. These stars offer a unique opportunity to study the cores of stars that do not undergo helium fusion in the same way as other stars on the horizontal branch. Using data from the Gaia, TESS, and Kepler missions, the team will measure key properties --such as distances, radii, and masses -- for over 2,000 sdB stars. These measurements will be combined with spectral energy distribution fitting and asteroseismic data to refine our understanding of stellar models. 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.