Understanding Interacting Binary Stars Identified in Astronomical Surveys

University Of Washington, Seattle WA

Investigators

Abstract

This project is aimed at understanding how stars that are formed in binary pairs are distributed throughout our galaxy and how they evolve in time by interacting with each other. The team members will use telescope time available through their university to accomplish follow-up observations of variable objects that are identified in several current ongoing sky surveys. The results will reveal the number and nature of these systems that can be compared to theoretical evolution models to understand their evolution. This study also serves as preparation for the future Large Synoptic Survey Telescope (the NSF funded astronomy project recommended by the United States' 2010 Decadal Survey), by revealing the types of variables that will be found. The intellectual merit of the results include new understanding of how mass transfer between stars affects their evolution, how common these stars are at various locations in the galaxy, how magnetic fields enter into the evolution, and how variable the objects are at different evolution stages. The project has broad impact through building up and working with an international community of scientists that will know how to maximize results from the future Synoptic Telescope, including undergraduate students in STEM fields as well as graduate and postdoctoral students in astronomy. The investigators will use Apache Point Observatory to obtain spectra, radial velocities, and high time-resolution light curves of cataclysmic variables from ongoing sky surveys (Sloan, Catalina, Kepler, and Palomar) in order to further the understanding of the evolution of interacting close binary stars. The results will determine the galactic distribution, test population models, and the purity of the instability strip for accreting white dwarfs, parameterize the population containing magnetic white dwarfs, as well as reveal the number and nature of variables that will be present in the future Large Synoptic Survey Telescope (LSST). The new results include number densities out of the galactic plane, physical parameters of the variables at the shortest orbital periods, angular momentum losses, heating and cooling resulting from accretion changes, as well as the numbers containing magnetic white dwarfs. A broader impact of these results is the buildup of an international community of astronomers, including undergraduate STEM students, graduate students and postdocs that will be able to exploit the LSST by identifying and following up close binaries of interest.