Finding White Dwarfs with Transit Searches

Abstract

We make predictions for the rate of discovery of eclipsing white dwarf-main sequence (WD-MS) binaries in terrestrial-planet transit searches, taking the planned Kepler and Eddington missions as examples. We use a population synthesis model to characterize the Galactic WD-MS population, and we find that, despite increased noise due to stellar variability compared with the typical planetary case, discovery of >100 non-accreting, eclipsing WD-MS systems is likely using Kepler and Eddington, with periods of 2-20 days and transit amplitudes of |delta m|~0.0003-0.00003 magnitudes. Follow-up observations of these systems could accurately test the theoretical white dwarf mass-radius relation or theories of binary star evolution.