Detailed Characterization of Heartbeat Stars and their Tidally Excited Oscillations

Heartbeat stars are a class of eccentric binary stars with short-period orbits and characteristic "heartbeat" signals in their light curves, especially at orbital periastron where strong tidal interactions occur. In many heartbeat stars, tidally excited oscillations cause the star to pulsate throughout its orbit, with pulsation frequencies at exact integer multiples of the orbital frequency. Here, we characterize the tidally excited oscillations in the heartbeat stars KIC 6117415, KIC 11494130, and KIC 5790807. Using Kepler light curves and radial velocity data, we first model the heartbeat stars using the binary modeling software ELLC, including gravity darkening, limb darkening, and reflection. We conduct a frequency analysis to identify the magnitude and frequency of tidally excited oscillations. We then compare our results with tidal theories to determine whether chance resonances can be responsible for the observed tidally excited oscillations. We conclude with an investigation of whether resonance locking between tidal forcing and stellar oscillation modes can explain any prominent tidally excited oscillations.