We analyze the full Kepler phase curve of KOI-964 , a binary system consisting of a hot white dwarf on an eclipsing orbit around an A-type host star .
Using all 18 quarters of long-cadence photometry , we carry out a joint light curve fit and obtain improved phase curve amplitudes , occultation depths , orbital parameters , and transit ephemeris over the previous results of \citet carter2011 .
A periodogram of the residuals from the phase curve fit reveals an additional stellar variability signal from the host star with a characteristic period of 0.620276 \pm 0.000011 days and a full amplitude of 24 \pm 2 ppm .
We also present new Keck/HIRES radial velocity observations which we use to measure the orbit and obtain a mass ratio of q = 0.106 \pm 0.012 .
Combining this measurement with the results of a stellar isochrone analysis , we find that the masses of the host star and white dwarf companion are 2.23 \pm 0.12 M _ { \Sun } and 0.236 ^ { +0.028 } _ { -0.027 } M _ { \Sun } , respectively .
The effective temperatures of the two components are 9940 ^ { +260 } _ { -230 } K and 15080 \pm 400 K , respectively , and we determine the age of the system to be 0.21 ^ { +0.11 } _ { -0.08 } Gyr .
We use the measured system properties to compute predicted phase curve amplitudes and find that while the measured Doppler boosting and mutual illumination components agree well with theory , the ellipsoidal distortion amplitude is significantly underestimated .
We detail possible explanations for this discrepancy , including interactions between the dynamical tide of the host star and the tidal bulge and possible non-synchronous rotation of the host star .