Kepler photometry of KIC 10661783: a binary star with total eclipses and δ Scuti pulsations

Abstract

We present Kepler satellite photometry of KIC 10661783, a short-period binary\nstar system which shows total eclipses and multi-periodic delta Scuti\npulsations. A frequency analysis of the eclipse-subtracted light curve reveals\nat least 68 frequencies of which 55 or more can be attributed to pulsation\nmodes. The main limitation on this analysis is the frequency resolution within\nthe 27-day short-cadence light curve. Most of the variability signal lies in\nthe frequency range 18 to 31 c/d, with amplitudes between 0.1 and 4 mmag. One\nharmonic term (2.f) and a few combination frequencies (f_i+f_j) have been\ndetected. From a plot of the residuals versus orbital phase we assign the\npulsations to the primary star in the system. The pulsations were removed from\nthe short-cadence data and the light curve was modelled using the\nWilson-Devinney code. We are unable to get a perfect fit due to the residual\neffects of pulsations and also to the treatment of reflection and reprocessing\nin the light curve model. A model where the secondary star fills its Roche lobe\nis favoured, which means that KIC 10661783 can be classified as an oEA system.\nFurther photometric and spectroscopic observations will allow the masses and\nradii of the two stars to be measured to high precision and hundreds of delta\nScuti pulsation frequencies to be resolved. This could lead to unique\nconstraints on theoretical models of delta Scuti stars, if the evolutionary\nhistory of KIC 10661783 can be accounted for.\n