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