HD?51106 and HD?50747: an ellipsoidal binary and a triple system observed with CoRoT

Context. We present an analysis of the observations of HD?51106 and HD?50747 by the satellite CoRoT, obtained during its initial run, and of the spectroscopic preparatory observations.Aims. We complete an analysis of the light curve, extract the main frequencies observed, and discuss some preliminary interpretations about the stars.Methods. We used standard Fourier transform and pre-whitening methods to extract information about the periodicities of the stars.Results. HD 51106 is an ellipsoidal binary, the light curve of which can be completely explained by the tidal deformation of the star and smaller secondary effects. HD?50747 is a triple system containing a variable star, which exhibits many modes of oscillation with periods in the range of a few hours. On the basis of this period range and the analysis of the physical parameters of the star, we conclude that HD?50747 is a ?-Doradus star.