HD 172189, a Cluster Member Binary System with a δ Scuti Component in the Field of View of COROT

Photometric and spectroscopic results for the star HD172189, member of the open cluster IC 4756 in the summer field of the space mission COROT, are presented. From photometric observations in the Stromgren system carried out at various epochs, its binary nature as well as the presence of a δ Scuti-type pulsating component have been discovered. The frequency analysis of the whole dataset con- firms a dominant frequency of 19.5974 c d−1 with a maximum amplitude near 0.02 mag plus other frequencies in the range 18–20 c d−1. A preliminary orbital solution from the light curve and from four FEROS spectra reveals two similar components of around 1.5 M ⊙ orbiting with a period of 5.702 d.