Princeton University Extrasolar Planet Discussion Group

Binary systems in star clusters have a significant influence on their dynamical evolution. Despite the Pleiades being one of the best-known open clusters, its binary members have not received much attention since the late 1990's. Orbits for only about 20 of them are known, with periods mostly up to 3 years. I will describe a long-term spectroscopic program at the CfA to complete the census of binaries up to much longer orbital periods, and study their orbital properties, their frequencies, and the internal velocity dispersion of the cluster.