The age of the Hyades is about 625 million years. The cluster core, where stars are most densely packed, has a radius of 2.7 parsecs (corresponding to a diameter of 17.6 light years), and the cluster's tidal radius is 10 parsecs (corresponding to a diameter of 65 light years). About one-third of confirmed member stars have been observed well outside this boundary, in the cluster's extended halo. These stars are probably in the process of escaping from its gravitational influence.