 With the exception of its white dwarfs, the cluster's central contain only star systems of at least .This tight concentration of heavy stars gives the Hyades its overall structure, with a core defined by bright, closely packed systems and a halo consisting of more widely separated stars in which later spectral types are common.The core radius is 2.7 parsecs (8.8 light-years, a little more than the distance between the Sun and Sirius), while the half-mass radius, within which half the cluster's mass is contained, is .