Neutron Stars and Massive Quark Matter

Using the Color-Dielectric model to describe quark confinement, including strange quarks and accounting for beta--equilibrium, we get masses for a static neutron star in the range $1.3\leq M/M_{\odot}\leq 1.54 $ for a radius $R\approx 9$ km. Rapid cooling through the direct URCA mechanism is obtained. The implications for the composition of neutron stars is discussed.