Abstract. We use an effective quark model to describe both hadronic matter and deconfined quark matter. By calculating the equations of state and the corresponding neutron star properties, we show that the internal properties of the nucleon have important implications for the properties of these systems.

We investigate the equations of state for pure neutron matter and for nonstrange and strange hadronic matter in β equilibrium, including , , and hyperons. The masses and radii of these kinds of stars are obtained. For a pure neutron star, the maximum mass is about 1.8M sun , while for a strange (nonstrange) hadronic star in β equilibrium, the maximum mass is around 1.45M sun (1.7M sun ). The typical radii of pure neutron stars and strange hadronic stars are about 11.5-13.0 km and 11.5-12.5 km, respectively.

We investigate the phase diagram of isospin asymmetric matter at T=0 in the two flavor Nambu-Jona-Lasinio model. Our approach describes the single nucleon as a confined quark-diquark state, the saturation properties of nuclear matter at normal densities, and the phase transition to normal or color superconducting quark matter at higher densities. The resulting equation of state of charge neutral matter and the structure of compact stars are discussed.