  The equation of state for quark matter is derived for a nonlocal, chiral
quark model within the mean field approximation. Special emphasis is on the
occurrence of a diquark condensate which signals a phase transition to color
superconductivity and its effects on the equation of state. We present a fit
formula for the Bag pressure, which is density dependent in case when the quark
matter is color superconducting. We calculate the quark star configurations by
solving the Tolman- Oppenheimer- Volkoff equations and demonstrate the effects
of diquark condensation on the stability of hybrid stars for different
formfactors of the quark interaction.
