Quark deconfinement transition in hyperonic matter

We discuss the properties of the hadron-quark mixed phase in compact stars using a realistic equation of state of hyperonic matter and the MIT bag model. We find that the equation of state of the mixed phase is similar to that given by the Maxwell construction, but that the mixed phase becomes mechanically unstable if the surface tension of the interface between the two pure phases is strong enough. The composition of the mixed phase is very different from that of the Maxwell construction; in particular, hyperons are completely suppressed.