  We study the scenario that a new born strange quark star cools to the Quantum
ChromoDynamics (QCD) phase transition temperature and converts to a neutron
star, and we calculate the evolution of temperature and luminosity of the
compact star. We argue that the conversion energy released can be of the order
$10^{53}$ erg. We also propose that a second neutrino burst will be emitted at
the completion of this phase transition.
