  The possible existence of two families of compact stars, neutron stars and
quark stars, naturally leads to a scenario in which a conversion process
between the two stellar objects occurs with a consequent release of energy of
the order of $10^{53}$ erg. We discuss recent hydrodynamical simulations of the
burning process and neutrino diffusion simulations of cooling of a newly formed
strange star. We also briefly discuss this scenario in connection with recent
measurements of masses and radii of compact stars.
