Quark Deconfinement and Implications for the Radius and the Limiting Mass of Compact Stars

Abstract

We study the consequences of the hadron-quark deconfinement phase transition\nin stellar compact objects when finite size effects between the deconfined\nquark phase and the hadronic phase are taken into account. We show that above a\nthreshold value of the central pressure (gravitational mass) a neutron star is\nmetastable to the decay (conversion) to a hybrid neutron star or to a strange\nstar. The "mean-life time" of the metastable configuration dramatically depends\non the value of the stellar central pressure. We explore the consequences of\nthe metastability of ``massive'' neutron stars and of the existence of stable\ncompact quark stars (hybrid neutron stars or strange stars) on the concept of\nlimiting mass of compact stars. We discuss the implications of our scenario on\nthe interpretation of the stellar mass and radius extracted from the spectra of\nseveral X-ray compact sources. Finally, we show that our scenario implies, as a\nnatural consequence a two step-process which is able to explain the inferred\n``delayed'' connection between supernova explosions and GRBs, giving also the\ncorrect energy to power GRBs.\n