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

• Published in: The Astrophysical journal Vol. 614; no. 1; pp. 314 - 325
• Main Authors: Bombaci, Ignazio, Parenti, Irene, Vidaña, Isaac
• Format: Journal Article
• Language: English
• Published: Chicago, IL IOP Publishing 10-10-2004; University of Chicago Press
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Late stages of stellar evolution (including black holes); Neutron stars; Stars; Dense matter; Neutron stars; Supernovae explosion; Metastable states; Cosmic gamma bursts; Compact stars; Quarks; Gamma ray burst; Phase transitions; Stellar mass; Quark star; Elementary particles; Strange stars; Diameter
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/423658

We study the consequences of the hadron-quark deconfinement phase transition in stellar compact objects when finitesize effects between the deconfined quark phase and the hadronic phase are taken into account. We show that above a threshold value of the central pressure (gravitational mass) a neutron star is metastable to the decay (conversion) to a hybrid neutron star or to a strange star. The mean lifetime of the metastable configuration dramatically depends on the value of the stellar central pressure. We explore the consequences of the metastability of "massive" neutron stars and of the existence of stable compact quark stars (hybrid neutron stars or strange stars) on the concept of the limiting mass of compact stars. We discuss the implications of our scenario for the interpretation of the stellar mass and radius extracted from the spectra of several X-ray compact sources. Finally, we show that our scenario implies, as a natural consequence, a two-step process that is able to explain the inferred "delayed" connection between supernova explosions and gamma-ray bursts (GRBs), giving also the correct energy to power GRBs.