Rigidly Rotating Strange Quark Star

The possibility of the existence of quark matter dates back to early seventies. Bodmer remarked that matter consisting of deconfined up, down and strange quarks could be the absolute ground state of matter at zero pressure and temperature. If this is true then objects made of such matter, so-called ”strange star”, could exist. There are several proposed mechanisms for formation of quark stars. Quark stars are expected to form during the collapse of the core a massive star after supernova explosion as a result of a first or second order phase transition, resulting in deconfined quark matter. In the region where the temperature is low and the density is high enough that hadrons are crushed into quark matter, there is a whole family of color superconducting phases. Color superconducting quark matter may well occur naturally in the universe, in the cold dense cores of compact (neutron) stars. So, the proto-neutron star core or the neutron star core is a favorable environment for the conversion of ordinary matter to strange quark matter. Another possibility for strange star formation is that some neutron star in low-mass X-ray binaries can accrete sufficient mass to undergo a phase transition to become a strange star. Such