  In this paper we discuss the QCD phase-transitions in the nontopological
soliton model of quark confinement and explore possible astrophysical
consequences. Our key idea is to look at quark stars (which are believed to
exist since the quark matter is energetically preferred over the ordinary
matter) from the point of view of soliton model. We propose that the phase
transition taking place during the core collapse of massive evolved star may
provide a new physical effect not taken into account in modeling the supernova
explosions. We also point out the possibility that merging quark stars may
produce gamma-ray bursts energetic enough to be at cosmological distances. Our
idea based on the finite-temperature nontopologiocal soliton model overcomes
major difficulties present in neutron star merger scenario --- the baryon
loading problem and nonthermal spectra of the bursts.
