https://doi.org/10.1140/epja/i2016-16058-5
Review
Quark matter nucleation in neutron stars and astrophysical implications
1
Dipartimento di Fisica “E. Fermi”, Università di Pisa, Largo B. Pontecorvo, 3, I-56127, Pisa, Italy
2
INFN, Largo B. Pontecorvo, 3, I-56127, Pisa, Italy
3
European Gravitational Observatory, Via E. Amaldi, I-56021, Cascina, Italy
4
CFisUC, Department of Physics, University of Coimbra, PT-3004-516, Coimbra, Portugal
* e-mail: ignazio.bombaci@unipi.it
Received:
2
October
2015
Accepted:
14
December
2015
Published online:
18
March
2016
A phase of strong interacting matter with deconfined quarks is expected in the core of massive neutron stars. We investigate the quark deconfinement phase transition in cold ( and hot
-stable hadronic matter. Assuming a first order phase transition, we calculate and compare the nucleation rate and the nucleation time due to quantum and thermal nucleation mechanisms. We show that above a threshold value of the central pressure a pure hadronic star (HS) (i.e. a compact star with no fraction of deconfined quark matter) is metastable to the conversion to a quark star (QS) (i.e. a hybrid star or a strange star). This process liberates an enormous amount of energy, of the order of 1053erg, which causes a powerful neutrino burst, likely accompanied by intense gravitational waves emission, and possibly by a second delayed (with respect to the supernova explosion forming the HS) explosion which could be the energy source of a powerful gamma-ray burst (GRB). This stellar conversion process populates the QS branch of compact stars, thus one has in the Universe two coexisting families of compact stars: pure hadronic stars and quark stars. We introduce the concept of critical mass
for cold HSs and proto-hadronic stars (PHSs), and the concept of limiting conversion temperature for PHSs. We show that PHSs with a mass
could survive the early stages of their evolution without decaying to QSs. Finally, we discuss the possible evolutionary paths of proto-hadronic stars.
© SIF, Springer-Verlag Berlin Heidelberg, 2016