316 research outputs found
Simplified Thermal Evolution of Proto-hybrid Stars
We study the possibility of a hadron-quark phase transition in the interior
of neutron stars, taking into account different schematic evolutionary stages
at finite temperature. Furthermore, we analyze the astrophysical properties of
hot and cold hybrid stars, considering the constraint on maximum mass given by
the pulsars J1614-2230 and J1614-2230. We obtain cold hybrid stars with maximum
masses M. Our study also suggest that during the
proto-hybrid star evolution a late phase transition between hadronic matter and
quark matter could occur, in contrast with previous studies of proto-neutron
stars.Comment: 4 pages, 2 figures, contribution to the Proceedings of the VII
International Workshop on Astronomy and Relativistic Astrophysics - IWARA
201
Constant entropy hybrid stars: a first approximation of cooling evolution
We aim to study the possibility of a hadron-quark phase transition in the
interior of neutron stars, taking into account different schematic evolutionary
stages at finite temperature. We also discuss the strange quark matter
stability in the quark matter phase. Furthermore, we aim to analyze the
astrophysical properties of hot and cold hybrid stars, considering the
constraint on maximum mass given by the pulsars J1614-2230 and J0348+0432. We
have developed a computational code to construct semi-analytical hybrid
equations of state at fixed entropy per baryon and to obtain different families
of hybrid stars. An analytical approximation of the Field Correlator Method is
developed for the quark matter equation of state. For the hadronic equation of
state we use a table based on the relativistic mean field theory, without
hyperons. We solved the relativistic structure equations of hydrostatic
equilibrium and mass conservation for hybrid star configurations. For the
different equations of state obtained, we calculated the stability window for
the strange quark matter, lepton abundances, temperature profiles and contours
profiles for the maximum mass star depending on the parameters of the Field
Correlator Method. We also computed the mass-radius and gravitational
mass-baryonic mass relationships for different hybrid star families. We have
analyzed different stages of hot hybrid stars as a first approximation of the
cooling evolution of neutron stars with quark matter cores. We obtain cold
hybrid stars with maximum masses for different combinations of
the Field Correlator Method parameters. In addition, our study based on the
gravitational mass - baryonic mass plane shows a late phase transition between
hadronic and quark matter during the proto-hybrid star evolution, in contrast
with previous studies of proto-neutron stars.Comment: 12 pages, 14 figures, published in A&A 601, A21 (2017
On Inflation and Variation of the Strong Coupling Constant
Variation of constants in the very early universe can generate inflation. We
consider a scenario where the strong coupling constant was changing in time and
where the gluon condensate underwent a phase transition ending the inflation.Comment: 12 pages, 1 figure, accepted for publication in International Journal
of Modern Physics
Time variation of fundamental constants: two phenomenological models
Time variation of fundamental constants, a strong signal of new physics, is
analyzed comparing extant data with two phenomenological models. Results are
discussed.Comment: 8 pages, 1 figure. aipproc.sty; Talk given in the X Mexican School of
Particles and Fields, Playa del Carmen, Mexico, 2002
Tecamebas bentónicas intersticiales de las playas de Pinamar (Buenos Aires, Argentina)
Fil: Vucetich, MarÃa Cristina. CONICETFil: Escalante, Alicia H.. CONICE
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