Quark matter symmetry energy and quark stars. (arXiv:1212.1388v1 [astro-ph.SR])

Quark matter symmetry energy and quark stars. (arXiv:1212.1388v1 [astro-ph.SR]):
We extend the confined-density-dependent-mass model to include isospin
dependence of the equivalent quark mass. Within the
confined-isospin-density-dependent-mass model, we study the quark matter
symmetry energy, the stability of strange quark matter, and the properties of
quark stars. We find that including isospin dependence of the equivalent quark
mass can significantly enhance the quark matter symmetry energy and stiffen
strange quark matter. The recently discovered large mass pulsar PSR J1614-2230
with a mass of $1.97\pm0.04M_{\odot}$ can be well described by a quark star if
the equivalent quark mass is strongly isospin dependent, indicating that the
quark matter symmetry energy might be much stronger than the nuclear matter
symmetry energy.