The properties of hybrid stars in a low symmetry energy model

In this work, we investigate the properties of hybrid stars based on the Togashi EoS with a low value for the symmetry energy. We adopt the Togashi EoS and (2+1)− flavor NJL EoS to describe the hadron matter and quark matter, respectively, and construct the hybrid star with the 3-window interpolation approach. The structure of the hybrid star satisfies the observational constraints well, and its mass–radius relation is similar to that of the pure neutron star for the Togashi EoS which the maximum mass exceeds 2 times of solar mass and the radius is small due to a low symmetry energy. It is consistent with the current constraints on the mass–radius from the observational data. We also study the cooling simulation of neutron stars in this paper. Comparing the cooling curves with observations, our investigation shows that the cooling curves of hybrid stars are compatible with most of the pulsar ′ s data.