Neutron star properties from low-mass x-ray binaries

Neutron star binaries are very important astrophysical compact objects which can provide valuable information on the dense hadronic matter. In this talk, we firstly review an open question on the origin of a 2.6M⊙ compact object in GW190814. Secondly, we review our recent developments on the neutron star equations of state and compare the results with recent observations on low-mass X-ray binaries. For the comparison, we focus on the masses and radii of neutron stars. We found that the photospheres of low-mass X-ray binaries are likely to be hydrogen-poor regardless of the energy generation mechanism below and the touchdown is likely to occur away from the neutron star surface. We confirm that the upper bound of neutron star radius is consistent with that by LIGO/Virgo based on the tidal deformability of GW170817.