Neutron star mass formula with nuclear saturation parameters for asymmetric nuclear matter

Low-mass neutron stars are directly associated with the nuclear saturation parameters because their central density is definitely low. We have already found a suitable combination of for expressing star mass and gravitational redshift, i.e., $\ensuremath{\eta}\ensuremath{\equiv}({K}_{0}{L}^{2}{)}^{1/3}$ incompressibility symmetric matter, ${K}_{0}$, density-dependent symmetry energy, $L$. In this study, we newly find another given by ${\ensuremath{\eta}}_{\ensuremath{\tau}}\ensuremath{\equiv}(\ensuremath{-}{K}_{\ensuremath{\tau}}{L}^{5}{)}^{1/6}$ isospin dependence asymmetric ${K}_{\ensuremath{\tau}}$, derive empirical relations redshift as function ${\ensuremath{\eta}}_{\ensuremath{\tau}}$ normalized number density. With these relations, one can evaluate star, whose less than threefold density, within $\ensuremath{\sim}10%$ accuracy, radius few percent accuracy. addition, discuss constraints from terrestrial experiments, using together those astronomical observations. Furthermore, tight correlation between $\ensuremath{\eta}$. correlation, constraint on ${K}_{\ensuremath{\tau}}$ $\ensuremath{-}348\ensuremath{\le}{K}_{\ensuremath{\tau}}\ensuremath{\le}\ensuremath{-}237\text{ }\text{ }\mathrm{MeV}$, assuming that $L=60\ifmmode\pm\else\textpm\fi{}20$ ${K}_{0}=240\ifmmode\pm\else\textpm\fi{}20\text{ }\mathrm{MeV}$.