  We investigate the properties of the static neutron stars and
strangeness-mixed stars, based on the equations of state derived from a pion
mean-field approach. Using the empirical data on the pion-nucleus scattering
and bulk properties of nuclear matter, we have already fixed all the parameters
in a previous work, where the nucleons and hyperons were shown to be modified
in various nuclear medium. In the current work, we first examine the energy and
pressure inside a neutron star. We show that the central densities in various
neutron stars vary within the range of $(3-6)\rho_0$, where $\rho_0$ is the
normal nuclear matter density. The mass-radius relations are obtained and
discussed. As the slope parameter for neutron matter increases, the radii of
the neutron stars increase with their masses fixed. We also study the
strangeness-mixed stars or the hyperon stars using the same sets of the
parameters. As the strangeness content of strange matter increases, the binding
energy per nucleon is saturated and the corresponding equation of state becomes
softened. Consequently, the central densities of the strangeness-mixed stars
increase. Assuming that recently observed neutron stars are the
strangeness-mixed ones, we find that the central densities increase. In the
case of the pure strange stars, the central densities reach almost
$(5-6)\rho_0$.
