  Using several relativistic mean field models (such as GM1, GM3, NL3, TM1,
FSUGold and IU-FSU) as well as the quark-meson coupling model, we calculate the
particle fractions, the equation of state, the maximum mass and radius of a
neutron star within relativistic Hartree approximation. In determining the
couplings of the isoscalar, vector mesons to the octet baryons, we examine the
extension of SU(6) spin-flavor symmetry to SU(3) flavor symmetry. Furthermore,
we consider the strange ($\sigma^{\ast}$ and $\phi$) mesons, and study how they
affect the equation of state. We find that the equation of state in SU(3)
symmetry can sustain a neutron star with mass of $(1.8 \sim 2.1) M_{\odot}$
even if hyperons exist inside the core. In addition, the strange vector
($\phi$) meson and the variation of baryon structure in matter also play
important roles in supporting a massive neutron star.
