Neutron Star Properties with Hyperons
  In the light of the recent discovery of a neutron star with a mass accurately determined to be almost two solar masses, it has been suggested that hyperons cannot play a role in the equation of state of dense matter in $\beta$-equilibrium. We re-examine this issue in the most recent development of the quark-meson coupling model. Within a relativistic Hartree-Fock approach and including the full tensor structure at the vector-meson-baryon vertices, we find that not only must hyperons appear in matter at the densities relevant to such a massive star but that the maximum mass predicted is completely consistent with the observation. 
D.L. Whittenbury, J.D. Carroll, A.W. Thomas, K. Tsushima and J.R.   Stone
nucl-th astro-ph.HE hep-ph