SUPER DENSE STARS. “In neutron stars, the degeneracy pressure produced by the neutrons counterbalances the gravitational pull to keep the star in a hydrostatic equilibrium state. The structure of neutron stars with less dense core provides an opportunity to transform into quark stars. The densest compact objects composed of up, down and strange quark matter are named as quark stars.”
https://www.sciencedirect.com/science/article/pii/S0577907319309773