prof. dr hab. David Blaschke (IFT) at 10:00!

The difference between the energy per nucleon in pure neutron matter and in symmetric nuclear matter (SNM) is called the (a)symmetry energy. It plays a key role when relating the equation of state in SNM as probed, e.g., in heavy-ion collisions, with the one that govern the structure and composition of neutron stars. We prove that the symmetry energy contribution to the neutron star equation of state (beta- equilibrium and charge neutrality) is a universal function of the density for densities above saturation, provided that the direct Urca cooling process is inhibited. Phenomenology of compact star cooling supports the fulfilment of this constraint.