A mean-field calculation of the equation of state of supernova matter

The equation of state for hot dense matter occurring in stellar collapse is calculated using the Hartree-Fock approximation at finite temperature. The effective nucleon-nucleon interaction is a modified Skyrme force which gives a rather good value of the compression modulus in nuclear matter. Results are presented for the adiabat S = 1 per baryon, with a fixed value of the electron fraction Y_e = 0.25, in the density range ρ = 0.02 to 0.07 baryons per fm³. We find that nuclei are still present in the medium. As a consequence the adiabatic index is slightly less than 4/3. We also discuss the presence of a transition, around half nuclear matter density, towards a phase made of bubbles.

Laboratoire associé au CNRS.