The neutron star in Cassiopeia A: equation of state, superfluidity, and Joule heating

Understand

The thermomagnetic evolution of the young neutron star in Cassiopea A is studied by considering fast neutrino emission processes.

• In particular, we consider neutron star models obtained from the equation of state computed in the framework of the Brueckner-Bethe-Goldstone many-body theory and variational methods, and models obtained with the Akmal-Pandharipande-Ravenhall equation of state.
• It is shown that it is possible to explain a fast cooling regime as the one observed in the neutron star in Cassiopea A if the Joule heating produced by dissipation of the small-scale magnetic field in the crust is taken into account.
• We thus argue that it is difficult to put severe constraints on the superfluid gap if the Joule heating is considered.