The effects of the equation of state and the composition on the thermal evolution of neutron stars

Abstract

Even though the neutron stars have been studied for over six decades there is little consensus over the mechanisms involved in their thermal evolution. Similarly, despite decades of study, the behavior of exotic particles, especially under highly degenerate situations, garner little consensus in academia. We combined these two fields in the study of observational data in an attempt to identify involvement of specific exotic particles in neutron star thermal evolution. We generated various equations of state (EOS) that lie within the theoretically established limits for the pion condensates and hyperons, and attempted to find thermal evolution regimens that are consistent with observations that cannot be explained by standard neutron star cooling models. Our chosen observations are; the Cassiopeia-A (Cas-A) supernova remnant for our pion model, and various low mass X-ray binaries (LMXB) for our hyperon and pion models. Our results strongly suggest the involvement of these aforementioned exotic particles in thermal evolution and related problems of certain neutron stars that lead to their unusual thermal behavior.