Evolution of Neutron Star Binding Energy in Accreting, Spinning-up Neutron Stars

Neutron star binding energy increases due to accreting matter from neighboring astronomical bodies, and decreases due to the star spinning up, increasing its angular velocity. We present a novel set of models that account for both increasing angular velocity and accreting matter to track a neutron star’s evolution. Using a rapidly rotating neutron star code we generate neutron star models for a given fixed baryon mass and angular velocity and couple it to a model of accretion-induced spin-up. We found a sharp decrease in binding energy during the first ~10 million years of certain neutron stars’ lives, which potentially changes the way that certain neutron star observational data could be interpreted.