New model of neutron stars predicts supernova-like explosions

Ars Technica : Neutron stars are the collapsed cores of stars at least eight times as massive as the Sun. The centers of the stars are believed to be primarily composed of neutrons, while a roughly kilometer-thick “crust” of heavy nuclei appears to cover their surface. The current model for neutron star behavior assumes the crust is stratified by the atomic mass of the nuclei. It also assumes the crust has a temperature of absolute zero because the combination of high density and pressure creates quantum effects similar to those that occur at low temperatures. To evaluate the validity of those assumptions, an international team of astronomers developed a model that uses more realistic physical conditions: It reduces the stratification and assumes a higher temperature. This model predicts that the crust would be separated into three layers, one of which releases a very high number of neutrinos. Those neutrinos would carry away large amounts of energy from the star in a process common in Type Ia supernova explosions, but not predicted by the standard model of neutron stars. The x-ray bursts associated with the process are distinct enough that observations could verify whether the new model is a more accurate depiction of neutron stars.