Complete understanding of neutron-star cooling

Establish a complete understanding of neutron-star cooling, including how the composition and equation of state of matter at supranuclear densities determine the thermal evolution of neutron stars.

Background

The paper studies neutron-star cooling as a probe of dense-matter composition and the equation of state. It focuses specifically on the possible appearance of Delta baryons and the additional direct-Urca neutrino-emission channels that they enable.

The authors present Delta direct-Urca emissivities and incorporate them into neutron-star cooling simulations, finding that these processes can substantially accelerate cooling. Nevertheless, the paper frames the broader physical understanding of neutron-star cooling, particularly in relation to the uncertain composition and equation of state of supranuclear matter, as unresolved.