matter in extreme conditions

What the nose shows: Black Widow systems and the fundamental nature of nuclear matter

Apr 22, 2021
Neutron stars are made of highly compressed material called degenerate matter, which is so dense it must be described using the laws of quantum mechanics. As a result, NSs should have a unique relationship between mass and radius, determined by an “equation of state” (EoS). An EoS is a thermodynamic description of the entwined properties of, for example, temperature, pressure, and volume. The steam in a pressure cooker can be described by an EoS; so can the interior of a star. For neutron star-like conditions only density matters, which results in a density-dependent EoS, P(rho). But because their material is in an exotic state not found anywhere on Earth, the EoS for neutron stars remains unknown.