Constraints on the Dense-Matter Equation of State
Neutron stars hold matter at densities beyond that of an atomic nucleus, and how this matter behaves, its equation of state, is one of the big open questions in nuclear physics. Their cooling offers a way in: how quickly a young neutron star cools depends on what its core is made of. Re-analysing X-ray observations of isolated neutron stars, we found three young stars that are far too cold for their age to be explained by standard cooling. Comparing them with a large set of magneto-thermal simulations, we showed that only equations of state that allow fast neutrino cooling can reproduce them. Many current models do not, which makes these cold stars some of the strongest observational constraints on dense matter to date.
Related publications
A. Marino*, C. Dehman*, K. Kovlakas*, N. Rea* et al., Constraints on the dense matter equation of state from young and cold isolated neutron stars, Nature Astronomy 8, 1020–1030 (these authors contributed equally to this work), 2024. PDF | arXiv | DOI
F. Anzuini, A. Melatos, C. Dehman et al., Thermal luminosity degeneracy of magnetized neutron stars with and without hyperon cores, MNRAS 515, 3014, 2022. PDF | arXiv | DOI
F. Anzuini, A. Melatos, C. Dehman et al., Fast cooling and internal heating in hyperon stars, MNRAS 509, 2609, 2022. PDF | arXiv | DOI