Neutron star radii and crusts: uncertainties and unified equations of state
pith:2INYEROWopen to challenge →
read the original abstract
The uncertainties in neutron star (NS) radii and crust properties due to our limited knowledge of the equation of state (EOS) are quantitatively analysed. We first demonstrate the importance of a unified microscopic description for the different baryonic densities of the star. If the pressure functional is obtained matching a crust and a core EOS based on models with different properties at nuclear matter saturation, the uncertainties can be as large as $\sim 30\%$ for the crust thickness and $4\%$ for the radius. Necessary conditions for causal and thermodynamically consistent matchings between the core and the crust are formulated and their consequences examined. A large set of unified EOS for purely nucleonic matter is obtained based on 24 Skyrme interactions and 9 relativistic mean-field nuclear parametrizations. In addition, for relativistic models 17 EOS including a transition to hyperonic matter at high density are presented. All these EOS have in common the property of describing a $2\;M_\odot$ star and of being causal within stable NS. A span of $\sim 3$ km and $\sim 4$ km is obtained for the radius of, respectively, $1.0\;M_\odot$ and $2.0\;M_\odot$ star. Applying a set of nine further constraints from experiment and ab-initio calculations the uncertainty is reduced to $\sim 1$ km and $2$ km, respectively. These residual uncertainties reflect lack of constraints at large densities and insufficient information on the density dependence of the EOS near the nuclear matter saturation point. The most important parameter to be constrained is shown to be the symmetry energy slope $L$ which exhibits a linear correlation with the stellar radius, particularly for masses $\sim 1.0\;M_\odot$. Potential constraints on $L$, the NS radius and the EOS from observations of thermal states of NS are also discussed. [Abriged]
This paper has not been read by Pith yet.
Forward citations
Cited by 6 Pith papers
-
A self-consistent single-fluid framework for neutron stars admixed with mirror dark matter
Mirror dark matter admixture via mutual mean-field shifts softens the nuclear EOS, raises central densities, lowers maximum masses, and moves the direct Urca onset to higher or lower masses depending on symmetry-energ...
-
Properties of the neutron star crust informed by nuclear structure data
Bayesian NS EoS study using full nuclear posterior distributions and consistent crust modeling finds increased surface thickness and crustal moment of inertia relative to prior work.
-
The crust of dark-matter admixed neutron stars: bulk properties and torsional oscillations
Dark matter admixed neutron stars show up to 12% thinner crusts and higher torsional oscillation frequencies than pure neutron stars when dark matter forms a core, with analytical formulas matching numerics at sub-per...
-
Hyperonic equation of state for neutron stars: A systematic Bayesian comparison of density-dependent and non-linear relativistic mean-field models
Including hyperons reduces maximum neutron-star mass by 0.05-0.10 solar masses and increases radius at 1.4 solar masses by 0.5-0.8 km across all models while keeping every equation of state consistent with the 2-solar...
-
Bayesian analysis of the shear modulus in the neutron-star crust
Bayesian modeling with informed priors reduces uncertainties in neutron-star crust shear properties, predicting torsional mode frequencies of 20-50 Hz compatible with observations.
-
Hybrid stars among mass gap objects are excluded by twin stars at $1.4\,M_\odot$
Bayesian analysis of generic hybrid EOS with first-order deconfinement shows mass-gap hybrids require early transition and stiff quark matter, but data favor twins at 1.4 M_sun that exclude them.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.