scholarly journals Role of the symmetry energy on the structure of neutron stars with unified equations of state

2019 ◽  
Author(s):  
Nicolas Chamel ◽  
John Michael Pearson ◽  
Alexander Y. Potekhin ◽  
Anthea F. Fantina ◽  
Camille Ducoin ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Symmetry Energy ◽  
Equations Of State

scholarly journals Erratum: Unified equations of state for cold non-accreting neutron stars with Brussels-Montreal functionals. I. Role of symmetry energy

2019 ◽  
Vol 486 (1) ◽  
pp. 768-768 ◽  
Author(s):  
J M Pearson ◽  
N Chamel ◽  
A Y Potekhin ◽  
A F Fantina ◽  
C Ducoin ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Symmetry Energy ◽  
Equations Of State

scholarly journals QUARK–DIQUARK EQUATIONS OF STATE MODELS: THE ROLE OF INTERACTIONS

2003 ◽  
Vol 12 (03) ◽  
pp. 519-526 ◽  
Author(s):  
J. E. HORVATH ◽  
G. LUGONES ◽  
J. A. DE FREITAS PACHECO
Keyword(s):  
Equation Of State ◽  
Boundary Conditions ◽  
Neutron Stars ◽  
Hard Sphere ◽  
Degrees Of Freedom ◽  
Equations Of State ◽  
Compact Star ◽  
Star Models ◽  
State Models

Recent observational data suggests a high compacticity (the quotient M/R) of some "neutron" stars. Motivated by these works we revisit models based on quark–diquark degrees of freedom and address the question of whether that matter is stable against diquark disassembling and hadronization within the different models. We find that equations of state modeled as effective λϕ4 theories do not generally produce stable self-bound matter and are not suitable for constructing very compact star models, that is the matter would decay into neutron matter. We also discuss some insights obtained by including hard sphere terms in the equation of state to model repulsive interactions. We finally compare the resulting equations of state with previous models and emphasize the role of the boundary conditions at the surface of compact self-bound stars, features of a possible normal crust of the latter and related topics.

scholarly journals Nuclear symmetry energy effects on neutron stars properties

2020 ◽  
Vol 15 ◽  
pp. 128
Author(s):  
Ch. C. Moustakidis ◽  
V. P. Psonis ◽  
S. E. Massen
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Systematic Study ◽  
Symmetry Energy ◽  
Potential Model ◽  
Equations Of State ◽  
Baryon Density ◽  
Nuclear Symmetry Energy ◽  
Global Properties ◽  
Potential Part

We construct a class of nuclear equations of state based on a schematic potential model, that originates from the work of Prakash et. al. [1], which reproduce the results of most microscopic calculations. The equations of state are used as input for solving the Tolman- Oppenheimer-Volkov equations for corresponding neutron stars. The potential part contribution of the symmetry energy to the total energy is parameterized in a generalized form both for low and high values of the baryon density. The obtained nuclear equations of state are applied for the systematic study of the global properties of a neutron star (masses, radii and composition). We also address on the problem of the existence of correlation between the pressure near the saturation density and the radius.

scholarly journals Nuclear equation of state constraints from tidal deformability of neutron stars

2019 ◽  
Vol 21 ◽  
pp. 44
Author(s):  
Ch. C. Moustakidis
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Symmetry Energy ◽  
State Constraints ◽  
Equations Of State ◽  
Recent Observation ◽  
Nuclear Symmetry Energy ◽  
Nuclear Equation Of State ◽  
Theoretical Predictions

We study the effect of nuclear equation of state on the tidal polarizability of neutron stars. The predicted equations of state for the β-stable nuclear matter are parameterized by varying the slope L of the symmetry energy at saturation density on the interval 65 MeV≤L≤115 MeV. The effects of the density dependence of the nuclear symmetry energy on the neutron star tidal polarizability are presented and analyzed. A comparison of theoretical predictions with the recent observation predictions is also performed and analyzed.

scholarly journals Neutron stars and supernova explosions in the framework of Landau's theory

2015 ◽  
Vol 24 (07) ◽  
pp. 1550059 ◽  
Author(s):  
Hua Zheng ◽  
Jaime Sahagun ◽  
Aldo Bonasera
Keyword(s):  
Neutron Stars ◽  
Symmetry Energy ◽  
Equations Of State ◽  
Gluon Plasma ◽  
Instability Region ◽  
High Density ◽  
Many Body ◽  
Body Interaction ◽  
Protons And Neutrons ◽  
Supernova Explosions

In this paper, a general formula of the symmetry energy for many-body interaction is proposed and the commonly used two-body interaction symmetry energy is recovered. Within Landau's theory (Lt), we generalize two equations of state (EoS) CCSδ3 and CCSδ5 to asymmetric nuclear matter. We assume that the density and density difference between protons and neutrons divided by their sum are order parameters. We use different EoS to study neutron stars by solving the TOV equations. We demonstrate that different EoS give different mass and radius relation for neutron stars even when they have exactly the same ground state (gs) properties (E/A, ρ0, K, S, L and K sym ). Furthermore, for one EoS we change K sym and fix all the other gs parameters. We find that for some K sym the EoS becomes unstable at high density even for neutron matter. This suggests that a neutron star (NS) can exist below and above the instability region but in different states: a quark gluon plasma (QGP) at high density and baryonic matter at low density. If the star's central density is in the instability region, then we associate these conditions to the occurrence of supernovae (SN).

scholarly journals Role of the symmetry energy on the neutron-drip transition in accreting and nonaccreting neutron stars

2016 ◽  
Vol 93 (1) ◽  
Author(s):  
A. F. Fantina ◽  
N. Chamel ◽  
Y. D. Mutafchieva ◽  
Zh. K. Stoyanov ◽  
L. M. Mihailov ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Symmetry Energy

scholarly journals NUCLEAR SYMMETRY ENERGY EFFECTS ON NEUTRON STARS PROPERTIES

2007 ◽  
Vol 22 (17) ◽  
pp. 1233-1253 ◽  
Author(s):  
V. P. PSONIS ◽  
CH. C. MOUSTAKIDIS ◽  
S. E. MASSEN
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Symmetry Energy ◽  
Linear Relation ◽  
Equations Of State ◽  
Baryon Density ◽  
Saturation Density ◽  
Global Properties ◽  
Dense Nuclear Matter ◽  
Potential Part

We construct a class of nuclear equations of state based on a schematic potential model, that originates from the work of Prakash et al.,1 which reproduce the results of most microscopic calculations. The equations of state are used as input for solving the Tolman–Oppenheimer–Volkov equations for the corresponding neutron stars. The potential part contribution of the symmetry energy to the total energy is parametrized in a generalized form both for low and high values of the baryon density. Special attention is devoted to the construction of the symmetry energy in order to reproduce the results of most microscopic calculations of dense nuclear matter. The obtained nuclear equations of state are applied for the systematic study of the global properties of a neutron star (masses, radii and composition). The calculated masses and radii of the neutron stars are plotted as a function of the potential part parameters of the symmetry energy. A linear relation between these parameters, the radius and the maximum mass of the neutron star is obtained. In addition, a linear relation between the radius and the derivative of the symmetry energy near the saturation density is found. We also address the problem of the existence of correlation between the pressure near the saturation density and the radius.

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