scholarly journals Neutron star structure with nuclear force mediated by hypothetical X17 boson

2021 ◽  
Vol 252 ◽  
pp. 04008
Author(s):  
Vlasios Petousis ◽  
Martin Veselský ◽  
Jozef Leja
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Force ◽  
Nuclear Equation Of State ◽  
Upper Limit ◽  
Merger Event ◽  
Star Structure

A reported 17 MeV boson, which has been proposed as an explanation to the 8Be and 4He anomaly, is investigated in the context of its possible influence to neutron stars structure. Implementing a mX =17 MeV to the nuclear equation of state using different incompressibility values K0=245 MeV and K0=260 MeV and solving Tolman-Oppenheimer-Volkoff equations, we estimate an upper limit of MTOV ≈ 2.4M⊙ for a non rotating neutron star with span in radius R between 11.5 km to 14 km. Moving away from pure -NN with admixture of 10% protons and simulating possible softening of equation of state due to hyperons, we see that our estimated limits fit quite well inside the newest reported studies, coming from neutron stars merger event, GW190814

scholarly journals Nuclear equation of state and neutron star cooling

2017 ◽  
Vol 26 (04) ◽  
pp. 1750015 ◽  
Author(s):  
Yeunhwan Lim ◽  
Chang Ho Hyun ◽  
Chang-Hwan Lee
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Thermal Evolution ◽  
Observation Data ◽  
Nuclear Equation Of State ◽  
The Core ◽  
Dense Nuclear Matter ◽  
Nuclear Models

In this paper, we investigate the cooling of neutron stars with relativistic and nonrelativistic models of dense nuclear matter. We focus on the effects of uncertainties originated from the nuclear models, the composition of elements in the envelope region, and the formation of superfluidity in the core and the crust of neutron stars. Discovery of [Formula: see text] neutron stars PSR J1614−2230 and PSR J0343[Formula: see text]0432 has triggered the revival of stiff nuclear equation of state at high densities. In the meantime, observation of a neutron star in Cassiopeia A for more than 10 years has provided us with very accurate data for the thermal evolution of neutron stars. Both mass and temperature of neutron stars depend critically on the equation of state of nuclear matter, so we first search for nuclear models that satisfy the constraints from mass and temperature simultaneously within a reasonable range. With selected models, we explore the effects of element composition in the envelope region, and the existence of superfluidity in the core and the crust of neutron stars. Due to uncertainty in the composition of particles in the envelope region, we obtain a range of cooling curves that can cover substantial region of observation data.

scholarly journals Rotation-Driven Phase Transitions in the Cores of Pulsars

2017 ◽  
Vol 45 ◽  
pp. 1760035
Author(s):  
Richard D. Mellinger ◽  
William Spinella ◽  
Fridolin Weber ◽  
Gustavo A. Contrera ◽  
Milva Orsaria
Keyword(s):  
Phase Transitions ◽  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Quark Matter ◽  
Nuclear Data ◽  
Particle Composition ◽  
Nuclear Equation Of State ◽  
The Impact ◽  
Gravitational Compression

In this paper, we discuss the impact of rotation on the particle composition of rotating neutron stars (pulsars). Particular emphasis is put on the formation of quark matter during stellar spin-down, driven by continuous gravitational compression. Our study is based on modern models for the nuclear equation of state whose parameters are tightly constrained by nuclear data, neutron star masses, and the latest estimates of neutron star radii.

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 Cooling of hybrid neutron stars with microscopic equations of state

2020 ◽  
Vol 498 (1) ◽  
pp. 344-354 ◽  
Author(s):  
J-B Wei ◽  
G F Burgio ◽  
H-J Schulze ◽  
D Zappalà
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Equations Of State ◽  
P Wave ◽  
Cooling Curves ◽  
Hartree Fock ◽  
Nuclear Equation Of State ◽  
Neutron Star Cooling ◽  
Quark Models

ABSTRACT We model the cooling of hybrid neutron stars combining a microscopic nuclear equation of state in the Brueckner–Hartree–Fock approach with different quark models. We then analyse the neutron star cooling curves predicted by the different models and single out the preferred ones. We find that the possibility of neutron p-wave pairing can be excluded in our scenario.

scholarly journals Speed of sound and quark confinement inside neutron stars

2020 ◽  
Vol 229 (22-23) ◽  
pp. 3651-3661
Author(s):  
Michał Marczenko
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Speed Of Sound ◽  
Dense Matter ◽  
High Mass ◽  
Quark Confinement ◽  
Binary Neutron Star ◽  
Upper Limit ◽  
Unified Description

AbstractSeveral observations of high-mass neutron stars (NSs), as well as the first historic detection of the binary neutron star merger GW170817, have delivered stringent constraints on the equation of state (EoS) of cold and dense matter. Recent studies suggest that, in order to simultaneously accommodate a 2M⊙ NS and the upper limit on the compactness, the pressure has to swiftly increase with density and the corresponding speed of sound likely exceeds the conformal limit. In this work, we employ a unified description of hadron-quark matter, the hybrid quark-meson-nucleon (QMN) model, to investigate the EoS under NS conditions. We show that the dynamical confining mechanism of the model plays an important role in explaining the observed properties of NSs.

scholarly journals Nuclear Pairing Gaps and Neutron Star Cooling

Universe ◽  
2020 ◽  
Vol 6 (8) ◽  
pp. 115
Author(s):  
Jin-Biao Wei ◽  
Fiorella Burgio ◽  
Hans-Josef Schulze
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Star Mass ◽  
Hartree Fock ◽  
Mass Distributions ◽  
Nuclear Equation Of State ◽  
Neutron Star Mass ◽  
Neutron Star Cooling ◽  
Proton Pairing

We study the cooling of isolated neutron stars with particular regard to the importance of nuclear pairing gaps. A microscopic nuclear equation of state derived in the Brueckner-Hartree-Fock approach is used together with compatible neutron and proton pairing gaps. We then study the effect of modifying the gaps on the final deduced neutron star mass distributions. We find that a consistent description of all current cooling data can be achieved and a reasonable neutron star mass distribution can be predicted employing the (slightly reduced by about 40%) proton 1S0 Bardeen-Cooper-Schrieffer (BCS) gaps and no neutron 3P2 pairing.

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