scholarly journals Non-spherical nucleon clusters in the mantle of a neutron star: CLDM based on Skyrme-type forces

2021 ◽  
Vol 2103 (1) ◽  
pp. 012004
Author(s):  
N A Zemlyakov ◽  
A I Chugunov ◽  
N N Shchechilin
Keyword(s):  
Neutron Star ◽  
Nuclear Matter ◽  
Liquid Drop ◽  
Outer Region ◽  
Spherical Shape ◽  
Baryon Number ◽  
Compressible Liquid ◽  
Liquid Drop Model ◽  
The Core ◽  
Nuclear Clusters

Abstract Neutron stars are superdense compact astrophysical objects. The central region of the neuron star (the core) consists of locally homogeneous nuclear matter, while in the outer region (the crust) nucleons are clustered. In the outer crust these nuclear clusters represent neutron-rich atomic nuclei and all nucleons are bound within them. Whereas in the inner crust some neutrons are unbound, but nuclear clusters still keeps generally spherical shape. Here we consider the region between the crust and the core of the star, so-called mantle, where non-spherical nuclear clusters may exist. We apply compressible liquid drop model to calculate the energy density for several shape types of nuclear clusters. It allows us to identify the most energetically favorable configuration as function of baryon number density. Employing four Skyrme-type forces (SLy4 and BSk24, BSk25, BSk26), which are widely used in the neutron star physics, we faced with strong model dependence of the ground state composition. In particular, in agreement with previous works within liquid drop model, mantle is absent for SLy4 (nuclear spheres directly transit into homogeneous nuclear matter; exotic nuclear shapes do not appear).

scholarly journals The Study of Symmetry Energy in Pasta of Neutron Star From Compressible Liquid Drop Model Approximation

2019 ◽  
Vol 2 ◽  
pp. 61-72
Author(s):  
Eko Tri Sulistyani ◽  
Rizky Ananda
Keyword(s):  
Neutron Star ◽  
Symmetry Energy ◽  
Liquid Drop ◽  
Compressible Liquid ◽  
Bonding Energy ◽  
Liquid Drop Model ◽  
Model Approximation ◽  
Protons And Neutrons ◽  
Seitz Cell ◽  
Neutron Pair

The properties of pasta which is located at the bottom of inner crust from neutron star has been studied by using compressibl e liquid drop model. Compressible liquid drop model is a modified liquid drop model as a density function. Liquid drop model based on assumption that the magnitude of nucleus bonding energy is contribution of surface, Coulomb, volume, symmetry, and proton -neutron pair effect. Pasta of neutron star behaves like liquid crystals (mesomhorpic phase). The top layer of pasta filled by free neutron gas, while in the lowest layer of the pasta is filled by proton-neutron gas. The properties of pasta are observed at temperatures close to zero Kelvin with the assumption that neutron star is on ground state and non accretion. The study of pasta emphasizes on symmetry energy’s influence. Symmetry energy reduces the magnitude of bonding energy of nucleon in the nucleus and it causes nucleon to be more easily released from nucleus. After that, symmetry energy influence the properties of pasta, such as the shape of nucleus that is non spherical (some like plates, rods, and bubbles), the fluctuative values of Wigner-Seitz cell, and uneven distribution of protons and neutrons in the pasta region of neutron star.

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 Liquid Drop Model for Nuclear Matter in the Dilute Limit

2020 ◽  
Vol 52 (2) ◽  
pp. 1980-1999
Author(s):  
Lukas Emmert ◽  
Rupert L. Frank ◽  
Tobias König
Keyword(s):  
Nuclear Matter ◽  
Liquid Drop ◽  
Liquid Drop Model ◽  
Dilute Limit

scholarly journals Neutron Star Properties: Quantifying the Effect of the Crust–Core Matching Procedure

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 220
Author(s):  
Márcio Ferreira ◽  
Constança Providência
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Strong Impact ◽  
The Core ◽  
Meta Modeling ◽  
Low Mass ◽  
Matching Procedure ◽  
The Impact

The impact of the equation of state (EoS) crust-core matching procedure on neutron star (NS) properties is analyzed within a meta-modeling approach. Using a Taylor expansion to parametrize the core equation of state (EoS) and the SLy4 crust EoS, we create two distinct EoS datasets employing two matching procedures. Each EoS describes cold NS matter in a β equilibrium that is thermodynamically stable and causal. It is shown that the crust-core matching procedure affects not only the crust-core transition but also the nuclear matter parameter space of the core EoS, and thus the most probable nuclear matter properties. An uncertainty of as much as 5% (8%) on the determination of low mass NS radii (tidal deformability) is attributed to the complete matching procedure, including the effect on core EoS. By restricting the analysis, imposing that the same set of core EoS is retained in both matching procedures, the uncertainty on the NS radius drops to 3.5% and below 1.5% for 1.9M⊙. Moreover, under these conditions, the crust-core matching procedure has a strong impact on the Love number k2, of almost 20% for 1.0M⊙ stars and 7% for 1.9M⊙ stars, but it shows a very small impact on the tidal deformability Λ, below 1%.

scholarly journals TRIPLE LAYERED COMPACT STAR WITH STRANGE QUARK MATTER

2012 ◽  
Vol 10 ◽  
pp. 123-130 ◽  
Author(s):  
KYUNGMIN KIM ◽  
HYUN KYU LEE ◽  
MANNQUE RHO
Keyword(s):  
Neutron Star ◽  
Nuclear Matter ◽  
Quark Matter ◽  
Strange Quark ◽  
Compact Star ◽  
Strange Quark Matter ◽  
Solar Mass ◽  
The Core ◽  
Triple Layer ◽  
Matter Phase

We explore the possibility of three phases in the core of neutron star in a form of triple layers. From the center, strange quark matter, kaon condensed nuclear matter and nuclear matter form a triple layer. We discuss how the phase of strange quark matter is smoothly connected to kaon condensed nuclear matter phase. We also demonstrate that the compact star with triple layered structure can be a model compatible with the 1.97-solar-mass object PSR J1614-2230 recently observed.

scholarly journals Liquid Drop Model for Investigating the Outer Crust of Neutron Star

2019 ◽  
Vol 2 ◽  
pp. 87-91
Author(s):  
Feni Fitrishia ◽  
Eko Tri Sulistyani ◽  
Romy Hanang Setya Budhi
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Total Energy ◽  
Liquid Drop ◽  
Liquid Drop Model ◽  
Model Approximation ◽  
Mass Model ◽  
System Equation ◽  
Long Time ◽  
Outer Crust

The properties of outer crust of cooling neutron star by using Liquid Drop Model approximation has been studied. Th is mass model is used to derive the properties of outer crust of neutron star matter such as total energy of system, equation of state (relationship between pressure and density), and composition of the outer crust. The properties of the outer crust are studied under the assumption that neutron star has created for long time and the matter in neutron star is in its ground state. The composition of the outer crust consists of ions Z arranged in a lattice and free electrons e, so that the total energy of the system consists of three contributions: the mass-energy of the nuclear, the energy of electrons and lattice. The equation of state (the relationship between pressure and density) shows that the pressure increases with increasing density in the outer crust layer. With a simple model based on liquid drop model, it is known that the outer crust is composed of nuclei which are at Z ≈ 20-50, with 56Fe core at the upper layer, and 154Cd core at the lowermost layer of the outer crust.

scholarly journals Structure formation in soft nanocolloids: liquid-drop model

Soft Matter ◽  
2018 ◽  
Vol 14 (16) ◽  
pp. 3063-3072 ◽  
Author(s):  
A.-K. Doukas ◽  
C. N. Likos ◽  
P. Ziherl
Keyword(s):  
Structure Formation ◽  
Polymer Brushes ◽  
Liquid Drop ◽  
Star Polymers ◽  
Compressible Liquid ◽  
Liquid Drop Model ◽  
Ordered Structures ◽  
Liquid Drops

Using a model where soft nanocolloids such as spherical polymer brushes and star polymers are viewed as compressible liquid drops, we theoretically explore interactions between such particles and the ordered structures that they form.

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