scholarly journals Neutron Star Cooling Within the Equation of State With Induced Surface Tension

Particles ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 693-704
Author(s):  
Stefanos Tsiopelas ◽  
Violetta Sagun
Keyword(s):  
Surface Tension ◽  
Equation Of State ◽  
Neutron Stars ◽  
Thermal Evolution ◽  
Compact Object ◽  
Light Elements ◽  
Cassiopeia A ◽  
Neutron Star Cooling ◽  
Model Features ◽  
Good Agreement

We study the thermal evolution of neutron stars described within the equation of state with induced surface tension (IST) that reproduces properties of normal nuclear matter, fulfills the proton flow constraint, provides a high-quality description of hadron multiplicities created during the nuclear-nuclear collision experiments, and it is equally compatible with the constraints from astrophysical observations and the GW170817 event. The model features strong direct Urca processes for the stars above 1.91M⊙. The IST equation of state shows very good agreement with the available cooling data, even without introducing nuclear pairing. We also analysed the effect of the singlet proton/neutron and triplet neutron pairing on the cooling of neutron stars of different mass. We show that the description of the compact object in the center of the Cassiopeia A does not necessarily require an inclusion of neutron superfluidity and/or proton superconductivity. Our results indicate that data of Cassiopeia A can be adequately well reproduced by a 1.66M⊙ star with an atmosphere of light elements. Moreover, the IST EoS reproduces each of the observational datasets for the surface temperature of Cassiopeia A either by a rapidly cooling ∼1.955M⊙ star with paired and unpaired matter or by a 1.91M⊙ star with the inclusion of neutron and proton pairings in the singlet channel.

scholarly journals Possibility of rapid neutron star cooling with a realistic equation of state

2019 ◽  
Vol 2019 (11) ◽  
Author(s):  
Akira Dohi ◽  
Ken’ichiro Nakazato ◽  
Masa-aki Hashimoto ◽  
Matsuo Yasuhide ◽  
Tsuneo Noda
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Symmetry Energy ◽  
Surface Composition ◽  
Thermal Evolution ◽  
Small Radius ◽  
Neutron Star Cooling ◽  
Fast Cooling ◽  
Urca Process

Abstract Whether fast cooling processes occur or not is crucial for the thermal evolution of neutron stars. In particular, the threshold of the direct Urca process, which is one of the fast cooling processes, is determined by the interior proton fraction $Y_p$, or the nuclear symmetry energy. Since recent observations indicate the small radius of neutron stars, a low value is preferred for the symmetry energy. In this study, simulations of neutron star cooling are performed adopting three models for the equation of state (EoS): Togashi, Shen, and LS220 EoSs. The Togashi EoS has been recently constructed with realistic nuclear potentials under finite temperature, and found to account for the small radius of neutron stars. As a result, we find that, since the direct Urca process is forbidden, the neutron star cooling is slow with use of the Togashi EoS. This is because the symmetry energy of Togashi EoS is lower than those of other EoSs. Hence, in order to account for observed age and surface temperature of isolated neutron stars with the use of the Togashi EoS, other fast cooling processes are needed regardless of the surface composition.

scholarly journals Testing Pulsar Thermal Evolution Theories with Observation

2004 ◽  
Vol 218 ◽  
pp. 21-28
Author(s):  
Sachiko Tsuruta
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Thermal Evolution ◽  
Dense Matter ◽  
Stellar Radius ◽  
Neutron Star Cooling ◽  
Successful Launch ◽  
Careful Comparison ◽  
Insight Into

With the successful launch of Chandra and XMM-Newton, the time has arrived when careful comparison of thermal evolution theories of isolated neutron stars with observations will offer a better hope for distinguishing among various competing neutron star cooling theories. For instance, the latest theoretical and observational developments may already exclude both nucleon and kaon direct Urea cooling. In this way we can now have a realistic hope for determining various important properties, such as the composition, superfluidity, the equation of state and stellar radius. These developments should help us obtain deeper insight into the properties of dense matter.

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 The Induced Surface Tension Contribution for the Equation of State of Neutron Stars

2019 ◽  
Vol 871 (2) ◽  
pp. 157 ◽  
Author(s):  
Violetta V. Sagun ◽  
Ilídio Lopes ◽  
Aleksei I. Ivanytskyi
Keyword(s):  
Surface Tension ◽  
Equation Of State ◽  
Neutron Stars

scholarly journals Double dark matter admixed neutron star

2018 ◽  
Vol 27 (16) ◽  
pp. 1950002 ◽  
Author(s):  
Zeinab Rezaei
Keyword(s):  
Dark Matter ◽  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Equations Of State ◽  
Compact Object ◽  
Gravitational Redshift ◽  
Two Fluid

The dark matter (DM) in neutron stars can exist from the lifetime of the progenitor or when captured by this compact object. The properties of DM that enter the neutron stars through each step could be different from each other. Here, we investigate the structure of neutron stars which are influenced by the DM in two processes. Applying a generalization of two-fluid formalism to three-fluid one and the equation-of-state from the rotational curves of galaxies, we explore the structure of double DM admixed neutron stars. The behavior of the neutron and DM portions for these stars is considered. In addition, the influence of the DM equations of state on the stars with different contributions of visible and DM are studied. The gravitational redshift of these stars in different cases of DM equations of state is investigated.

scholarly journals Neutron Stars: A Novel Equation of State with Induced Surface Tension

2017 ◽  
Vol 850 (1) ◽  
pp. 75 ◽  
Author(s):  
Violetta V. Sagun ◽  
Ilídio Lopes
Keyword(s):  
Surface Tension ◽  
Equation Of State ◽  
Neutron Stars

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 Magnetic neutron star cooling and microphysics

2018 ◽  
Vol 609 ◽  
pp. A74 ◽  
Author(s):  
A. Y. Potekhin ◽  
G. Chabrier
Keyword(s):  
Neutron Star ◽  
Finite Difference ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Thermodynamic Functions ◽  
Thermal Evolution ◽  
Relative Importance ◽  
Quasistationary Approximation ◽  
Theoretical Predictions ◽  
Neutron Star Cooling

Aims. We study the relative importance of several recent updates of microphysics input to the neutron star cooling theory and the effects brought about by superstrong magnetic fields of magnetars, including the effects of the Landau quantization in their crusts. Methods. We use a finite-difference code for simulation of neutron-star thermal evolution on timescales from hours to megayears with an updated microphysics input. The consideration of short timescales (≲1 yr) is made possible by a treatment of the heat-blanketing envelope without the quasistationary approximation inherent to its treatment in traditional neutron-star cooling codes. For the strongly magnetized neutron stars, we take into account the effects of Landau quantization on thermodynamic functions and thermal conductivities. We simulate cooling of ordinary neutron stars and magnetars with non-accreted and accreted crusts and compare the results with observations. Results. Suppression of radiative and conductive opacities in strongly quantizing magnetic fields and formation of a condensed radiating surface substantially enhance the photon luminosity at early ages, making the life of magnetars brighter but shorter. These effects together with the effect of strong proton superfluidity, which slows down the cooling of kiloyear-aged neutron stars, can explain thermal luminosities of about a half of magnetars without invoking heating mechanisms. Observed thermal luminosities of other magnetars are still higher than theoretical predictions, which implies heating, but the effects of quantizing magnetic fields and baryon superfluidity help to reduce the discrepancy.

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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