scholarly journals Role of nucleon-nucleon correlation in transport coefficients and gravitational-wave-driven r-mode instability of neutron stars

2020 ◽  
Vol 811 ◽  
pp. 135963
Author(s):  
X.L. Shang ◽  
P. Wang ◽  
W. Zuo ◽  
J.M. Dong
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Transport Coefficients ◽  
Nucleon Nucleon ◽  
Mode Instability

scholarly journals THE R-MODE INSTABILITY IN ROTATING NEUTRON STARS

2001 ◽  
Vol 10 (04) ◽  
pp. 381-441 ◽  
Author(s):  
NILS ANDERSSON ◽  
KOSTAS D. KOKKOTAS
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Binary Systems ◽  
Current Understanding ◽  
Mode Instability ◽  
Spin Evolution ◽  
Astrophysical Significance

In this review we summarize the current understanding of the gravitational-wave driven instability associated with the so-called r-modes in rotating neutron stars. We discuss the nature of the r-modes, the detailed mechanics of the instability and its potential astrophysical significance. In particular we discuss results regarding the spin-evolution of nascent neutron stars, the detectability of r-mode gravitational waves and mechanisms limiting the spin-rate of accreting neutron stars in binary systems.

scholarly journals Neutron star seismology

2012 ◽  
Vol 8 (S291) ◽  
pp. 159-159
Author(s):  
Nils Andersson
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Wave

AbstractI will provide an overview of recent improvements in our models for vibrating neutron stars, discussing the role of composition, heat, crust elasticity and superfluidity. I will explain how the results may impact on observations, in particular related to magnetar QPOs and future gravitational-wave searches.

scholarly journals Evolution of thef-mode instability in neutron stars and gravitational wave detectability

2013 ◽  
Vol 87 (8) ◽  
Author(s):  
A. Passamonti ◽  
E. Gaertig ◽  
K. D. Kokkotas ◽  
D. Doneva
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Mode Instability

scholarly journals Transport Properties of Superfluid Phonons in Neutron Stars

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 59
Author(s):  
Cristina Manuel ◽  
Laura Tolos
Keyword(s):  
Thermal Conductivity ◽  
Neutron Stars ◽  
Transport Properties ◽  
Transport Coefficients ◽  
Effective Field ◽  
Mode Instability ◽  
Electron Collisions ◽  
Electroweak Gauge Boson ◽  
Neutrino Emissivity ◽  
The One

We review the effective field theory associated with the superfluid phonons that we use for the study of transport properties in the core of superfluid neutrons stars in their low temperature regime. We then discuss the shear and bulk viscosities together with the thermal conductivity coming from the collisions of superfluid phonons in neutron stars. With regard to shear, bulk, and thermal transport coefficients, the phonon collisional processes are obtained in terms of the equation of state and the superfluid gap. We compare the shear coefficient due to the interaction among superfluid phonons with other dominant processes in neutron stars, such as electron collisions. We also analyze the possible consequences for the r-mode instability in neutron stars. As for the bulk viscosities, we determine that phonon collisions contribute decisively to the bulk viscosities inside neutron stars. For the thermal conductivity resulting from phonon collisions, we find that it is temperature independent well below the transition temperature. We also obtain that the thermal conductivity due to superfluid phonons dominates over the one resulting from electron-muon interactions once phonons are in the hydrodynamic regime. As the phonons couple to the Z electroweak gauge boson, we estimate the associated neutrino emissivity. We also briefly comment on how the superfluid phonon interactions are modified in the presence of a gravitational field or in a moving background.

scholarly journals Phase Conversions in Neutron Stars: Implications for Stellar Stability and Gravitational Wave Astrophysics

Universe ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 493
Author(s):  
Germán Lugones ◽  
Ana Gabriela Grunfeld
Keyword(s):  
Physical Properties ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Quark Matter ◽  
Formation Mechanisms ◽  
New Class ◽  
Stellar Stability ◽  
Hybrid Stars ◽  
Stable Hybrid

We review the properties of hybrid stars with a quark matter core and a hadronic mantle, focusing on the role of key micro-physical properties such as the quark/hadron surface and curvature tensions and the conversion speed at the interface between both phases. We summarize the results of works that have determined the surface and curvature tensions from microscopic calculations. If these quantities are large enough, mixed phases are energetically suppressed and the quark core would be separated from the hadronic mantle by a sharp interface. If the conversion speed at the interface is slow, a new class of dynamically stable hybrid objects is possible. Densities tens of times larger than the nuclear saturation density can be attained at the center of these objects. We discuss possible formation mechanisms for the new class of hybrid stars and smoking guns for their observational identification.

scholarly journals Hyperons in Finite and Infinite Nuclear Systems

Universe ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 376
Author(s):  
Isaac Vidaña
Keyword(s):  
Neutron Stars ◽  
Weak Decay ◽  
Theoretical Description ◽  
Mode Instability ◽  
Decay Modes ◽  
Nuclear Systems ◽  
Γ Ray ◽  
Production Mechanisms

In this work, we shortly review the role and properties of hyperons in finite and infinite nuclear systems such as hypernuclei and neutron stars. Particularly, we describe different production mechanisms of hypernuclei, discuss some aspects of their γ-ray spectroscopy and their weak decay modes, and give a few strokes on their theoretical description. We reexamine also the role played by hyperons on the properties of neutron and proto-neutron stars with a special emphasis on the well-known “hyperon puzzle”, of which we discuss some of the solutions that have been proposed to tackle this problem. Finally, we review the role of hyperons on the cooling properties of newly born neutron stars and on the so-called r-mode instability.

scholarly journals Transport Coefficients of Hyperonic Neutron Star Cores

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 203
Author(s):  
Peter Shternin ◽  
Isaac Vidaña
Keyword(s):  
Thermal Conductivity ◽  
Neutron Star ◽  
Shear Viscosity ◽  
Transport Coefficients ◽  
Dense Matter ◽  
Baryon Number ◽  
Nucleon Nucleon ◽  
Total Thermal Conductivity ◽  
Nucleon Force ◽  
Density Region

We consider transport properties of the hypernuclear matter in neutron star cores. In particular, we calculate the thermal conductivity, the shear viscosity, and the momentum transfer rates for npΣ−Λeμ composition of dense matter in β–equilibrium for baryon number densities in the range 0.1–1 fm−3. The calculations are based on baryon interactions treated within the framework of the non-relativistic Brueckner-Hartree-Fock theory. Bare nucleon-nucleon (NN) interactions are described by the Argonne v18 phenomenological potential supplemented with the Urbana IX three-nucleon force. Nucleon-hyperon (NY) and hyperon-hyperon (YY) interactions are based on the NSC97e and NSC97a models of the Nijmegen group. We find that the baryon contribution to transport coefficients is dominated by the neutron one as in the case of neutron star cores containing only nucleons. In particular, we find that neutrons dominate the total thermal conductivity over the whole range of densities explored and that, due to the onset of Σ− which leads to the deleptonization of the neutron star core, they dominate also the shear viscosity in the high density region, in contrast with the pure nucleonic case where the lepton contribution is always the dominant one.

A RELATIVISTIC EFFECTIVE MODEL WITH PARAMETERIZED COUPLINGS FOR NEUTRON STARS: THE ROLE OF ANTIKAON CONDENSATES

2011 ◽  
Vol 20 (supp02) ◽  
pp. 133-139
Author(s):  
ALEXANDRE MESQUITA ◽  
MOISÉS RAZEIRA ◽  
DIMITER HADJIMICHEF ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
ROSANA O. GOMES ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Coupling Constants ◽  
Effective Model ◽  
Extended Model ◽  
Many Body ◽  
Parametric Dependence ◽  
Interaction Terms ◽  
Coupling Terms ◽  
Effective Models

We study the effects of antikaon condensates in neutron stars in the framework of a relativistic effective model with derivative couplings which includes genuine many-body forces simulated by nonlinear interaction terms involving scalar-isoscalar (σ, σ*), vector-isoscalar (ω, ɸ), vector-isovector (ϱ), scalar-isovector (δ) mesons. The effective model presented in this work has a philosophy quite similar to the original version of the model with parameterized couplings. But unlike that, in which the parametrization is directly inserted in the coupling constants of the Glendenning model, we present here a method for the derivation of the parametric dependence of the coupling terms, in a way that allows in one side to consistently justify this parametrization and in the other to extend in a coherent way the range of possibilities of parameterizations in effective models with derivative couplings. The extended model is then applied to the description of the mass of neutron stars.

Sign in / Sign up

Export Citation Format

Share Document