scholarly journals Role of crustal physics in the tidal deformation of a neutron star

2019 ◽  
Vol 100 (4) ◽  
Author(s):  
Bhaskar Biswas ◽  
Rana Nandi ◽  
Prasanta Char ◽  
Sukanta Bose
Keyword(s):  
Neutron Star ◽  
Tidal Deformation

scholarly journals A Superfluid Perspective on Neutron Star Dynamics

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 17
Author(s):  
Nils Andersson
Keyword(s):  
Neutron Star ◽  
Degrees Of Freedom ◽  
Temperature Scale ◽  
Fluid System ◽  
Fluid Core ◽  
State Of Matter ◽  
Entrainment Effect ◽  
Neutron Component ◽  
The Impact

As mature neutron stars are cold (on the relevant temperature scale), one has to carefully consider the state of matter in their interior. The outer kilometre or so is expected to freeze to form an elastic crust of increasingly neutron-rich nuclei, coexisting with a superfluid neutron component, while the star’s fluid core contains a mixed superfluid/superconductor. The dynamics of the star depend heavily on the parameters associated with the different phases. The presence of superfluidity brings new degrees of freedom—in essence we are dealing with a complex multi-fluid system—and additional features: bulk rotation is supported by a dense array of quantised vortices, which introduce dissipation via mutual friction, and the motion of the superfluid is affected by the so-called entrainment effect. This brief survey provides an introduction to—along with a commentary on our current understanding of—these dynamical aspects, paying particular attention to the role of entrainment, and outlines the impact of superfluidity on neutron-star seismology.

scholarly journals A shallow water analogue of asymmetric core-collapse, and neutron star kick/spin

2011 ◽  
Vol 7 (S279) ◽  
pp. 134-137
Author(s):  
Thierry Foglizzo ◽  
Frédéric Masset ◽  
Jérôme Guilet ◽  
Gilles Durand
Keyword(s):  
Neutron Star ◽  
Shallow Water ◽  
Acoustic Waves ◽  
Large Scale ◽  
Massive Stars ◽  
Core Collapse ◽  
Hydraulic Jumps ◽  
Core Collapse Supernova ◽  
Accretion Shock

AbstractMassive stars end their life with the gravitational collapse of their core and the formation of a neutron star. Their explosion as a supernova depends on the revival of a spherical accretion shock, located in the inner 200km and stalled during a few hundred milliseconds. Numerical simulations suggest that the large scale asymmetry of the neutrino-driven explosion is induced by a hydrodynamical instability named SASI. Its non radial character is able to influence the kick and the spin of the resulting neutron star. The SWASI experiment is a simple shallow water analog of SASI, where the role of acoustic waves and shocks is played by surface waves and hydraulic jumps. Distances in the experiment are scaled down by a factor one million, and time is slower by a factor one hundred. This experiment is designed to illustrate the asymmetric nature of core-collapse supernova.

scholarly journals The role of fission on neutron star mergers and its impact on the r-process peaks

2016 ◽  
Author(s):  
M. Eichler ◽  
A. Arcones ◽  
A. Kelic ◽  
O. Korobkin ◽  
K. Langanke ◽  
...  
Keyword(s):  
Neutron Star ◽  
R Process

scholarly journals Black hole and neutron star mergers in galactic nuclei: the role of triples

2019 ◽  
Vol 488 (2) ◽  
pp. 2825-2835 ◽  
Author(s):  
Giacomo Fragione ◽  
Nathan W C Leigh ◽  
Rosalba Perna
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
Massive Stars ◽  
Star Clusters ◽  
Galactic Nuclei ◽  
Compact Objects ◽  
Large Numbers ◽  
Binary Case

ABSTRACT Nuclear star clusters that surround supermassive black holes (SMBHs) in galactic nuclei are thought to contain large numbers of black holes (BHs) and neutron stars (NSs), a fraction of which form binaries and could merge by Kozai–Lidov oscillations (KL). Triple compact objects are likely to be present, given what is known about the multiplicity of massive stars, whose life ends either as an NS or a BH. In this paper, we present a new possible scenario for merging BHs and NSs in galactic nuclei. We study the evolution of a triple black hole (BH) or neutron star (NS) system orbiting an SMBH in a galactic nucleus by means of direct high-precision N-body simulations, including post-Newtonian terms. We find that the four-body dynamical interactions can increase the KL angle window for mergers compared to the binary case and make BH and NS binaries merge on shorter time-scales. We show that the merger fraction can be up to ∼5–8 times higher for triples than for binaries. Therefore, even if the triple fraction is only ∼10–$20\rm{\,per\,cent}$ of the binary fraction, they could contribute to the merger events observed by LIGO/VIRGO in comparable numbers.

scholarly journals Thermonuclear Burning in the Envelope of an Accreting Neutron Star

1980 ◽  
Vol 88 ◽  
pp. 329-334 ◽  
Author(s):  
E. Ergma ◽  
T. Tutukov
Keyword(s):  
Neutron Star ◽  
Analytical Method ◽  
Main Sequence ◽  
Radiative Cooling ◽  
Hydrogen Burning ◽  
Heating Source ◽  
Thermonuclear Burning ◽  
Evolutionary Scenario ◽  
Low Mass

A simple analytical method has been used to investigate thermonuclear flashes in a degenerate envelope of an accreting neutron star. The heating source is the compression of envelope and the cooling is due to the radiative cooling of the envelope. The role of hydrogen burning is discussed. A possible evolutionary scenario for formation of preburster binaries consisting of a neutron star and a low mass main sequence star is proposed.

scholarly journals Comparison between the Thomas–Fermi and Hartree–Fock–Bogoliubov Methods in the Inner Crust of a Neutron Star: The Role of Pairing Correlations

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 206
Author(s):  
Matthew Shelley ◽  
Alessandro Pastore
Keyword(s):  
Neutron Star ◽  
Mean Field ◽  
Pairing Correlation ◽  
Field Methods ◽  
Density Region ◽  
Thomas Fermi ◽  
Hartree Fock ◽  
Pairing Correlations ◽  
Mean Field Methods

We investigated the role of a pairing correlation in the chemical composition of the inner crust of a neutron star with the extended Thomas–Fermi method, using the Strutinsky integral correction. We compare our results with the fully self-consistent Hartree–Fock–Bogoliubov approach, showing that the resulting discrepancy, apart from the very low density region, is compatible with the typical accuracy we can achieve with standard mean-field methods.

scholarly journals The Role of Opacities in Accretion Disks

1995 ◽  
Vol 10 ◽  
pp. 597-598
Author(s):  
R. Wehrse
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Potential Energy ◽  
Accretion Disk ◽  
Accretion Disks ◽  
Heat Generation ◽  
White Dwarf ◽  
Young Stellar Object ◽  
Central Object

An accretion disk is formed when matter with angular momentum is flowing on a gravitating object (as e.g. a white dwarf, a neutron star, a young stellar object, or a black bole). It radiates because the transport of angular momentum (required for the matter to reach the central object) necessarily implies the conversion of potential energy into a form of energy that corresponds to higher entropy. Many aspects of the physics (as e.g. the mechanism for the heat generation) are not yet well understood but they are presently one of the centers of astronomical interest (see e.g. the books by Frank, King, and Raine, 1992, or by Wheeler, 1993).

scholarly journals Role of strangeness to the neutron star mass and cooling

2018 ◽  
Vol 168 ◽  
pp. 04011
Author(s):  
Chang-Hwan Lee ◽  
Yeunhwan Lim ◽  
Chang Ho Hyun ◽  
Kyujin Kwak
Keyword(s):  
Neutron Star ◽  
Dense Matter ◽  
High Density ◽  
Saturation Density ◽  
Strange Quarks ◽  
Star Mass ◽  
Neutron Star Mass ◽  
Neutron Star Cooling

Neutron star provides unique environments for the investigation of the physics of extreme dense matter beyond normal nuclear saturation density. In such high density environments, hadrons with strange quarks are expected to play very important role in stabilizing the system. Kaons and hyperons are the lowest mass states with strangeness among meson and bayron families, respectively. In this work, we investigate the role of kaons and hyperons to the neutron star mass, and discuss their role in the neutron star cooling.

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