scholarly journals COMPUTATION OF NEUTRON STAR STRUCTURE USING MODERN EQUATION OF STATE

2006 ◽  
Vol 21 (07) ◽  
pp. 1555-1565 ◽  
Author(s):  
G. H. BORDBAR ◽  
M. HAYATI
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Equations Of State ◽  
Maximum Mass ◽  
Neutron Star Matter ◽  
Radio Pulsars ◽  
Good Consistency ◽  
The Given ◽  
Neutron Star Radius ◽  
Star Structure

Using the modern equations of state derived from microscopic calculations, we have calculated the neutron star structure. For the neutron star, we have obtained a minimum mass about 0.1 M⊙ which is nearly independent of the equation of state, and a maximum mass between 1.47 M⊙ and 1.98 M⊙ which is strongly dependent on the equation of state. It is shown that among the equations of state of neutron star matter which we have used, the stiffest one leads to higher maximum mass and radius and lower central density. It is seen that the given maximum mass for the Reid-93 equation of state shows a good consistency with the accurate observations of radio pulsars. We have indicated that the thickness of neutron star crust is very small compared to the predicted neutron star radius.

EQUATION OF STATE, MASS, RADIUS, MOMENT OF INERTIA, AND SURFACE GRAVITATIONAL REDSHIFT FOR NEUTRON STARS

1994 ◽  
Vol 03 (04) ◽  
pp. 813-838 ◽  
Author(s):  
G. BAO ◽  
E. ØSTGAARD ◽  
B. DYBVIK
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Total Mass ◽  
Equations Of State ◽  
Maximum Mass ◽  
Neutron Star Matter ◽  
Solar Mass ◽  
Moments Of Inertia ◽  
Gravitational Fields

We have calculated total masses and radii of neutron stars from the Tolman-Oppenheimer-Volkoff (TOV) equations (for matter in equilibrium in gravitational fields) and different equations of state for neutron-star matter. The calculations are done for different input central densities. We have also obtained pressure and density as functions of distance from the centre of the star, and moments of inertia and surface gravitational redshifts as functions of the total mass of the star. The maximum mass M max is for all equations of state in our calculations given by 1.65M⊙<M max <2.43M⊙ (where M⊙ is the solar mass), which agrees very well with “experimental” results. Corresponding radii R are given by 8.8 km <R<12.7 km , and a smaller central density will, in general, give a smaller mass and a larger radius.

scholarly journals Searching optimum equations of state of neutron star matter in strong magnetic fields with rotation

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
C Watanabe ◽  
K Yanase ◽  
N Yoshinaga
Keyword(s):  
Neutron Star ◽  
Magnetic Fields ◽  
Equations Of State ◽  
Mean Field ◽  
Maximum Mass ◽  
Neutron Star Matter ◽  
Solar Mass ◽  
Strong Magnetic Fields ◽  
Relativistic Mean Field ◽  
Rho A

Abstract Masses and radii of neutron stars are obtained in the presence of strong magnetic fields together with rotation. Mass-radius relations are calculated using 11 equations of state (EoSs: GM1, TM1-a, TM1-b, TM2$\omega\rho$-a, TM2$\omega\rho$-b, NL3-a, NL3-b, NL3$\omega\rho$-a, NL3$\omega\rho$-b, DDME2-a and DDME2-b) in relativistic mean field (RMF) theory. Obtained masses are over and around twice the solar mass ($M_\odot$) for all EoSs in the presence of strong magnetic fields of $3 \times 10^{18}$ G at the center. For NL3$\omega\rho$-a and NL3$\omega\rho$-b EoSs, masses are more than $M=2.17\,M_\odot$(observed maximum mass: $2.14\,M_\odot$) even without magnetic fields. Rotational effects are found to be insignificant in any case, at least up to the Kepler frequency. Suitable EoSs are also selected concerning the constraint on the radius of a neutron star.

scholarly journals Gravitational-Wave Constraints on the Neutron-Star-Matter Equation of State

2018 ◽  
Vol 120 (17) ◽  
Author(s):  
Eemeli Annala ◽  
Tyler Gorda ◽  
Aleksi Kurkela ◽  
Aleksi Vuorinen
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Gravitational Wave ◽  
Neutron Star Matter

scholarly journals Astrophysical implications of neutron star inspiral and coalescence

2020 ◽  
Vol 29 (11) ◽  
pp. 2041015
Author(s):  
John L. Friedman ◽  
Nikolaos Stergioulas
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Maximum Mass ◽  
X Ray ◽  
Spectral Bands ◽  
Heaviest Elements ◽  
X Ray Binaries

The first inspiral of two neutron stars observed in gravitational waves was remarkably close, allowing the kind of simultaneous gravitational wave and electromagnetic observation that had not been expected for several years. Their merger, followed by a gamma-ray burst and a kilonova, was observed across the spectral bands of electromagnetic telescopes. These GW and electromagnetic observations have led to dramatic advances in understanding short gamma-ray bursts; determining the origin of the heaviest elements; and determining the maximum mass of neutron stars. From the imprint of tides on the gravitational waveforms and from observations of X-ray binaries, one can extract the radius and deformability of inspiraling neutron stars. Together, the radius, maximum mass, and causality constrain the neutron-star equation of state, and future constraints can come from observations of post-merger oscillations. We selectively review these results, filling in some of the physics with derivations and estimates.

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