Effect of the equation of state on the maximum mass of differentially rotating neutron stars

2016 ◽  
Vol 463 (3) ◽  
pp. 2667-2679 ◽  
Author(s):  
A. M. Studzińska ◽  
M. Kucaba ◽  
D. Gondek-Rosińska ◽  
L. Villain ◽  
M. Ansorg
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Maximum Mass

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.

scholarly journals The Effects of Nuclear Forces on the Maximum Mass Limit of Neutron Stars

1971 ◽  
Vol 46 ◽  
pp. 352-355
Author(s):  
Sachiko Tsuruta
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Interaction ◽  
Maximum Mass ◽  
Nuclear Forces ◽  
Mass Limit ◽  
Improved Model

The original models of neutron stars must be improved by including effects of nuclear interaction. This paper compares the models reached by various groups, and presents an improved model by the Kyoto group. The maximum mass varies between 0.2 M⊙ and 3 M⊙ in the various models. The Vγ model is recommended for use in the absence of further information on the equation of state at high densities.

NEUTRON STARS AND THE COHERENT NUCLEAR INTERACTION

1995 ◽  
Vol 04 (04) ◽  
pp. 531-548 ◽  
Author(s):  
E. DEL GIUDICE ◽  
R. MELE ◽  
G. PREPARATA ◽  
C. GUALDI ◽  
G. MANGANO ◽  
...  
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Interaction ◽  
Central Density ◽  
Maximum Mass ◽  
Minimum Period ◽  
Novel Approach ◽  
Coherent Interaction ◽  
New Equation ◽  
The Masses

In the framework of a novel approach to the dynamics of nuclei and large collections of nucleons, which fully exploits the coherent interaction among π’s, nucleons and Δ’s, we derive a new equation of state for neutronic matter. By introducing it in the Tolman-Oppenheimer-Volkof equations we derive the masses and radii of neutron stars as a function of the central density. We obtain a maximum mass Mmax≃2.7 Mʘ and a minimum period of rotation Tmin=0.8 msec.

HADRON-QUARK PHASE TRANSITION AND ANTIKAON CONDENSATION IN NEUTRON STARS

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2481-2484
Author(s):  
H. SHEN ◽  
F. YANG ◽  
P. YUE
Keyword(s):  
Field Theory ◽  
Phase Transition ◽  
Equation Of State ◽  
Neutron Stars ◽  
Mean Field Theory ◽  
Mean Field ◽  
Maximum Mass ◽  
Relativistic Mean Field ◽  
The Core ◽  
Quark Phase

We study the hadron-quark phase transition and antikaon condensation which may occur in the core of massive neutron stars. The relativistic mean field theory is used to describe the hadronic phase, while the Nambu-Jona-Lasinio model is adopted for the quark phase. We find that the hadron-quark phase transition is very sensitive to the models used. The appearance of deconfined quark matter and antikaon condensation can soften the equation of state at high density and lower the maximum mass of neutron stars.

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.

Equation of State and the Maximum Mass of Neutron Stars

1988 ◽  
Vol 61 (22) ◽  
pp. 2518-2521 ◽  
Author(s):  
M. Prakash ◽  
T. L. Ainsworth ◽  
J. M. Lattimer
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Maximum Mass

A FUZZY BAG MODEL FOR BARYON-DIBARYON PHASE TRANSITION IN NEUTRON STARS

2011 ◽  
Vol 20 (supp02) ◽  
pp. 152-159
Author(s):  
ALBERTO S. S. ROCHA ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
HELIO T. COELHO
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Neutron Stars ◽  
Internal Structure ◽  
External Medium ◽  
Nuclear Model ◽  
Maximum Mass ◽  
Bag Model ◽  
Abrupt Transition ◽  
Self Energy

We propose a model for dibaryon stars which takes into account the internal structure of nucleons via a fuzzy bag model. This choice of nuclear model avoids nucleon self-energy divergences as in the MIT model, and also considers a softer bag surface, thus eliminating the disadvantage of an abrupt transition between the interior of the bag and the external medium. We obtain results for the equation of state and for the mass-radius relation for the dibaryon star. Our results indicate a smaller maximum mass for dibaryon stars as compared to neutron stars, mainly due to the relaxation of the interior Fermi pressure in the dibaryon-populated star core.

scholarly journals A lower bound on the maximum mass if the secondary in GW190814 was once a rapidly spinning neutron star

2020 ◽  
Vol 499 (1) ◽  
pp. L82-L86 ◽  
Author(s):  
Elias R Most ◽  
L Jens Papenfort ◽  
Lukas R Weih ◽  
Luciano Rezzolla
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Equation Of State ◽  
Lower Bound ◽  
Neutron Stars ◽  
Compact Objects ◽  
Maximum Mass ◽  
Secondary Neutron ◽  
Massive Neutron Star ◽  
The Masses

ABSTRACT The recent detection of GW190814 featured the merger of a binary with a primary having a mass of $\sim 23\, \mathrm{ M}_{\odot }$ and a secondary with a mass of $\sim 2.6\, \mathrm{ M}_{\odot }$. While the primary was most likely a black hole, the secondary could be interpreted as either the lightest black hole or the most massive neutron star ever observed, but also as the indication of a novel class of exotic compact objects. We here argue that although the secondary in GW190814 is most likely a black hole at merger, it needs not be an ab-initio black hole nor an exotic object. Rather, based on our current understanding of the nuclear-matter equation of state, it can be a rapidly rotating neutron star that collapsed to a rotating black hole at some point before merger. Using universal relations connecting the masses and spins of uniformly rotating neutron stars, we estimate the spin, $0.49_{-0.05}^{+0.08} \lesssim \chi \lesssim 0.68_{-0.05}^{+0.11}$, of the secondary – a quantity not constrained so far by the detection – and a novel strict lower bound on the maximum mass, $M_{_{\mathrm{TOV}}}\gt 2.08^{+0.04}_{-0.04}\, \, \mathrm{ M}_{\odot }$ and an optimal bound of $M_{_{\mathrm{TOV}}}\gt 2.15^{+0.04}_{-0.04}\, \, \mathrm{ M}_{\odot }$, of non-rotating neutron stars, consistent with recent observations of a very massive pulsar. The new lower bound also remains valid even in the less likely scenario in which the secondary neutron star never collapsed to a black hole.

scholarly journals Protoneutron stars and neutron stars

2000 ◽  
Vol 177 ◽  
pp. 663-664
Author(s):  
D. Gondek-Rosińska ◽  
P. Haensel ◽  
J. L. Zdunik
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Dense Matter ◽  
Early Evolution ◽  
Maximum Mass ◽  
Standard Equation ◽  
Nuclear Incompressibility ◽  
Protoneutron Stars ◽  
Protoneutron Star

AbstractWe find constraints on minimum and maximum mass of ordinary neutron stars imposed by their early evolution (protoneutron star stage). We calculate models of protoneutron stars using a realistic standard equation of state of hot, dense matter valid for both supranuclear and subnuclear densities. Results for different values of the nuclear incompressibility are presented.

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