Moments of inertia for neutron and strange stars: Limits derived for the Crab pulsar

  title={Moments of inertia for neutron and strange stars: Limits derived for the Crab pulsar},
  author={Michał Bejger and Paweł Haensel},
  journal={Astronomy and Astrophysics},
Recent estimates of the properties of the Crab nebula are used to derive constraints on the moment of inertia, mass and radius of the pulsar. To this purpose, we employ an approximate formula combining these three parameters. Our "empirical formula" I ' a(x)MR 2 ,w herex = (M=M)(km=R), is based on numerical results obtained for thirty theoretical equations of state of dense matter. The functions a(x) for neutron stars and strange stars are qualitatively dierent. For neutron stars aNS(x)= x=(0:1… Expand

Figures from this paper

Quadrupole moments of rotating neutron stars and strange stars
We present results for models of neutron stars and strange stars constructed using the Hartle-Thorne slow-rotation method with a wide range of equations of state, focusing on the values obtained forExpand
Universal relations for the Keplerian sequence of rotating neutron stars
We investigate the Keplerian (mass-shedding) sequence of rotating neutron stars. Twelve different equations of state are used to describe the nuclear structure. We find four fitting relations whichExpand
Parameters of rotating neutron stars with and without hyperons
The discovery of a 2 Msun neutron star provided a robust constraint for the theory of exotic dense matter, bringing into question the existence of strange baryons in the interiors of neutron stars.Expand
An upper bound on the energy of a gravitationally redshifted electron-positron annihilation line from the Crab pulsar
We present a causally consistent and pulsationally stable two component neutron star model on the basis of the criterion that for each assigned value of σ(≡(P0/E0) ≡ the ratio of central pressure toExpand
Neutron star sequences and the starquake glitch model for the Crab and the Vela pulsars
We construct for the first time, the sequences of stable neutron star (NS) models capable of explaining simultaneously, the glitch healing parameters, Q, of both the pulsars, the Crab (Q≥0.7) and theExpand
A possible representation for the neutron star PSR J0437-4715
Abstract.A construction and analysis of an exact solution to Einstein's field equations with the source of matter being an anisotropic fluid that allows to model compact stars with a rate ofExpand
On the universality of I-Love-Q relations in magnetized neutron stars
Recently, general relations among the quadrupole moment (Q), the moment of inertia (I) and the tidal deformability (Love number) of a neutron star were shown to exist. They are nearly independent ofExpand
A starquake model for the Vela pulsar
The measured values of the glitch healing parameter, Q, of the Vela pulsar are found to be inconsistent with the starquake mechanism for glitch generation in various neutron star (NS) models, basedExpand
Maximum mass, moment of inertia and compactness of relativistic stars
A number of recent works have highlighted that it is possible to express the properties of general-relativistic stellar equilibrium configurations in terms of functions that do not depend on theExpand
Accelerated expansion of the Crab Nebula and evaluation of its neutron-star parameters
A model of an accelerated expansion of the Crab Nebula powered by the spinning-down Crab pulsar is proposed, in which time dependence of the acceleration is connected to the evolution of pulsarExpand


A unified equation of state of dense matter and neutron star structure
An equation of state (EOS) of neutron star matter, describing both the neutron star crust and the liquid core, is calculated. It is based on the eective nuclear interaction SLy of the Skyrme type,Expand
Neutron Star Structure and the Equation of State(Nuclear Astrophysics,New Frontiers in QCD 2010-Exotic Hadron Systems and Dense Matter-)
The structure of neutron stars is considered from theoretical and observational perspectives. We demonstrate an important aspect of neutron star structure: the neutron star radius is primarilyExpand
Structure and stability of rotating relativistic neutron stars
The aim of this work is twofold : (1) We investigate the influence of rotation on the bulk properties of neutron stars. (2) The limiting angular velocities at which instability against gravitationalExpand
Roles of Hyperons in Neutron Stars
We examine the roles the presence of hyperons in the cores of neutron stars may play in determining global properties of these stars. The study is based on estimates that hyperons appear in neutronExpand
An Optical Study of the Circumstellar Environment Around the Crab Nebula
Long-slit spectra of two peripheral regions around the Crab Nebula show no H(alpha) emission down to a flux level of 1.5 x 10(exp -7)erg/sq cm s sr (0.63 Rayleigh), corresponding to an emissionExpand
An Effective equation of state for dense matter with strangeness
Abstract An effective equation of state which generalizes the Lattimer-Swesty equation for nuclear matter is presented for matter at supernuclear densities including strange baryons. It contains anExpand
Observations of the Crab Nebula and Its Pulsar in the Far-Ultraviolet and in the Optical* **
We present far-UV observations of the Crab Nebula and its pulsar made with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. Broad, blueshifted absorption arising in theExpand
Neutron star moments of inertia
An approximation for the moment of inertia of a neutron star in terms of only its mass and radius is presented, and insight into it is obtained by examining the behavior of the relativisticExpand
Neutron Stars Are Giant Hypernuclei
Neutron stars are studied in the framework of Lagrangian field theory of interacting nucleons, hyperons, and mesons, which is solved in the mean field approximation. The theory is constrained toExpand
Motions and Structure of the Filamentary Envelope of the Crab Nebula
Proper motions have been measured for 132 line-emitting filaments in the Crab Nebula on direct plates taken with the 100 and 200-inch telescopes. These motions, if assumed constant and extrapolatedExpand