On Magnetic Fields in Rotating Nuclear Matter Cores of Stellar Dimensions

Boshkayev, Kuantay; Rotondo, Michael F.; Ruffini, Remo

doi:10.1142/s2010194512006265

Cited by 5 publications

(11 citation statements)

References 16 publications

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“…(11-12) can now be used to calculate the induced magnetic field both in the core and the core-crust interface shell surrounding it. Following Boshkayev et al (2012), in order to estimate the rotationally induced magnetic field, we describe the core and the core-crust interface using a simplified model based on the previous works by Rotondo et al (2011c,a). The distribution of N p protons, n p , is assumed as constant within the core radius R c = ∆ /(m π c)N 1/3 p , where ∆ is a parameter such that ∆ ≈ 1 (∆ < 1) corresponds to nuclear (supranuclear) densities when applied to ordinary nuclei, i.e.…”

Section: Influence Of the Rotationally Induced Magnetic Fieldmentioning

confidence: 99%

On the Magnetic Field of Pulsars With Realistic Neutron Star Configurations

Belvedere

Rueda

Ruffini

2015

ApJ

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We have recently developed a neutron star model fulfilling global and not local charge neutrality, both in the static and in the uniformly rotating cases. The model is described by the coupled Einstein-Maxwell-ThomasFermi (EMTF) equations, in which all fundamental interactions are accounted for in the framework of general relativity and relativistic mean field theory. Uniform rotation is introduced following the Hartle's formalism. We show that the use of realistic parameters of rotating neutron stars obtained from numerical integration of the self-consistent axisymmetric general relativistic equations of equilibrium leads to values of the magnetic field and radiation efficiency of pulsars very different from estimates based on fiducial parameters assuming a neutron star mass, M = 1.4 M ⊙ , radius R = 10 km, and moment of inertia, I = 10 45 g cm 2 . In addition, we compare and contrast the magnetic field inferred from the traditional Newtonian rotating magnetic dipole model with respect to the one obtained from its general relativistic analog which takes into due account the effect of the finite size of the source. We apply these considerations to the specific high-magnetic field pulsars class and show that, indeed, all these sources can be described as canonical pulsars driven by the rotational energy of the neutron star, and with magnetic fields lower than the quantum critical field for any value of the neutron star mass.

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Section: Influence Of the Rotationally Induced Magnetic Fieldmentioning

confidence: 99%

On the Magnetic Field of Pulsars With Realistic Neutron Star Configurations

Belvedere

Rueda

Ruffini

2015

ApJ

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“…with its exterior counterpart (see Hartle (1967) and Appendix A). It is worth to underline that the influence of the induced magnetic field owing to the rotation of the charged core of the neutron star in the globally neutral case is negligible (Boshkayev et al, 2012b). In fact, for a rotating neutron star of period P = 10 ms and radius R ∼ 10 km, the radial component of the magnetic field B r in the core interior reaches its maximum at the poles with a value B r ∼ 2.9 × 10 −16 B c , where B c = m 2 e c 3 /(e ) ≈ 4.4 × 10 13 G is the critical magnetic field for vacuum polarization.…”

Section: Hartle Slow Rotation Approximationmentioning

confidence: 99%

Uniformly rotating neutron stars in the global and local charge neutrality cases

et al. 2014

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In our previous treatment of neutron stars, we have developed the model fulfilling global and not local charge neutrality. In order to implement such a model, we have shown the essential role by the Thomas-Fermi equations, duly generalized to the case of electromagnetic field equations in a general relativistic framework, forming a coupled system of equations that we have denominated Einstein-Maxwell-Thomas-Fermi (EMTF) equations. From the microphysical point of view, the weak interactions are accounted for by requesting the β stability of the system, and the strong interactions by using the σ-ω-ρ nuclear model, where σ, ω and ρ are the mediator massive vector mesons. Here we examine the equilibrium configurations of slowly rotating neutron stars by using the Hartle formalism in the case of the EMTF equations indicated above. We integrate these equations of equilibrium for different central densities ρ c and circular angular velocities Ω and compute the mass M , polar R p and equatorial R eq radii, angular momentum J, eccentricity ǫ, moment of inertia I, as well as quadrupole moment Q of the configurations. Both the Keplerian mass-shedding limit and the axisymmetric secular instability are used to construct the new mass-radius relation. We compute the maximum and minimum masses and rotation frequencies of neutron stars. We compare and contrast all the results for the global and local charge neutrality cases. ⊙ Static J = 0.2 J = 0.5 J = 0.7 J = 1.0 J = 1.2 J = 1.3 Keplerian Secular Inst. ⊙ Static J = 0.2 J = 0.5 J = 0.7 J = 1.0 J = 1.2 J = 1.3 Keplerian Secular Inst.

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“…It would be interesting to perform a detailed calculation taking into account the effects of general relativity as well as of the magnetic field on the transition surface induced by rotation (see Ref. [52]) and the centrifugal potential acting on the shell. However, such calculation is out of the scope of this work and will be presented elsewhere.…”

Section: 33mentioning

confidence: 99%

Surface tension of the core-crust interface of neutron stars with global charge neutrality

Rueda

Ruffini

et al. 2014

Phys. Rev. C

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It has been shown recently that taking into account strong, weak, electromagnetic, and gravitational interactions, and fulfilling the global charge neutrality of the system, a transition layer will happen between the core and crust of neutron stars, at the nuclear saturation density. We use relativistic mean field theory together with the Thomas-Fermi approximation to study the detailed structure of this transition layer and calculate its surface and Coulomb energy. We find that the surface tension is proportional to a power-law function of the baryon number density in the core bulk region. We also analyze the influence of the electron component and the gravitational field on the structure of the transition layer and the value of the surface tension to compare and contrast with known phenomenological results in nuclear physics. Based on the above results we study the instability against Bohr-Wheeler surface deformations in the case of neutron stars obeying global charge neutrality. Assuming the core-crust transition at nuclear density ρ core ≈ 2.7 × 10 14 g cm −3 , we find that the instability sets the upper limit to the crust density, ρ crit crust ≈ 1.2 × 10 14 g cm −3 . This result implies a nonzero lower limit to the maximum electric field of the core-crust transition surface and makes inaccessible a limit of quasilocal charge neutrality in the limit ρ crust = ρ core . The general framework presented here can be also applied to study the stability of sharp phase transitions in hybrid stars as well as in strange stars, both bare and with outer crust. The results of this work open the way to a more general analysis of the stability of these transition surfaces, accounting for other effects such as gravitational binding, centrifugal repulsion, magnetic field induced by rotating electric field, and therefore magnetic dipole-dipole interactions.

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On Magnetic Fields in Rotating Nuclear Matter Cores of Stellar Dimensions

Cited by 5 publications

References 16 publications

On the Magnetic Field of Pulsars With Realistic Neutron Star Configurations

On the Magnetic Field of Pulsars With Realistic Neutron Star Configurations

Uniformly rotating neutron stars in the global and local charge neutrality cases

Surface tension of the core-crust interface of neutron stars with global charge neutrality

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