共查询到20条相似文献，搜索用时 46 毫秒
1.
We have calculated some properties of spin polarized strange quark matter(SQM) in a strong magnetic field at zero temperature using the MIT bag model.We showed that the equation of state of spin polarized SQM is stiffer than that for unpolarized cases.We have also computed the structural properties of a spin polarized strange quark star(SQS) and found that the presence of a magnetic field leads to a more stable SQS when compared to the structural properties of an unpolarized SQS. 相似文献
2.
We study quarkand strangequarkmatter in the contextof generalrelativity.For this purpose,we solve Einstein's field equations for quark and strange quark matter in spherical symmetric space-times. We analyze strange quark matter for the different equations of state (EOS) in the spherical symmetric space-times,thus we are able to obtain the space-time geometries of quark and strange quark matter. Also,we discuss the features of the obtained solutions. The obtained solutions are consistent with the results of Brookhaven Laboratory,i.e. the quark-gluon plasma has a vanishing shear (i.e. quark-gluon plasma is perfect). 相似文献
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Models of strange quark stars with a crust consisting of atomic nuclei and degenerate electrons, maintained by an electrostatic
barrier at the surface of the strange quark matter, are investigated for a realistic range of parameters of the MIT bag model.
The density at which neutrons escape from nuclei, ρ = ρdrip, is taken as the maximum possible boundary density of the crust. Series of strange stars are calculated as a function of
central density. Configurations with masses of 1.44 and 1.77 M{ie330-1} and a gravitational redshift Zs = 0.23, corresponding to the best-known observational data, are investigated. The presence of a crust results in the existence
of a minimum mass for strange stars, and also helps to explain the glitch phenomenon of pulsars within the framework of the
existence of strange quark matter.
Translated from Astrofizika, Vol. 42, No. 3, pp. 439–448, July–September, 1999. 相似文献
6.
《天文和天体物理学研究(英文版)》2015,(7)
The fact that a fermion system in an external magnetic field breaks the spherical symmetry suggests that its intrinsic geometry is axisymmetric rather than spherical. In this work we analyze the impact of anisotropic pressures, due to the presence of a magnetic field, in the structure equations of a magnetized quark star.We assume a cylindrical metric and an anisotropic energy momentum tensor for the source. We found that there is a maximum magnetic field that a strange star can sustain, closely related to the violation of the virial relations. 相似文献
7.
The behaviour of the magnetic field of a neutron star with a superconducting quark matter core is investigated in the framework of the Ginzburg-Landau theory. We take into account the simultaneous coupling of the diquark condensate field to the usual magnetic and to the gluomagnetic gauge fields. We solve the Ginzburg-Landau equations by properly taking into account the boundary conditions, in particular, the gluon confinement condition. We found the distribution of the magnetic field in both the quark and hadronic phases of the neutron star and show that the magnetic field penetrates into the quark core in the form of quark vortices due to the presence of Meissner currents. 相似文献
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Questions of the equilibrium, stability, and observational manifestations of strange stars are considered, in which electrical
neutralization of the quark matter is provided by positrons, as occurs for some sets of bag parameters resulting in a stiffer
equation of state. Such models consist entirely of self-contained, strange quark matter and their maximum mass reaches 2.4–2.5
M⊙ with a radius of 13–14 km. The cooling of such strange quark stars both in the absence and in the presence of mass accretion
is investigated. It is shown that in the absence of mass accretion onto the strange star, the dependence of temperature (T,
K) on age (t, yr) depends very little on the mass of the configuration and has the form T ≈ 2.3·108r−1/5. If the star’s initial temperature is sufficiently high (T0≥2·1010K), then the total number of electron-positron pairs emitted does not depend on it and is determined only by the total mass
of the configuration. In the case of accretion, the annihilation of electrons of the infalling fatter with positrons of the
strange quark matter results in the emission of γ-rays with an energy of∼0.5 MeV, by observing which one can distinguish candidates
for strange stars. The maximum temperature of strange stars with mass accretion is calculated.
Translated from Astrofizika, Vol. 42, No. 4, pp. 617–630, October–December, 1999. 相似文献
10.
G. S. Hajyan 《Astrophysics》2001,44(3):387-392
The distributions of electrons and of electrical potential at the free surface of strange quark matter are determined within the framework of the MIT bag model. It is shown that, with allowance for the decay of quarks near the surface due to the outward escape of electrons, the electric charge density of quarks at the surface increases by a factor of 17-25, the thickness of the transitional layer decreases from 230 Fm to 15 Fm, and the field strength increases by a factor of 1.7. The difference between the chemical potentials of electrons at the surface and in deep layers decreases from 7 MeV to 0.8 MeV, which increases the limiting possible density of ordinary matter above a strange quark star. 相似文献
11.
This paper presents a family of two-parametric interior solutions of Einstein–Maxwell field equations in general relativity for a static spherically symmetric distribution of a charged perfect fluid with particular form of charge distribution. This class of solutions gives us wide range of parameters, n and K, for which the solutions are well behaved hence, suitable for modeling of compact star (e. g. bare strange quark star). The mass of star is maximized with all degree of suitability by assuming the stellar “surface” density equal to strange (quark) matter density at zero pressure. It is hoped that our investigation may be of some help in connection of some study of stellar structure. 相似文献
12.
An extensive set of realistic equations of state for superdense matter with a quark phase transition is derived on the basis of the three equations of state for neutron matter and the eight variants of strange quark-gluon plasmas in the MIT quark bag model. The characteristics of the phase transitions are described and the calculated equations of state with a density jump are studied in detail. 相似文献
13.
《天文和天体物理学研究(英文版)》2017,(2)
The properties of strange star matter are studied in the equivparticle model with inclusion of non-Newtonian gravity. It is found that the inclusion of non-Newtonian gravity makes the equation of state stiffer if Witten's conjecture is true. Correspondingly, the maximum mass of strange stars becomes as large as two times the solar mass, and the maximum radius also becomes bigger. The coupling to boson mass ratio has been constrained within the stability range of strange quark matter. 相似文献
14.
A broad sample of computed realistic equations of state of superdense matter with a quark phase transition is used to construct a series of models of neutron stars with a strange quark core. The integral characteristics of the stellar configurations are obtained: gravitational mass, rest mass, radius, relativistic moment of inertia, and red shift from the star's surface, as well as the mass and radius of the quark core within the allowable range of values for the central pressure. The parameters of some of the characteristic configurations of the calculated series are also given and these are studied in detail. It is found that a new additional region of stability for neutron stars with strange quark cores may exist for some models of the equation of state. 相似文献
15.
The conversion from neutron stars with different equation of states (EOSs) for neutron matter into strange stars with different EOSs for strange quark matter has been studied in a general relativistic numerical calculation in this paper. For hot neutron stars, their conversion may lead to great variations in their rotation periods, of which the magnitude would be greatly dependent upon the EOS for neutron matter, and of which the timescale would be greatly determined by the EOS for strange matter. This phenomenon appears as giant glitches, which might provide a probe of EOSs for both neutron matter and strange matter. But for cold neutron stars, their conversion may result in a population of gamma-ray bursts. 相似文献
16.
In the framework of the MIT bag model we consider absolutely stable strange quark matter consisting of u, d, and s quarks and electrons. For a realistic range of parameters of the quark bag we compute the threshold density for the appearance of strange quark matter that is realized on the surface of self-sustaining strange stars. On the basis of twelve calculated equations of state we give a detailed study of the series of configurations of strange stars consistent with the best known observational data. We show that the binding energy of the models depends essentially on the quark-gluon interaction constant c.Translated fromAstrofizika, Vol. 37, No. 3, 1994.The authors are grateful to E. V. Chubaryan and A. M. Atoyan for assistance in overcoming the information blockade. The present paper was written in the framework of area 46/101 93-353, supported by the Ministry of Higher Education and Science of the Republic of Armenia. 相似文献
17.
Raka Dona Ray Mandal Sushan Konar Mira Dey Jishnu Dey 《Monthly notices of the Royal Astronomical Society》2009,399(2):822-826
The single glitch observed in PSR B1821−24, a millisecond pulsar in M28, is unusual on two counts. First, the magnitude of this glitch is at least an order of magnitude smaller (Δν/ν∼ 10−11 ) than the smallest glitch observed to date. Secondly, all other glitching pulsars have strong magnetic fields with B ≳ 1011 G and are young, whereas PSR B1821−24 is an old recycled pulsar with a field strength of 2.25 × 109 G . We have earlier suggested that some of the recycled pulsars could actually be strange quark stars. In this work, we argue that the crustal properties of such a strange pulsar are just right to give rise to a glitch of this magnitude, explaining the scarcity of larger glitches in millisecond pulsars. 相似文献
18.
《天文和天体物理学研究(英文版)》2017,(10)
We calculate the mass-radius relationship of quark stars with the magnetized densitydependent quark mass model in this work, considering two magnetic field geometries: a statistically isotropic, tangled field and a force-free configuration. In both cases, magnetic field production decreases in the case of maximum quark star mass. Furthermore, a tangled, isotropic magnetic field has a relatively smaller impact on the mass and radius, compared to the force-free configuration, which implies that the geometry of the interior magnetic field is at least as important as the field strength itself when the influence of the strong magnetic field on the mass and radius is assessed. 相似文献
19.
This is a study of the stability of strange dwarfs, superdense stars with a small self-confining core (M
core
< 0.02 M⊙) containing strange quark matter and an extended crust consisting of atomic nuclei and degenerate electron gas. The mass
and radius of these stars are of the same orders as those of ordinary white dwarfs. It is shown that any study of their stability
must examine the dependence of the mass on two variables, which can, for convenience, be taken to be the rest mass (total
baryon mass) of the quark core and the energy density ρ
tr
of the crust at the surface of the quark core. The range of variation of these quantities over which strange dwarfs are stable
is determined. This region is referred to as the stability valley for strange dwarfs. The mass and radius from theoretical
models of strange dworfs are compared with observational data obtained through the HIPPARCOS program and the most probable
candidate strange dwarfs are identified. 相似文献
20.
《New Astronomy》2007,12(3):165-168
We derive the bulk viscous damping timescale of hybrid stars, neutron stars with quark matter core. The r-mode instability windows of the stars show that the theoretical results are consistent with the rapid rotation pulsar data, which may give an indication for the existence of quark matter in the interior of neutron stars. Hybrid stars instead of neutron or strange stars may lead to submillisecond pulsars. 相似文献