scholarly journals Anisotropic Charged Fluid Sphere in Isotropic Coordinates

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Neeraj Pant ◽  
N. Pradhan ◽  
Ksh. Newton Singh

We have presented a class of charged superdense star models, starting with a static spherically symmetric metric in isotropic coordinates for anisotropic fluid by considering Hajj-Boutros-(1986) type metric potential and a specific choice of electrical intensity E and anisotropy factor Δ which involve charge parameter K and anisotropy parameter α. The solution is well behaved for all the values of Schwarzschild compactness parameter u lying in the range 0<u≤0.2086, for all values of charge parameter K lying in the range 0.04≤K≤0.111 , and for all values of anisotropy parameter α lying in the range 0.016≥α≥0. With the increase in α, the values of K and u decrease. Further, we have constructed a superdense star model with all degree of suitability. The solution so obtained is utilized to construct the models for superdense star like neutron stars ρb=2.7×1014 g/cm3 and strange quark stars  ρb=4.6888×1014 g/cm3 . For K=0.06 and α=0.01, the maximum mass of neutron star is observed as M=1.53 M⊙ and radius R=11.48 km. Further for strange quark stars M=1.16 M⊙ and R=8.71 km are obtained.

2011 ◽  
Vol 20 (09) ◽  
pp. 1675-1687 ◽  
Author(s):  
BASANTI DAS ◽  
PRATAP CHANDRA RAY ◽  
IRINA RADINSCHI ◽  
FAROOK RAHAMAN ◽  
SAIBAL RAY

In this paper we study the isotropic cases of static charged fluid spheres in general relativity. For this purpose we consider two different specializations and under these we solve the Einstein–Maxwell field equations in isotropic coordinates. The analytical solutions thus obtained are matched to the exterior Reissner–Nordström solutions which concern the values for the metric coefficients eν and eμ. We derive the pressure, density and pressure-to-density ratio at the center of the charged fluid sphere and boundary R of the star. Our conclusion is that static charged fluid spheres provide a good connection to compact stars.


2019 ◽  
Vol 22 (4) ◽  
pp. 311-317
Author(s):  
Hidezumi Terazawa

New forms of matter such as super-hypernuclei (strange quark matter) and superhypernuclear stars (strange quark stars) as candidates for dark matter are discussed in some detail, based on the so-called "Bodmer–Terazawa–Witten hypothesis" assuming that they are stable absolutely or quasi-stable (decaying only weakly).


2002 ◽  
Vol 567 (1) ◽  
pp. L63-L66 ◽  
Author(s):  
Krzysztof Belczynski ◽  
Tomasz Bulik ◽  
Włodzimierz Kluźniak

2021 ◽  
Vol 922 (2) ◽  
pp. 149
Author(s):  
Debabrata Deb ◽  
Banibrata Mukhopadhyay ◽  
Fridolin Weber

Abstract We investigate the properties of anisotropic, spherically symmetric compact stars, especially neutron stars (NSs) and strange quark stars (SQSs), made of strongly magnetized matter. The NSs are described by the SLy equation of state (EOS) and the SQSs by an EOS based on the MIT Bag model. The stellar models are based on an a priori assumed density dependence of the magnetic field and thus anisotropy. Our study shows that not only the presence of a strong magnetic field and anisotropy, but also the orientation of the magnetic field itself, have an important influence on the physical properties of stars. Two possible magnetic field orientations are considered: a radial orientation where the local magnetic fields point in the radial direction, and a transverse orientation, where the local magnetic fields are perpendicular to the radial direction. Interestingly, we find that for a transverse orientation of the magnetic field, the stars become more massive with increasing anisotropy and magnetic-field strength and increase in size since the repulsive, effective anisotropic force increases in this case. In the case of a radially oriented magnetic field, however, the masses and radii of the stars decrease with increasing magnetic-field strength because of the decreasing effective anisotropic force. Importantly, we also show that in order to achieve hydrostatic equilibrium configurations of magnetized matter, it is essential to account for both the local anisotropy effects as well as the anisotropy effects caused by a strong magnetic field. Otherwise, hydrostatic equilibrium is not achieved for magnetized stellar models.


2012 ◽  
Vol 8 (S291) ◽  
pp. 61-66 ◽  
Author(s):  
Fridolin Weber ◽  
Milva Orsaria ◽  
Hilario Rodrigues ◽  
Shu-Hua Yang

AbstractThis paper gives an brief overview of the structure of hypothetical strange quarks stars (quark stars, for short), which are made of absolutely stable 3-flavor strange quark matter. Such objects can be either bare or enveloped in thin nuclear crusts, which consist of heavy ions immersed in an electron gas. In contrast to neutron stars, the structure of quark stars is determined by two (rather than one) parameters, the central star density and the density at the base of the crust. If bare, quark stars possess ultra-high electric fields on the order of 1018 to 1019 V/cm. These features render the properties of quark stars more multifaceted than those of neutron stars and may allow one to observationally distinguish quark stars from neutron stars.


2020 ◽  
Vol 101 (6) ◽  
Author(s):  
Cheng-Ming Li ◽  
Shu-Yu Zuo ◽  
Yan Yan ◽  
Ya-Peng Zhao ◽  
Fei Wang ◽  
...  

2019 ◽  
Vol 879 (1) ◽  
pp. 44 ◽  
Author(s):  
Magdalena Szkudlarek ◽  
Dorota Gondek-Rosińska ◽  
Loïc Villain ◽  
Marcus Ansorg

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