A family of charged compact objects with anisotropic pressure

Abstract

Utilizing an ansatz developed by Maurya et al. we present a class of exact solutions of the Einstein-Maxwell field equations describing a spherically symmetric compact object. A detailed physical analysis of these solutions in terms of stability, compactness and regularity indicates that these solutions may be used to model strange star candidates. In particular, we model the strange star candidate Her X-1 and show that our solution conforms to observational data to an excellent degree of accuracy. An interesting and novel phenomenon which arises in this model is the fact that the relative difference between the electromagnetic force and the force due to the pressure anisotropy changing sign within the stellar interior. This may be an additional mechanism required for stability against cracking of the stellar object.

Generating physically realizable stellar structures via embedding

“…This feature indicates that the parameter n can be Table 2 Comparison between estimated and observed values of mass and radius for different compact stars [36] Compact star Table 3 Numerical data of AR 2 corresponding to observed mass and radius with reference to Table 1 for different values of n Compact stars n = −6.5 n = −10 n = −50 n = −500 n = −5000 n = −50,000 Table 4 Numerical data of AR 2 corresponding to observed mass and radius with reference to Table 1 for different values of n Compact stars n = −45 n = −100 n = −1000 n = −10,000 n = −100,000 viewed as a 'building' constant, that is to say, an increase in n is accompanied by an increase in mass, radius and charge which builds up the star from r = 0 through to the surface. In this work we have utilised n < 0 and the case n ≥ 0 was studied by [34]. Future work has been initiated to consider the case of general n.…”

Charged anisotropic compact objects by gravitational decoupling

“…So, the remaining constants A and a are obtained from (55) and (56), it explicitly reads However in order to close the matching conditions, the parametersM and R for strange star candidates have been used [47]. Tables 1, 2 and 3 shown all the constant parameters calculated for different values of the dimensionless coupling constant α.…”

“…So, the compactness parameter u, can be expresses in terms of the effective mass M e f f which for charged matter distribution is given by [55] M e f f = 4π…”

Anisotropic solutions by gravitational decoupling

“…Indeed, this simple and systematic method could be conveniently exploited in a large number of relevant cases, such as the Einstein-Maxwell [20] and Einstein-Klein-Gordon system [21][22][23][24], for higher derivative gravity [25][26][27], f (R)-theories of gravity [28][29][30][31][32][33][34], Hořava-aether gravity [35,36], polytropic spheres [37][38][39], among many others. In this respect, the simplest practical application of the MGD-decoupling consists in extending known isotropic and physically acceptable interior solutions for spherically symmetric self-gravitating systems into the anisotropic domain, at the same time preserving physical acceptability, which represents a highly non-trivial problem [40] (for obtaining anisotropic solutions in a generic way, see for instance Refs.…”