We propose a new model of dark energy star consisting of five zones, namely, the solid core of constant energy density, the thin shell between core and interior, an inhomogeneous interior region with anisotropic pressures, a thin shell, and the exterior vacuum region. We discuss various physical properties. The model satisfies all the physical requirements. The stability condition under a small linear perturbation is also discussed.

This article was published in the Astrophysics and Space Science [© 2015, Springer Science+Business Media Dordrecht] and the definite version is available at : http://dx.doi.org/10.1007/s10509-015-2462-9. The Journal's website is at: http://link.springer.com/article/10.1007%2Fs10509-015-2462-9In this paper we have studied the behavior of static spherically symmetric relativistic objects with locally anisotropic matter distribution considering the Tolman VII form for the gravitational potential grr in curvature coordinates together with the linear relation between the energy density and the radial pressure. The interior spacetime has been matched continuously to the exterior Schwarzschild geometry. We have investigated and analyzed different physical properties of the stellar model and presented graphically.Publishe

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We provide a new class of interior solutions for anisotropic stars admitting conformal motion in higherdimensional noncommutative spacetime. The Einstein field equations are solved by choosing a particular density distribution function of Lorentzian type as provided by Nazari and Mehdipour [1,2] under a noncommutative geometry. Several cases with 4 and higher dimensions, e.g. 5, 6, and 11 dimensions, are discussed separately. An overall observation is that the model parameters, such as density, radial pressure, transverse pressure, and anisotropy, all are well behaved and represent a compact star with mass 2.27 M and radius 4.17 km. However, emphasis is put on the acceptability of the model from a physical point of view. As a consequence it is observed that higher dimensions, i.e. beyond 4D spacetime, exhibit several interesting yet bizarre features, which are not at all untenable for a compact stellar model of strange quark type; thus this dictates the possibility of its extra-dimensional existence.

Present paper provides a new model of anisotropic strange star corresponding to the exterior schwarzschild metric.The Einstein field equations have been solved by utilizing the Krori-Barua (KB) ansatz [K.D. Krori and J. Barua, J. Phys. A: Math. Gen. 8, 508 (1975)] in presence of quintessence field characterized by a parameter ω q with −1 < ω q < − 1 3 .The obtained solutions are free from central singularity. Our model is potentially stable.The numerical values of mass of the different strange stars SAXJ1808.4-3658(SS1)(radius=7.07 km),4U1820-30 (radius=10 km),Vela X-12 (radius=9.99 km),PSR J 1614-2230 (radius=10.3 km) obtained from our model is very close to the observational data that confirms the validity of our proposed model. The interior solution is also matched to the exterior Schwarzschild spacetime in presence of thin shell where negative surface pressure is required to hold the thin shell against collapse.

In the present article, we have constructed static anisotropic compact star models of Einstein field equations for the spherical symmetric metric of embedding class one. By assuming the particular form of metric function ν, We have solved the Einstein field equations for anisotropic matter distribution. The anisotropic models are representing the realistic compact objects such as SAX J 1808.4-3658 (SS1), Her X -1, Vela X-12, PSR J1614-2230 and Cen X -3. We have reported our results in details for compact star Her X-1 on the ground of physical properties such as pressure, density, velocity of sound, energy conditions, TOV equation and red-shift etc. Along with these, we have also discussed about stability of the compact star models. Finally we made the comparison between our anisotropic stars with the realistic objects on the key aspects as central density, central pressure, compactness and surface red-shift.

In the present paper we have constructed a new relativistic anisotropic compact star model having a spherically symmetric metric of embedding class one. Here we have assumed an arbitrary form of metric function e λ and solved the Einstein's relativistic field equations with the help of Karmarkar condition for an anisotropic matter distribution. The physical properties of our model such as pressure, density, mass function, surface red-shift, gravitational red-shift are investigated and the stability of the stellar configuration is discussed in details. Our model is free from central singularities and satisfies all energy conditions. The model we present here satisfy the static stability criterion i.e. dM/dρc > 0 for 0 ≤ ρc ≤ 4.04 × 10 17 g/cm 3 (stable region) and for ρc ≥ 4.04 × 10 17 g/cm 3 , the region is unstable i.e., dM/dρc ≤ 0.

In this paper we utilise the Krori-Barua ansatz to model compact stars within the framework of EinsteinGauss-Bonnet (EGB) gravity. The thrust of our investigation is to carry out a comparative analysis of the physical properties of our models in EGB and classical general relativity theory with the help of graphical representation. From our analysis we have shown that the central density and central pressure of EGB star model is higher than the GTR star model. The most notable feature is that for both GTR and the EGB star model the compactness factor crosses the Buchdahl (Phys Rev 116:1027, 1959) limit.