Existence of realistic stellar objects in Rastall gravity with linear equation of state

2020 ◽  
Vol 98 (5) ◽  
pp. 464-469
Author(s):  
M. Zubair ◽  
Maham Lodhi ◽  
G. Abbas ◽  
Mehwish Bari
Keyword(s):  
Equation Of State ◽  
Linear Equation ◽  
Anisotropy Parameter ◽  
Compact Objects ◽  
Physical Analysis ◽  
Dynamical Equations ◽  
Stellar Objects ◽  
Anisotropic Matter ◽  
Spherically Symmetric Metric ◽  
Acceptability Criteria

In this paper, we have discussed the anisotropic matter configuration to explore the existence of realistic stellar objects in non-conservative theory named as Rastall theory of gravity. We have assumed a static spherically symmetric metric with linear equation of state (EoS) to formulate the dynamical equations. The Durgapal and Banerji transformation is employed to investigate the gravitational behavior of compact objects. In this regard, a particular gravitational potential is selected to solve the system of dynamical equations numerically. We compared change in behavior of physical quantities like energy density, anisotropy parameter, and radial and tangential pressures by plotting three particular cases. With the help of physical analysis, it can be seen that the solutions of compact spheres hold physical acceptability criteria and depict stability.

Anisotropic charged realistic models in f(R) gravity under Durgapal transformation

2020 ◽  
Vol 17 (13) ◽  
pp. 2050185
Author(s):  
M. Zubair ◽  
Rabia Saleem ◽  
Maham Lodhi
Keyword(s):  
Gravitational Potential ◽  
Anisotropy Parameter ◽  
Physical Analysis ◽  
Field Equations ◽  
Stellar Objects ◽  
Anisotropic Matter ◽  
Special Cases ◽  
Charge Intensity ◽  
Acceptability Criteria ◽  
Stability And Consistency

In this paper, we investigate the charged static spherically symmetric models in [Formula: see text] theory of gravity. We consider a linear equation of state (EoS) in the background of anisotropic matter configuration. We formulate the modified field equations and implement Durgapal transformation to examine the gravitational nature of compact stellar objects. For this purpose, we choose a specific gravitational potential and electric charge intensity to analytically solve the set of field equations. We generate three special cases of solutions for specific parametric values of [Formula: see text] appearing in the expression of gravitational potential. The evolution of physical observables, such as energy density, anisotropy parameter, radial and tangential pressures and electric field intensity, are presented in all cases. Via physical analysis, it is observed that the solution of charged compact spheres satisfies acceptability criteria, models are well behaved, and depict stability and consistency in accordance with [Formula: see text] gravity for generated models.

Stability of realistic stellar objects in f(R,T) gravity with anisotropic matter configuration

2019 ◽  
Vol 16 (12) ◽  
pp. 1950191 ◽  
Author(s):  
M. Zubair ◽  
Maham Lodhi ◽  
G. Abbas
Keyword(s):  
Gravitational Potential ◽  
Compact Star ◽  
Anisotropy Parameter ◽  
Field Equations ◽  
Dynamical Equations ◽  
Anisotropic Matter ◽  
Star Models ◽  
Special Cases ◽  
Barotropic Equation ◽  
Spherically Symmetric Metric

In this paper, we have obtained a new class of solutions of modified field equations (FEqs) in [Formula: see text] gravity with barotropic equation of state (EoS) i.e. [Formula: see text]. For this purpose, we assume spherically symmetric metric with anisotropic matter distribution and formulated the FEqs. We apply Durgapal transformation and choose suitable gravitational potential to solve the dynamical equations numerically. By varying parametric values [Formula: see text] and [Formula: see text] (appearing in gravitational potential), we generate special cases of solutions. We plot physical quantities like energy density, anisotropy parameter, radial and tangential pressures in all particular cases. It is concluded that all the plots hold physical acceptability criteria and show consistency which admits modified [Formula: see text] gravity for compact star models.

scholarly journals Stability and improved physical characteristics of relativistic compact objects arising from the quadratic term in $$p_r = \alpha \rho ^2 + \beta \rho - \gamma $$

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
S. Thirukkanesh ◽  
Robert S. Bogadi ◽  
Megandhren Govender ◽  
Sibusiso Moyo
Keyword(s):  
Equation Of State ◽  
Gravitational Potential ◽  
Equations Of State ◽  
Quadratic Equation ◽  
Physical Characteristics ◽  
Compact Objects ◽  
Quadratic Term ◽  
Stellar Objects ◽  
Quadratic Equation Of State ◽  
The Stability

AbstractWe investigate the stability and enhancement of the physical characteristics of compact, relativistic objects which follow a quadratic equation of state. To achieve this, we make use of the Vaidya–Tikekar metric potential. This gravitational potential has been shown to be suitable for describing superdense stellar objects. Pressure anisotropy is also a key feature of our model and is shown to play an important role in maintaining stability. Our results show that the combination of the Vaidya–Tikekar gravitational potential used together with the quadratic equation of state provide models which are favourable. In comparison with other equations of state, we have shown that the quadratic equation of state mimics the colour-flavour-locked equation of state more closely than the linear equation of state.

Static spherically symmetric solutions in f(G) gravity

2016 ◽  
Vol 25 (07) ◽  
pp. 1650083 ◽  
Author(s):  
M. Sharif ◽  
H. Ismat Fatima
Keyword(s):  
Equation Of State ◽  
State Parameter ◽  
Energy Conditions ◽  
Conformal Killing ◽  
Spherically Symmetric ◽  
Field Equations ◽  
Anisotropic Matter ◽  
Physical Validity ◽  
Spherically Symmetric Metric ◽  
Anisotropic Case

We investigate interior solutions for static spherically symmetric metric in the background of [Formula: see text] gravity. We use the technique of conformal Killing motions to solve the field equations with both isotropic and anisotropic matter distributions. These solutions are then used to obtain density, radial and tangential pressures for power-law [Formula: see text] model. For anisotropic case, we assume a linear equation-of-state and investigate solutions for the equation-of-state parameter [Formula: see text]. We check physical validity of the solutions through energy conditions and also examine its stability. Finally, we study equilibrium configuration using Tolman–Oppenheimer–Volkoff equation.

Anisotropic solution for compact objects in f(𝒢,𝒯) gravity

2020 ◽  
Vol 35 (22) ◽  
pp. 2050121
Author(s):  
M. Sharif ◽  
Aroob Naeem
Keyword(s):  
Compact Star ◽  
Compact Objects ◽  
Anisotropic Solution ◽  
Stellar Objects ◽  
Energy Bounds ◽  
Compactness Factor ◽  
Celestial Bodies ◽  
Specific Formula ◽  
The Stability ◽  
Spherically Symmetric Metric

In this paper, we consider a new solution to discuss the physical aspects of anisotropic compact celestial bodies in the background of [Formula: see text] theory. We take static spherically symmetric metric to describe the internal region of the stellar objects and apply the embedding class-I method to get the metric solution corresponding to a specific [Formula: see text] model. By matching the interior and exterior geometries at the boundary, we find the values of unknown constants. We check the stability and viability of the resulting solution through various parameters that include energy bounds, causality condition, Herrera’s condition, role of adiabatic index, redshift and compactness factor. The graphical interpretation is done for some particular compact star candidates, i.e. LMC X-4, Cen X-3, 4U 1820-30 and Vela X-1. We conclude that our model provides physically acceptable structure of the considered compact objects and is also stable.

scholarly journals Mass-radius relation of compact objects

2019 ◽  
Vol 15 (S356) ◽  
pp. 383-384
Author(s):  
Seman Abaraya ◽  
Tolu Biressa
Keyword(s):  
Numerical Analysis ◽  
Equation Of State ◽  
Compact Objects ◽  
Mass Limit ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Formation And Evolution ◽  
Active Research ◽  
Compact Sources ◽  
Astrophysical Research

AbstractCompact objects are of great interest in astrophysical research. There are active research interests in understanding better various aspects of formation and evolution of these objects. In this paper we addressed some problems related to the compact objects mass limit. We employed Einstein field equations (EFEs) to derive the equation of state (EoS). With the assumption of high densities and low temperature of compact sources, the derived equation of state is reduced to polytropic kind. Studying the polytropic equations we obtained similar physical implications, in agreement to previous works. Using the latest version of Mathematica-11 in our numerical analysis, we also obtained similar results except slight differences in accuracy.

scholarly journals Classification of Compact Objects: QSS, QSOs, N-Type and Compact Galaxies, Seyfert and Galactic Nuclei

1972 ◽  
Vol 44 ◽  
pp. 97-103
Author(s):  
W. W. Morgan
Keyword(s):  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Classification Criteria ◽  
Compact Objects ◽  
Stellar Objects ◽  
Quasi Stellar Objects ◽  
Compact Galaxies

Some methods currently in use for the classification of the optical forms of the ‘compact’ galaxies and quasi-stellar objects are reviewed. It is shown that the category ‘Seyfert Galaxy’ is basically a spectroscopic (rather than a form) classification.An optical form-classification is described which is, in principle, identical with published classification criteria for QSO, N-type, and compact objects. The importance of maintaining rigid form-standards is emphasized.

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