Strange stars with MIT bag model in the Rastall theory of gravity

2019 ◽  
Vol 16 (09) ◽  
pp. 1950132 ◽  
Author(s):  
M. R. Shahzad ◽  
G. Abbas
Keyword(s):  
Dimensionless Parameter ◽  
Energy Conditions ◽  
Field Equations ◽  
Bag Model ◽  
Strange Stars ◽  
Physical Conditions ◽  
Mit Bag Model ◽  
Reasonable Solution ◽  
Physical Features ◽  
Anisotropic Source

The aim of this paper is to study the charged anisotropic strange stars in the Rastall framework. Basic formulation of field equations in this framework is presented in the presence of charged anisotropic source. To obtain the solutions of the Rastall field equations in spherically symmetric Karori and Barua (KB) type space-time, we have considered a linear equation of state of strange matter, using the MIT bag model. The constraints on the Rastall dimensionless parameter [Formula: see text] are also discussed to obtain the physically reasonable solution. We explore some physical features of the presented model like energy conditions, stability and hydrostatic equilibrium, which are necessary to check the physical viability of the model. We also sought for the influence of the Rastall dimensionless parameter on the behavior of the physical features of obtained solution. We plot the graphs of matter variables for different chosen values of the parameter [Formula: see text] to inspect more details of analytical investigations and predict the numerical values of these variables exhibited in the tabular form. For this analysis, we choose four different arbitrary models of strange stars with compactness [Formula: see text] 0.25, 0.30, 0.35 and 0.40. We observed that all the necessary physical conditions are satisfied and the presented model is quite reasonable to study the strange stars.

Study of tilted cylindrical quark star

2020 ◽  
Vol 35 (14) ◽  
pp. 2050110
Author(s):  
M. Sharif ◽  
Sumaira Nazir
Keyword(s):  
Numerical Solution ◽  
Energy Conditions ◽  
Fluid Distribution ◽  
Quark Star ◽  
Field Equations ◽  
Dynamical Equations ◽  
Stellar Matter ◽  
Mit Bag Model ◽  
Pressure Anisotropy ◽  
Physical Features

In this paper, we study perfect, anisotropic and anisotropic dissipative cylindrical quark star for the tilted observer. To this end, the field equations and dynamical equations are formulated and assume MIT bag model to find a numerical solution of the field equations. The behavior of resulting model is investigated by plotting density, pressure, anisotropy and energy conditions. We check viability of the solutions through physical features related to stellar matter configuration. Finally, we discuss stability for all the cases of fluid distribution.

scholarly journals Compact stars in f(ℛ,𝒢,𝒯 ) gravity

2021 ◽  
Vol 36 (24) ◽  
pp. 2150165
Author(s):  
M. Ilyas
Keyword(s):  
Test Particle ◽  
Gravitational Theory ◽  
Momentum Tensor ◽  
Conservation Equation ◽  
Compact Objects ◽  
Compact Stars ◽  
Energy Conditions ◽  
Field Equations ◽  
Physical Features ◽  
The Impact

This work is to introduce a new kind of modified gravitational theory, named as [Formula: see text] (also [Formula: see text]) gravity, where [Formula: see text] is the Ricci scalar, [Formula: see text] is Gauss–Bonnet invariant and [Formula: see text] is the trace of the energy–momentum tensor. With the help of different models in this gravity, we investigate some physical features of different relativistic compact stars. For this purpose, we develop the effectively modified field equations, conservation equation, and the equation of motion for test particle. Then, we check the impact of additional force (massive test particle followed by a nongeodesic line of geometry) on compact objects. Furthermore, we took three notable stars named as [Formula: see text], [Formula: see text] and [Formula: see text]. The physical behavior of the energy density, anisotropic pressures, different energy conditions, stability, anisotropy, and the equilibrium scenario of these strange compact stars are analyzed through various plots. Finally, we conclude that the energy conditions hold, and the core of these stars is so dense.

Study of some compact objects in R + 2βT gravity

2019 ◽  
Vol 28 (16) ◽  
pp. 2040005
Author(s):  
Arfa Waseem ◽  
M. Sharif
Keyword(s):  
Stellar System ◽  
Graphical Analysis ◽  
Compact Objects ◽  
Stellar Structure ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Field Equations ◽  
Star Models ◽  
Mit Bag Model ◽  
Text Model

The aim of this work is to examine the nature as well as physical characteristics of anisotropic spherically symmetric stellar candidates in the context of [Formula: see text] gravity. We assume that the fluid components such as pressure and energy density are related through MIT bag model equation-of-state in the interior of stellar system. In order to analyze the structure formation of some specific star models, the field equations are constructed using Krori–Barua solution in which the unknown constants are evaluated by employing observed values of radii and masses of the considered stars. We check the consistency of [Formula: see text] model through the graphical analysis of energy conditions as well as stability of stellar structure. It is found that our considered stars show viable as well as stable behavior for this model.

scholarly journals Anisotropic strange star inspired by Finsler geometry

2020 ◽  
Vol 29 (01) ◽  
pp. 2050001 ◽  
Author(s):  
Sourav Roy Chowdhury ◽  
Debabrata Deb ◽  
Farook Rahaman ◽  
Saibal Ray ◽  
B. K. Guha
Keyword(s):  
Finsler Geometry ◽  
Stellar System ◽  
Main Idea ◽  
Quark Distribution ◽  
Energy Conditions ◽  
Field Equations ◽  
Strange Stars ◽  
Respective Field ◽  
The Stability ◽  
Stellar Configuration

In this paper, we report on a study of the anisotropic strange stars under Finsler geometry. Keeping in mind that Finsler spacetime is not merely a generalization of Riemannian geometry rather the main idea is the projectivized tangent bundle of the manifold [Formula: see text], we have developed the respective field equations. Thereafter, we consider the strange quark distribution inside the stellar system followed by the MIT bag model equation-of-state (EoS). To find out the stability and also the physical acceptability of the stellar configuration, we perform in detail some basic physical tests of the proposed model. The results of the testing show that the system is consistent with the Tolman–Oppenheimer–Volkoff (TOV) equation, Herrera cracking concept, different energy conditions and adiabatic index. One important result that we observe is, the anisotropic stress reaches the maximum at the surface of the stellar configuration. We calculate (i) the maximum mass as well as the corresponding radius, (ii) the central density of the strange stars for finite values of bag constant [Formula: see text] and (iii) the fractional binding energy of the system. This study shows that Finsler geometry is especially suitable to explain massive stellar systems.

Gravitationally decoupled non-static anisotropic spherical solutions

2021 ◽  
pp. 2150145
Author(s):  
M. Sharif ◽  
Shehrbano Ahmed
Keyword(s):  
Energy Conditions ◽  
Matter Distribution ◽  
Field Equations ◽  
Anisotropic Models ◽  
Geometric Deformation ◽  
Gravitational Source ◽  
Barotropic Equation ◽  
Gravitating Systems ◽  
Deformation Approach ◽  
Anisotropic Source

This paper is devoted for the formulation of new anisotropic solutions for non-static spherically symmetric self-gravitating systems through gravitational decoupling technique. Initially, we add a gravitational source in the perfect matter distribution for inducing the effects of anisotropy in the considered model. We then decouple the field equations through minimal geometric deformation approach and derive three new anisotropic solutions. Among these, two anisotropic solutions are evaluated by applying specific constraints on anisotropic source and the third solution is obtained by employing the barotropic equation of state. The physical acceptability and stability of the anisotropic models are investigated through energy conditions and causality condition, respectively. We conclude that all the derived anisotropic solutions are physically viable as well as stable.

scholarly journals Decoupled Embedding Class-One Strange Stars in Self-Interacting Brans–Dicke Gravity

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 161
Author(s):  
Muhammad Sharif ◽  
Amal Majid
Keyword(s):  
Fluid Distribution ◽  
Quark Star ◽  
Field Equations ◽  
Additional Source ◽  
Massive Scalar Field ◽  
Star Models ◽  
Embedding Class One ◽  
Mit Bag Model ◽  
Embedding Condition ◽  
Anisotropic Source

This work aims to extend two isotropic solutions to the anisotropic domain by decoupling the field equations in self-interacting Brans–Dicke theory. The extended solutions are obtained by incorporating an additional source in the isotropic fluid distribution. We deform the radial metric potential to disintegrate the system of field equations into two sets such that each set corresponds to only one source (either isotropic or additional). The system related to the anisotropic source is solved by employing the MIT bag model as an equation of state. Further, we develop two isotropic solutions by plugging well-behaved radial metric potentials in Karmarkar’s embedding condition. The junction conditions at the surface of the star are imposed to specify the unknown constants appearing in the solution. We examine different physical characteristics of the constructed quark star models by using the mass and radius of PSR J1903+327. It is concluded that, in the presence of a massive scalar field, both stellar structures are well-behaved, viable and stable for smaller values of the decoupling parameter.

Modeling of immense gravity objects via generalized solution of Einstein’s field equations

2019 ◽  
Vol 28 (10) ◽  
pp. 1950134
Author(s):  
Kiran Pant ◽  
Pratibha Fuloria
Keyword(s):  
Mass Formula ◽  
Compact Star ◽  
Generalized Solution ◽  
Energy Conditions ◽  
Anisotropic Fluid ◽  
Field Equations ◽  
Star Models ◽  
Spacetime Manifold ◽  
Class 1 ◽  
Physical Features

In this paper, we generate a new generalized solution for modeling of compact anisotropic astrophysical configurations by using Karmarkar condition of embedded class 1 spacetime manifold. We demonstrate that the new solution satisfies all required physical conditions. We investigate several physical properties of compact star models, i.e. Vela X-1 (Mass [Formula: see text][Formula: see text], radius = [Formula: see text][Formula: see text]km), PSRJ [Formula: see text] (Mass [Formula: see text][Formula: see text], radius = [Formula: see text][Formula: see text]km) and PSRJ [Formula: see text] (Mass [Formula: see text][Formula: see text], radius = [Formula: see text][Formula: see text]km) in conformity with the observational data. The proposed solution is free from singularities, satisfies causality condition and displays well-behaved nature inside the anisotropic configurations. All energy conditions and hydrostatic equilibrium condition are well defined inside the anisotropic fluid spheres. The adiabatic index throughout the stellar interior is greater than [Formula: see text] and the compactification factor lies within the Buchdahl limit [Formula: see text]. We study the physical features of the solution in detail, analytically as well as graphically for compact star Vela X-1 with [Formula: see text] ranging from [Formula: see text] to [Formula: see text].

THE PROPERTIES OF STRANGE STARS IN THE QUARK MASS– DENSITY–DEPENDENT MODEL

1998 ◽  
Vol 07 (01) ◽  
pp. 29-48 ◽  
Author(s):  
O. G. BENVENUTO ◽  
G. LUGONES
Keyword(s):  
Equation Of State ◽  
Quark Mass ◽  
Mass Density ◽  
Baryon Number ◽  
Moment Of Inertia ◽  
Bag Model ◽  
Strange Stars ◽  
Strange Matter ◽  
Mit Bag Model ◽  
Dependent Model

We study the general properties of compact objects made up of strange matter in the framework of a new equation of state in which the quark masses are parametrized as functions of the baryon density, so that they are heavy (light) at low (high) densities. This has been called the "quark mass-density-dependent model." In this approximation, the strange matter equation of state is rather similar to the corresponding to the MIT Bag Model, but it is significantly stiffer at low densities. Such a property modifies the structure of strange stars in a sizeable way. In this framework, we calculate the structure of strange stars (mass, radius, central density, gravitational redshift, moment of inertia, and total baryon number) finding that the resulting structures are rather similar to those obtained in the MIT Bag model, although some important differences appear. Comparing to the standard bagged case (with a bag constant in the range of B = 60 - 80 MeV fm-3), we find that these objects may be more massive and may show gravitational redshifts larger (up to ≈ 10%) than in the bag case. The moment of inertia and total baryon number may be larger than in the bagged case up to a factor of three. We also calculate the first three radial pulsation modes of these objects, finding that the relation of period vs. gravitational redshift is rather similar to the bag case. Also, we present an analytical treatment for such modes in the low-mass strange stars regime, which is in reasonable agreement with the numerical results.

scholarly journals Study on Anisotropic Strange Stars in f ( T , T ) Gravity

Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 167
Author(s):  
Ines G. Salako ◽  
M. Khlopov ◽  
Saibal Ray ◽  
M. Z. Arouko ◽  
Pameli Saha ◽  
...  
Keyword(s):  
Energy Momentum Tensor ◽  
Torsion Tensor ◽  
Equations Of Motion ◽  
Momentum Tensor ◽  
Compact Objects ◽  
Energy Conditions ◽  
Anisotropic Pressure ◽  
Strange Stars ◽  
Spacetime Geometry ◽  
Physical Features

In this work, we study the existence of strange stars in the background of f(T,T) gravity in the Einstein spacetime geometry, where T is the torsion tensor and T is the trace of the energy-momentum tensor. The equations of motion are derived for anisotropic pressure within the spherically symmetric strange star. We explore the physical features like energy conditions, mass-radius relations, modified Tolman–Oppenheimer–Volkoff (TOV) equations, principal of causality, adiabatic index, redshift and stability analysis of our model. These features are realistic and appealing to further investigation of properties of compact objects in f(T,T) gravity as well as their observational signatures.

scholarly journals Strange Star Equations of State Revisited

2005 ◽  
Vol 22 (4) ◽  
pp. 292-297 ◽  
Author(s):  
Debora P. Menezes ◽  
Don B. Melrose
Keyword(s):  
Neutron Stars ◽  
Quark Matter ◽  
Equations Of State ◽  
Bag Model ◽  
Strange Stars ◽  
Strange Matter ◽  
Strong Force ◽  
Mit Bag Model ◽  
Central Energy ◽  
Weakly Dependent

AbstractMotivated by recent suggestions that strange stars can be responsible for glitches and other observational features of pulsars, we review some possible equations of state and their implications for models of neutron, hybrid, and strange stars. We consider the MIT bag model and also strange matter in the colour–flavour locked phase. The central energy densities for strange stars are higher than the central densities of ordinary neutron stars. Strange stars are bound by the strong force and so can also rotate much faster than neutron stars. These results are only weakly dependent on the model used for the quark matter. If just one of the existing mass-to-radius ratio constraint is valid, most neutron stars equations of state are ruled out, but all the strange stars equations of state presented in this work remain consistent with the constraint.

Sign in / Sign up

Export Citation Format

Share Document