Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userBehavior of anisotropic fluids with Chaplygin equation of state in Buchdahl spacetime
77
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In the present study we have proposed a new model of an anisotropic compact star which admits the Chaplygin equation of state. For this purpose, we consider Buchdahl ansatz. We obtain the solution of proposed model in closed form which is non-singular, regular and well-behaved. In addition to this, we show that the model satisfies all the energy conditions and maintains the hydrostatic equilibrium equation. This model represents compact stars like PSR B0943+10, Her X-1 and SAX J1808.4-3658 to a very good approximate.
rate research
Read More
We investigate the cosmological applications of fluids having an equation of state which is the analog to the one related to the isotropic deformation of crystalline solids, that is containing logarithmic terms of the energy density, allowing additionally for a bulk viscosity. We consider two classes of scenarios and we show that they are both capable of triggering the transition from deceleration to acceleration at late times. Furthermore, we confront the scenarios with data from Supernovae type Ia (SN Ia) and Hubble function observations, showing that the agreement is excellent. Moreover, we perform a dynamical system analysis and we show that there exist asymptotic accelerating attractors, arisen from the logarithmic terms as well as from the viscosity, which in most cases correspond to a phantom late-time evolution. Finally, for some parameter regions we obtain a nearly de Sitter late-time attractor, which is a significant capability of the scenario since the dark energy, although dynamical, stabilizes at the cosmological constant value.
In this work, we present a class of relativistic and well-behaved solution to Einsteins field equations describing anisotropic matter distribution. We perform our analysis by proposing a Buchdahl ansatz which represents almost all the known analytic solutions to the spherically symmetric, static Einstein equations with a perfect fluid source, including, in particular, the Vaidya-Tikekar. We have considered three different cases for generalized Buchdahl dimensionless parameter K. Our suggested solution is free from physical and geometric singularities, satisfies causality condition, and relativistic adiabatic index(gamma), and exhibits well-behaved nature, as well as, all energy conditions and equilibrium condition are well-defined, which implies that our model is physically acceptable.
In this paper, aniostropic dark energy cosmological models have been constructed in a Bianchi-V space-time with the energy momentum tensor consisting of two non-interacting fluids namely bulk viscous fluid and dark energy fluid. Two different models are constructed based on the power law cosmology and de Sitter universe. The constructed model also embedded with different pressure gradients along different spatial directions. The variable equation of state (EoS) parameter, skewness parameters for both the models are obtained and analyzed. The physical properties of the models obtained with the use of scale factors of power law and de Sitter law are also presented.
We study spherically symmetric geometries made of anisotropic perfect fluid based on general relativity. The purpose of the work is to find and classify black hole solutions in closed spacetime. In a general setting, we find that a static and closed space exists only when the radial pressure is negative but its size is smaller than the density. The Einstein equation is eventually casted into a first order autonomous equation on two-dimensional plane of scale-invariant variables, which are equivalent to the Tolman-Oppenheimer-Volkoff (TOV) equation in general relativity. Then, we display various solution curves numerically. An exact solution describing a black hole solution in a closed spacetime was known in Ref. [1], which solution bears a naked singularity and negative energy era. We find that the two deficits can be remedied when $rho+3p_1>0$ and $rho+p_1+2p_2< 0$, where the second violates the strong energy condition.
We attempt to study a singularity-free model for the spherically symmetric anisotropic strange stars under Einsteins general theory of relativity by exploiting the Tolman-Kuchowicz metric. Further, we have assumed that the cosmological constant $Lambda$ is a scalar variable dependent on the spatial coordinate $r$. To describe the strange star candidates we have considered that they are made of strange quark matter (SQM) distribution, which is assumed to be governed by the MIT bag equation of state. To obtain unknown constants of the stellar system we match the interior Tolman-Kuchowicz metric to the exterior modified Schwarzschild metric with the cosmological constant, at the surface of the system. Following Deb et al. we have predicted the exact values of the radii for different strange star candidates based on the observed values of the masses of the stellar objects and the chosen parametric values of the $Lambda$ as well as the bag constant $mathcal{B}$. The set of solutions satisfies all the physical requirements to represent strange stars. Interestingly, our study reveals that as the values of the $Lambda$ and $mathcal{B}$ increase the anisotropic system becomes gradually smaller in size turning the whole system into a more compact ultra-dense stellar object.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
