Narrow Results

The main purpose of this study is to explore various essential features of compact star configurations in the context of modified $f(R)$ gravity using Krori–Barua (KB) spacetime. It is notable to say that we employ the exponential type $f(R,\varphi )$ gravity model to illustrate the entire set of a modified system of field equations. Further, we form the field equations for a spherically symmetric line element with an anisotropic matter source via KB metric potentials. We postulate the distinct stellar objects to obtain the values of the unknown parameters. Moreover, we accomplish various physical properties, such as the behavior of energy density and pressure evolution, mass and compactness functions, anisotropy, equilibrium conditions, and energy bonds, to appraise the consistency and reliability of our chosen model. It is shown that investigated stellar structure solutions confirm a steady consistency for anisotropic exponential spheres with KB metric potentials in Modified $f(R,\varphi )$ Gravity.

We discuss the existence of compact stars in the context of $f(R)=R+\alpha R^2+\beta R^{2}ln(\beta R)$ gravity model, where additional logarithmic corrections are assumed. Here, $R$ is the Ricci scalar and $\alpha$, $\beta$ are constant values. Further, the compact stars are considered to be anisotropic in nature, due to the spherical symmetry and high density. For this purpose, we derive the Einstein field equations by considering Krori–Barua spacetime. For our proposed model, the physical acceptability is verified by employing several physical tests like the energy conditions, Herrera cracking concept and stability condition. In addition to this, we also discuss some important properties such as mass–radius relation, surface redshift and the speed of sound are analyzed. Our results are compared with observational stellar mass data, namely, 4U 1820-30, Cen X-3, EXO 1785-248 and LMC X-4. The graphical representation of obtained solutions provide strong evidences for more realistic and viable stellar model.

We consider $R^2$ corrected model, i.e. $f(R)=R+\alpha R^2+\beta R^{2}ln(\beta R)$, where $R$ is the Ricci scalar and $\alpha$, $\beta$ are arbitrary constant values, to investigate some of the interior configurations of static anisotropic spherical charged stellar structures. The existence of electric charge and a strong electric field confirms due to the higher values of pressure distribution and energy density of the matter inside the stars. Furthermore, for compact star configurations, we also consider the simplified MIT bag model equation of state (EoS) given by $p_r=\frac{1}{3}(\rho -4B)$, where $p_r$ is radial pressure, $\rho$ is energy density and $B$ is bag constant. This approach allows to find electric charge from the Einstein–Maxwell field equations. We have extensively discussed the behavior of the electric charge and anisotropic fluid distribution factor for five different values of $\beta$. Interestingly, it is noticed during this study, for smaller values of $\beta$ we get intensity in electric charge. The Tolman–Oppenheimer–Volkoff equation (TOV), is modified in order to carry electric charge. In particular, we model the compact star candidates SAXJ 1808.4–3658 and Vela X-1 and give graphical representation of some important properties such as equilibrium condition, mass-radius ratio and surface redshift. In the end, our calculated solutions provide strong evidences for more realistic and viable charged stellar model.

This study is devoted to investigate the formation of compact stars using Tolman–Kuchowicz space-time in $f({𝒢},{𝒯})$ gravity. By taking into account the physically reliable formulations of metric potentials, $\xi$ = $B{r}^2+2\mathrm{\text{ln}}C$ and $\eta$ = $\mathrm{\text{ln}}(1+a{r}^2+b{r}^4)$, we investigate the equation of motion for spherically symmetric space-time in the presence of an anisotropic matter distribution. Furthermore, matching conditions are employed to compute the unknown constants. By making use of dynamical equations, the pivotal relevant aspects, including energy density, radial and tangential pressures, dynamical equilibrium, anisotropy effect, energy conditions and stability, are physically tested in order to determine the physical acceptability of yielding celestial model, which are thoroughly compared with experimental facts and figures of ten different compact stars. Finally, we observe that obtained anisotropic outcomes are physically viable, free from geometrical and physical singularities. Moreover, these outcomes also provide circumstantial evidence for the existence of super-massive compact stars.

This paper investigated the anisotropic quintessence stars in the $f(R,\varphi )$ theory of gravity, where $R$ is the Ricci scalar and $\varphi$ is the scalar potential. We investigated the field equations of the $f(R,\varphi )$ theory of gravity by using the Krori–Barua technique. We have determined that all the obtained solutions are free from central singularity and potentially stable. The observed values of mass and radius of the different strange stars Her X1, SAXJ1808.4-3658, and 4U1820-30 have been used to calculate the values of unknown constants in the Krori and Barua metric. The physical phenomena of stars, such as energy density, pressure components, anisotropy, sound speeds, equation of state parameters, energy conditions and redshift have been investigated in detail.

This paper examines the viable characteristics of anisotropic compact stars in $f(\Re ,T^2)$ theory ($\Re$ is the Ricci scalar and $T^2=T_{\alpha \beta }{T}^{\alpha \beta }$). In this perspective, we use Tolman–Kuchowicz solutions $(\mu =w{r}^2+2lnz$ and $\nu =ln(1+x{r}^2+y{r}^4))$ to examine the configurations of static spherically symmetric structures. The unknown constants are found by the first fundamental form of Darmois junction conditions. We analyze the behavior of fluid parameters in the interior of 4U 1538-52, PSRJ 1614-220, EXO 1785-248 and SAXJ 1808.4-3658 compact stars correspond to different models of this theory. Furthermore, the stability of the proposed compact stellar objects is examined through sound speed and adiabatic index methods. The satisfaction of requisite conditions ensures that stable compact objects exist in this framework.