Impact of Radial Perturbations on Expansion-free Anisotropic Fluid Spheres in D-dimensional Modified Gravity

Abstract

In this manuscript, we have continued the work of Herrera et al. (Gen. Relativ. Gravit. 44, 1143, 2012) to investigate the instability of non-static spheres supported by anisotropic matter configuration in the background of D-dimensional Einstein gravity. For this purpose, we assume that our relativistic sphere undergoes adiabatic evolution with a vanishing expansion scalar condition. We compute gravitational field equations, conservation equations, and junction conditions in D-dimensional Einstein theory. After considering the evolution of the systems under an expansion-free background, some significant constraints are established by using a perturbation scheme. This leads us to develop the dynamical instability of expansion-free anisotropic fluid spheres in the Newtonian (N) and Post-Newtonian (PN) domains. After focusing on the N and PN eras, our study reveals that the adiabatic index (\(\Gamma \)), does not contribute to the instability ranges in these domains. Instead, these ranges are being determined solely by the anisotropy of fluid pressure, D-dimensional Einstein gravity parameter, and the radial energy density profile.