Dynamical Instability of Expansion-Free Collapse in f(T) Gravity

Abstract

In this paper, we analyze the dynamical instability of a spherically symmetric collapsing star in the context of f(T) gravity. For this purpose, we assume power-law f(T) model with non-dissipative anisotropic fluid distribution under expansion-free condition. The perturbation scheme is applied to all matter, metric and f(T) functions. We formulate dynamical equations using contracted Bianchi identities to investigate dynamical instability ranges in Newtonian and post-Newtonian regimes. It is found that the instability ranges of expansion-free fluid are independent of adiabatic index but depend on radial density profile, anisotropic pressure and torsion terms.