Role of f ( T , Θ ) gravity on dynamical instability of collapsing star

In this paper, we find the instability ranges of a spherical symmetric structure of a collapsing object in $f(T,\Theta )$ theory of gravity. Here, $T$ represents the torsion scalar while $\Theta$ is the trace of energy–momentum tensor. For this purpose, we use perturbation method up to first order in the modified field equations as well as in the dynamical equations to construct a collapse equation. The collapse equation with adiabatic index $\Gamma$ is used to explore the instability ranges in Newtonian and post-Newtonian approximations. It turns out that the instability ranges depend on the dynamical variables of collapsing object.