Evolution of anisotropic and charged neutron stars in the lower mass gap with a perturbative approach in f(T,τ) gravity: Constraining the equation of state and physical properties in the light of NICER observations

This recent study is concerned with deriving the mass-radius relation based on the modification of the Tolman–Oppenheimer–Volkoff equation for anisotropic Neutron Star systems within the modified [Formula: see text] gravity. We have incorporated the perturbative approach here and [Formula: see text] modified gravity has been considered under a static spherically symmetric spacetime. The modified [Formula: see text] gravity is chosen in the form as [Formula: see text], where [Formula: see text] is a small parameter, [Formula: see text] is an arbitrary function of the torsion scalar T and the trace [Formula: see text] of the energy–momentum tensor given by [Formula: see text]. Additionally, we have enforced the modified Chaplygin gas equation of state of the Neutron Stars on the derived equations to obtain the mass-radius profile and mass-central density relations of the anisotropic Neutron Stars in [Formula: see text] modified gravity. Further, the impact of charge and anisotropy on the structural features and in equilibrium configuration of those compact objects has also been investigated rigorously.