Ghulam Abbas2025-11-272025-11-272021https://escholar.umt.edu.pk/handle/123456789/13186In this study, the core envelope model of anisotropic spherically symmetric super dense compact star is developed. In this development, the core is expressed with a linear equation of state (EOS) and the envelope is outfitted with the generalized polytropic EOS. All the geometrical and physical variables are viable for the core and envelope of the star. The junction conditions are also satisfied for the three regions i.e. the core, envelope and the outer space. The developed model is in great agreement with the realistic stars Vela X-1, Her X-1 and SMC X-1. It is concluded that core of the star compresses as the mass increases, justifying the dominating effect of gravity of astronomical objects with greater masses.enThesis