2021RAA....21..162B

In this work, we present a cogent and physically well-behaved solution for neutron stars envisaged with a core layer having quark matter satisfying the MIT-bag equation of state (EoS), meso layer with Bose-Einstein condensate (BEC) matter satisfying modified BEC EoS and an envelope having neutron fluid and Coulomb liquids satisfying quadratic EoS. All the required physical and geometrical parameters like gravitational potentials, pressures, radial velocity, anisotropy, adiabatic index, mass function, compactification factor, and gravitational and surface redshift functions show a feasible trend and are continuous with smooth variation throughout the interior and across the regions of the star. Further, causality condition, energy conditions, static stability criterion (using Tolman-Oppenheimer-Volkoff equation) and Herrera cracking stability criterion are met throughout the star. The approach seems to be resulting in more realistic and accurate modeling of stellar objects, particularly realized by us for X-ray binary stars 4U 1608-52 (M = 1.7 M☉, R = 9.5 km) and SAX J1808.4-3658 (M = 1.2 M☉, R = 7.2 km). Furthermore, we have ascertained that the continuity of the stability factor in all three regions of the stars demand a smaller core. As the core region of the star increases, the stability factor becomes discontinuous at all the interfaces inside the star.