Charged anisotropic superdense stars with constant stability factor

Abstract

In this paper, we have presented charged anisotropic Vlasenko-Pronin solutions and a new charged anisotropic Schwarzschild interior solution of the general relativistic field equations in curvature coordinates. These exact solutions are stable and well behaved in all respects for a wide range of anisotropy parameter and charge parameter. These new solutions can be used to model charged, anisotropic neutron stars and quark stars whose masses are comparatively heavier. An interesting fact of these solutions is that their stability factors $|v^{2}_{\perp}-v^{2}_{r}|<1$ are constants. Also, we have presented a new and first solution where radial pressure is greater than transverse pressure (i.e. $p_{r}-p_{\perp}>0$). For a neutral solution it reduces to the Schwarzschild interior solution with constant density. Our charged analogue of the Schwarzschild solution has density decreasing outward to the surface of the star which is necessary for a physical star. The EOSs corresponding to the presented solutions are also studied with their stiffness or softness by comparing their compression moduli. Furthermore, these compression moduli are decreasing outwards from the center. We expect this as the core must be very compact compared to its surface.