Browsing by Author "Maharaj, Sunil D"

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    Charged anisotropic model with embedding and a linear equation of state
    (Springer, 2023) Mathias, Alberto K; Sunzu, Jefta M; Maharaj, Sunil D; Mkenyeleye, Jason M
    Exact solutions to the Einstein field equations for charged relativistic anisotropic stars are generated. The Karmarkar condition is used with the Einstein–Maxwell field equations and a linear equation of state to investigate various physical properties and behaviour of the compact star. The nonlinear differential equations and the field equations are transformed by adopting the Bannerji and Durgapal transformation. The embedding approach provides a relationship between gravitational potentials that help to solve and integrate the field equations. This enables one to specify one of the gravitational potentials, measure of anisotropy or electric field on a physical basis. In particular, the model is generated using embedding with a linear equation of state. The detailed physical analysis of the results show that the gravitational potentials and matter variables are well behaved. The model satisfies all the necessary physical conditions, such as stability, equilibrium, energy conditions and the mass–radius relationship.
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    Three-layered star comprising polytropic, quark and gaseous matter
    (Springer, 2022) Lighuda, Avirt S; Maharaj, Sunil D; Sunzu, Jefta M; Mureithi, Eunice W
    We construct a new exact model for a dense stellar object utilising the Einstein–Maxwell system of equations. The model comprises three interior regions with distinct equations of state (EoS): the polytropic EoS at the core region, linear EoS at the intermediate region and Chaplygin EoS at the envelope region. Our model can regain earlier solutions. A physical analysis reveals that the matter variables, metric functions and other physical conditions are well behaved and consistent in the study of dense stellar objects. Matching of the boundary layers is done with help of the Reissner–Nordstrom exterior space–time. An interesting feature is that the innermost region is outfitted with a polytropic EoS, and this study extends a core–envelope model developed by Mardan, Noureen and Khalid into a three-layered mode