Browsing by Author "Mkenyeleye, Jason M."
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Item Charged anisotropic composite stellar object with strange, polytropic and gaseous matter(Elsevier, 2024-08) Olengeile, Lilian; Sunzu, Jefta M.; Mkenyeleye, Jason M.In this study, we build a charged star model with three layers with distinct equations of state. The core, intermediate layer, and envelope layer obey linear, polytropic, and Chaplygin equations of state, respectively. The model satisfies the physical requirements for the matter variables, gravitational potentials, and stability conditions. We have generated within-acceptable range masses and radii for stars. We also recover the masses and radii for the stars PSRJ1903+0327, PSRJ1614-2230, SAXJ1808.4-3658, Vela X-1, and EXO1785-248 from earlier investigations which shows astrophysical significance of our model.Item Charged anisotropic models via embedding(Springer, 2021) Mathias, Alberto K.; Maharaj, Sunil D.; Sunzu, Jefta M.; Mkenyeleye, Jason M.We generate exact solutions to the Einstein–Maxwell field equations by analysing the embedding condition. We obtain a relationship between gravitational potentials that helps to solve the embedding condition and integrate the field equations. Our choice of the measure of anisotropy and electric field are physically realistic. Our model contains several previously known solutions as special cases. These include the investigations of interior Schwarzchild metric, Finch and Skea, Hansraj and Maharaj, Feroze and Siddiqui, and Manjonjo, Maharaj and Moopanar. We also describe the structure and properties of the relativistic star by including graphical representations. Our analysis shows that the body is stable, all energy conditions are satisfied, the regularity condition is not violated, forces under equilibrium condition are balanced, all matter variables are well behaved and the matching conditions are satisfied at the boundary of the relativistic star.Item Core-envelope anisotropic star model admitting Karmarkar condition(Elsevier BV, 2024) Mathias, Amos V.; Sunzu, Jefta M.; Mkenyeleye, Jason M.We generate a neutral core-envelope stellar model with anisotropic fluid distribution which admits Karmarkar condition. The core and envelope layers are assumed to compose quark matter and neutron fluid consistent with linear and quadratic equations of state, respectively. The results obtained indicate that the present model conforms with physical and stability tests. In the present model we have generated radii and masses of astrophysical objects consistent with observations such as HerX-1, 4U 1538-52 and SAX J1808.4-3658. It is interesting to note that the study of multilayered stars in Karmarkar condition is missing in the stellar models generated in the past.Item Physical quark star model with generalized logarithmic anisotropy(World Scientific Pub Co Pte Ltd, 2023) Mkenyeleye, Jason M.; Juma, Mahamudu; Sunzu, Jefta M.A new quark star model for a charged anisotropic stellar object is generated using the Einstein–Maxwell field equations. We use a metric function, linear equation of state, and a new measure of anisotropy in form of logarithmic function to formulate the model. For particular choices of parameters in the anisotropic measure, some anisotropic and isotropic models are regained as a special case. Physical analysis indicates that matter variables and gravitational potentials in the model are well behaved. The generated model satisfies the energy, regularity, causality, and stability conditions. The speed of sound is consistent with quark stars.Item Quark star models with logarithmic anisotropy(Springer, 2022) Juma, Mahamudu; Mkenyeleye, Jason M.; Sunzu, Jefta M.New models for the charged anisotropic stellar object were generated using the Einstein–Maxwell field equations. A new choice of pressure anisotropy in logarithmic form was used to generate a quark star model. Anisotropic and isotropic models were regained as a special case. We regained anisotropic models found by Maharaj, Sunzu and Ray; Abdalla, Sunzu and Mkenyeleye; and Sunzu and Danford. The isotropic models regained include the performance by Mak and Harko, and Maharaj and Komathiraj. Physical analysis showed that matter variables and the gravitational potentials are well behaved. Our model does satisfy the energy conditions and stability condition.