Browsing by Author "Mathias, Amos V."

Now showing 1 - 3 of 3
  • Thumbnail Image
    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.
  • Thumbnail Image
    Item
    Regular quark star model with pressure anisotropy
    (Springer, 2022) Mathias, Amos V.; Sunzu, Jefta M.
    A new regular model for a stellar sphere with quark matter is found. The model satisfies a neutral quark star with pressure anisotropy. In this model, we consider an ansatz of a new form of one of the gravitational potentials, and stellar masses consistent with other findings which describe the generation of astrophysical objects. New masses, radii and surface gravitational red-shifts in acceptable ranges are also obtained using our model. The model satisfies stability and energy conditions. The state of hydrostatic equilibrium for stability is obtained by analysing the Tolman–Oppenheimer–Volkoff (TOV) equation. All other matter variables and gravitational potentials are well behaved.
  • Thumbnail Image
    Item
    A well-behaved anisotropic strange star model
    (Hindawi, 2022) Mathias, Amos V.; Sunzu, Jefta M.
    We obtain a new nonsingular exact model for compact stellar objects by using the Einstein field equations. The model is consistent with stellar star with anisotropic quark matter in the absence of electric field. Our treatment considers spacetime geometry which is static and spherically symmetric. Ansatz of a rational form of one of the gravitational potentials is made to generate physically admissible results. The balance of gravitational, hydrostatic, and anisotropic forces within the stellar star is tested by analysing the Tolman-Oppenheimer-Volkoff (TOV) equation. Several stellar objects with masses and radii comparable with observations found in the past are generated. Our model obeys different stability tests and energy conditions. The profiles for the potentials, matter variables, stability, and energy conditions are well behaved