Finch–Skea dark energy stars with vanishing complexity factor

Abstract

We make use of the complexity factor formalism for static and self-gravitating objects, recently proposed by L. Herrera (2018), for setting up a relativistic, anisotropic dark energy stellar model satisfying the vanishing complexity condition. The condition serves as an aid in closing the system of field equations for General Relativity. The popular Finch–Skea ansatz is used for the metric component, grr, with the temporal counterpart determined by imposing the vanishing complexity condition. We assess the physical acceptability of our dark energy stellar model according to the standard requirements for static, spherically symmetric compact matter, and we study the associated matter quantities with respect to the dark energy coupling parameter, α. The effect of α on our stellar model has been studied in detail. It is established that our model is regular and stable, and the radial pressure vanishes at the surface boundary as required by selecting a suitable range for α. We find that the coupling parameter influences the baryonic energy density and pressures; however, the pressure anisotropy remains largely unaffected. This is a novel feature of our dark-energy star model, obtained via the vanishing complexity condition. We further demonstrate the robustness of our model in predicting the observed radii of well-known compact objects such as 4U 1820-30, Vela X-1, LMC X-4, PSR J1614-2230, and PSR J1903+0327 by varying a free parameter arising in the Finck–Skea ansatz. Our findings show that our solution predicts masses beyond the standard general relativity limit of 2.0 M⊙ for neutron stars. The prediction of compact objects with masses in the range of 2.5 M⊙ within our solution-generating framework augers well for the observation of gravitational waves arising in binary mergers.