Abstract

The equation of state for the Chaplygin gas has been proposed as a dynamical dark-energy candidate, offering a unified scenario for describing dark matter and dark energy within the field of cosmology. Now, the fluid-based model has been utilized to investigate the structure of compact stars, proposed as an alternative explanation for the mass gap between neutron stars and black holes in the realm of quantum gravity. This intriguing feature offers a new perspective for studying compact astrophysical objects within the strong-field regime. In the present study, we investigate the structural properties of anisotropic dark energy stars in R² gravity, particularly focusing on the impact of gravity's free parameter a and the parameter β, which controls the degree of anisotropy on stellar structure. We numerically solve the hydrostatic equilibrium equations in R² gravity, thus deriving the mass-radius relationships and compactness of the stars. It is demonstrated that the inclusion of the fluid anisotropy has notable influences on stellar mass, thereby influencing other global properties under investigation. Furthermore, using standard methods, we check the stability of the configuration by evaluating the static stability criterion, the adiabatic index, the speed of sound and verifying the energy conditions. Finally, our analysis involves astronomical constraints on pulsar masses and radii, based on recent NICER data along with the gravitational wave event GW170817.