Structure and mass-radius stability of charged compact objects in symmetric teleparallel Euler–Heisenberg gravity

Abstract

In this work, we studied a relativistic model of a charged anisotropic compact star within the paradigm of modified symmetric teleparallel gravity coupled to nonlinear electrodynamics, namely f(Q)-Euler-Heisenberg gravity. The combined influence of non-metricity and quantum electrodynamic corrections introduces an effective stiffening of stellar matter, allowing the formation of compact objects with denser mass and compactness than those models suggested by general relativity. By adopting the MIT bag model equation of state, we obtain exact interior solutions elaborating an anisotropic fluid configuration interacting with a nonlinear electromagnetic field. The interior spacetime is smoothly matched to the corresponding exterior geometry derived within the same f(Q)-Euler-Heisenberg framework by means of the Darmois-Israel junction conditions. A detailed physical analysis of the results show that the energy density, radial and tangential pressures, anisotropy, and sound speeds remain regular throughout the stellar interior and satisfy all essential physical requirements. The equilibrium of the configuration is governed by a balance between gravitational, hydrostatic, electromagnetic, and anisotropic forces, as demonstrated by the generalized Tolman-Oppenheimer-Volkoff equation. The dynamical stability of the model is further ensured by the adiabatic index condition Γ > 4/3, indicating robustness against small radial perturbations. The resulting mass-radius relations, compactness, and surface redshift profiles exhibit smooth and physically acceptable behavior. When applied to observed compact object candidate PSR J1614-2230, the predicted mass and radius are consistent with current observational constraints. Instead of graphical analysis, we numerically calculated the predicted radius for five star candidates (PSRJ 1614-2230, PSR J074+6620, PSR J1959+2048, PSR J2215+5135, GW190814) which are again consistent with current observational constraints. These results demonstrate that the f(Q)-Euler-Heisenberg framework provides a physically viable extension of standard gravity capable of supporting heavier and more compact stellar configurations than those allowed within classical general relativity.