Implication of f(Q,T) gravity on the formation of the charge compact stars and constraining their mass-radius relations in lower mass gap region

Abstract

In this paper, we explore a charged isotropic stellar model within the framework of $f(Q,T)$ gravity. By deriving solutions to the modified field equations, we systematically analyze the physical characteristics of the stellar configuration to assess its relevance and stability. Our results show that the electric charge distribution adheres to key criteria of regularity and finiteness. Notably, the charge behavior is significantly affected by the charge parameter σ and the coupling parameter m, while demonstrating stability in response to variations in n. We find that the surface charge ranges from $1.85\times {10}^{20}$ C to $3.31\times {10}^{20}$ C, which is consistent with prior research, highlighting the crucial role of electric charge in maintaining stellar stability against gravitational collapse. Additionally, our analysis of density and isotropic pressure reveals both quantities to be finite and regular at the core, effectively eliminating the presence of singularities. The central density aligns well with typical neutron star configurations, while the isotropic pressure approaches zero at the boundary. Investigating the causality conditions, we confirm that the sound speed remains subluminal, and the adiabatic index $\Gamma \left(r\right)$ exceeds the critical threshold of $\frac{4}{3}$, indicating stability throughout the stellar configuration. The equilibrium of forces, evaluated through modified TOV equations, illustrates a harmonious balance among gravitational, electrostatic, and hydrostatic forces. The relationship between mass and radius indicates a maximum mass ranging from $1.83M_{\odot }$ to $2.99M_{\odot }$, with radii that are consistent with observational data. In conclusion, our findings underscore the substantial impact of the charge parameter σ in enhancing the compactness and stability of higher-mass compact stars, providing support for the existence of stars within the mass gap region.