Exploring Hybrid Star Models With Quark and Hadronic Matter in f ( Q ) $f(Q)$ Gravity

Abstract

A static anisotropic hybrid star model is developed that includes strange quark matter and hadronic matter. The field equations are solved in the $f\left(Q\right)$ gravity framework (where $Q$ is the non-metricity) using the Finch–Skea metric. The relationship between density and pressure for strange quark matter is described using the MIT bag model equation, while for hadronic matter, the radial pressure and density are related by a linear equation of state. The compact star EXO 1785-248 is selected and five different values of the coupling constant are analyzed. To evaluate the physical feasibility of the model, a graphical analysis is performed for key properties, including the metric components, energy density, radial and tangential pressures, anisotropy, gradients, quark matter density and pressure, the equation of state parameter, energy conditions and the mass function. Stability and equilibrium of the star are further examined through parameters such as compactness, redshift, causality conditions, Herrera cracking, the adiabatic index and the Tolman–Oppenheimer–Volkoff equation. The results indicated that $f\left(Q\right)$ gravity effectively describes the macroscopic properties of hybrid stars.