Structure of Quark Stars in <i>f</i>(<i>R</i>) Gravity

ABSTRACT We explore gravity, a classical extension of general relativity, and evaluate its applicability to compact stars. As a modification of Einstein's theory, gravity serves as a useful framework for investigating gravitational effects in ultra‐relativistic regimes where (standard) general relativity may break down, while remaining consistent with it in weak‐field limits. In this work, we derive a second‐order modified Tolman–Oppenheimer–Volkoff (MTOV) system, consisting of four coupled second‐order differential equations, for general gravity. This formulation is applied to static, spherically symmetric strange quark stars modeled using the MIT Bag equation of state. We propose two models, each incorporating a single parameter that governs the deviation from general relativity. The MTOV equations are solved numerically using the Runge–Kutta‐Fehlberg method, and the results are compared to those obtained in general relativity. Our findings demonstrate that gravity can yield distinct and physically meaningful modifications to the properties of compact stars. We further examine the contributions of second‐ and higher‐order corrections in the scalar‐tensor sector of the gravitational action.