Moment of inertia and compactness of quark stars within the context of f(R, T, L m) gravity

Within the metric formalism of f(R, T, L-m) gravity theories, we investigate the hydrostatic equilibrium structure of compact stars taking into account both isotropic and anisotropic pressure. For this purpose, we focus on the f(R, T, L-m) = R + alpha TLm model, where alpha is a free parameter. We derive the modified TOV equations and the relativistic moment of inertia in the slowly rotating approximation. Using an equation of state (EoS) for color-superconducting quark stars, we examine the effects of the alpha TLm term on the different macroscopic properties of these stars. Our results reveal that the decrease of the parameter alpha leads to a noticeable increase in the maximum-mass values. For negative alpha with sufficiently small divided by alpha divided by, we obtain a qualitative behavior similar to the general relativistic (GR) context, namely, it is possible to obtain a critical stellar configuration such that the mass reaches its maximum. However, for sufficiently large values of divided by alpha divided by keeping negative alpha, the critical point cannot be found on the mass-radius diagram. We also find that the inclusion of anisotropic pressure can provide masses and radii quite consistent with the current observational measurements, which opens an outstanding window onto the physics of anisotropic quark stars. By comparing the I - C relations of isotropic quark stars in modified gravity, we show that such a correlation remains almost unchanged as the parameter alpha varies from GR counterpart. On the other hand, given a fixed alpha, the I - C relation is insensitive to variations of the anisotropy parameter beta to O(4%).