Impact of non-zero strange quark mass (mₛ≠0) in $f(R,T)$ gravity admitting observational results of strange stars

In this article we propose a new class of isotropic strange star using Buchdahl-I metric ansatz and MIT bag model equation of state in presence of non-zero strange quark mass (mₛ) in the framework of modified $f(R,T)$ theory of gravity. The barotropic form of MIT bag model equation of state and a specific class of $f(R,T)$ model { viz.}, f(R,T)=R+2αcT where αc is termed as the gravity-matter coupling constant, produces a tractable set of solutions of Einstein field equations. From the numerical limit of the coupling constant (αc), we have considered a range of αc from -2.0 to 2.0. Maximum mass and radius in this model is found by numerically solving the TOV equations and we note that within the stability window imposed by energy per baryon calculation, for a particular bag constant B=70~MeV/fm³, mₛ and αc act as a constraining factor. Interestingly, the increment of mₛ and αc results in a softer equation of state which leads to the decrease in the maximum mass and radius while negative values of αc leads to a stiffer equation of state thereby increasing the maximum mass and radius in the present model. For physical application, we consider EXO 1745-248 and tabulate the effects of mₛ and αc on its radius. Using the formalism, we have analysed the characteristic properties of EXO 1745-248. Apart from that, we have predicted the radii of a wide range of strange star candidates in the context of $f(R,T)$ gravity and the results agree well with the observed properties. We note that our model satisfies all the necessary energy conditions and stability criteria to emerge as a viable stellar configuration.