Impact of non-zero strange quark mass $(m_{s}\neq0)$ in $f(R,T)$ gravity admitting observational results of strange stars

Abstract

In this article we propose a new class of isotropic strange star using Buchdahl-I metric ansatz in the context of MIT bag model equation of state considering of non-zero strange quark mass $(m_{s})$ 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, {\it viz.}, $f(R,T)=R+2\alpha_{c}T$ where $\alpha_{c}$ is termed as the gravity-matter coupling constant, produces a tractable set of solutions of Einstein field equations. From the allowed numerical values of the coupling constant $(\alpha_{c})$, we have considered a range of $\alpha_{c}$ 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, for an arbitrary choice of bag constant $B=70~MeV/fm^{3}$, $m_{s}$ and $\alpha_{c}$ act as a constraining factor. Interestingly, the increment of $m_{s}$ and $\alpha_{c}$ results in a softer equation of state which leads to the decrease in the maximum mass and radius while negative values of $\alpha_{c}$ 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 study the effects of $m_{s}$ and $\alpha_{c}$ 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 obtained results agree well with the observed results. We note that the proposed model satisfies all the necessary energy conditions and stability criteria to emerge as a viable stellar configuration.