Exploring physical features of anisotropic strange stars beyond standard maximum mass limit in $f\left(R,\mathcal {T}\right)$ gravity

Abstract

We study a specific model of anisotropic strange stars in the modified\n$f\\left(R,\\mathcal{T}\\right)$-type gravity by deriving solutions to the\nmodified Einstein field equations representing a spherically symmetric\nanisotropic stellar object. We take a standard assumption that\n$f(R,\\mathcal{T})=R+2\\chi\\mathcal{T}$, where $R$ is Ricci scalar, $\\mathcal{T}$\nis the trace of the energy-momentum tensor of matter, and $\\chi$ is a coupling\nconstant. To obtain our solution to the modified Einstein equations, we\nsuccessfully apply the `embedding class 1' techniques. We also consider the\ncase when the strange quark matter (SQM) distribution is governed by the\nsimplified MIT bag model equation of state given by\n$p_r=\\frac{1}{3}\\left(\\rho-4B\\right)$, where $B$ is bag constant. We calculate\nthe radius of the strange star candidates by directly solving the modified TOV\nequation with the observed values of the mass and some parametric values of $B$\nand $\\chi$. The physical acceptability of our solutions is verified by\nperforming several physical tests. Interestingly, besides the SQM, another type\nof matter distribution originates due to the effect of coupling between the\nmatter and curvature terms in the $f\\left(R,\\mathcal{T}\\right)$ gravity theory.\nOur study shows that with decreasing the value of $\\chi$, the stellar systems\nunder investigations become gradually massive and larger in size, turning them\ninto less dense compact objects. It also reveals that for $\\chi<0$ the\n$f\\left(R,\\mathcal{T}\\right)$ gravity emerges as a suitable theory for\nexplaining the observed massive stellar objects like massive pulsars,\nsuper-Chandrasekhar stars and magnetars, etc., which remain obscure in the\nstandard framework of General Relativity (GR).\n