Quark stars with 2.6 $$M_\odot $$ M ⊙ in a non-minimal geometry-matter coupling theory of gravity

Abstract

Abstract This work analyses the hydrostatic equilibrium configurations of strange stars in a non-minimal geometry-matter coupling (GMC) theory of gravity. Those stars are made of strange quark matter, whose distribution is governed by the MIT equation of state. The non-minimal GMC theory is described by the following gravitational action: $$f(R,L)=R/2+L+\sigma RL$$ f ( R , L ) = R / 2 + L + σ R L , where R represents the curvature scalar, L is the matter Lagrangian density, and $$\sigma $$ σ is the coupling parameter. When considering this theory, the strange stars become larger and more massive. In particular, when $$\sigma =50$$ σ = 50 km $$^2$$ 2 , the theory can achieve the 2.6 $$M_\odot $$ M ⊙ , which is suitable for describing the pulsars PSR J2215+5135 and PSR J1614-2230, and the mass of the secondary object in the GW190814 event. The 2.6 $$M_\odot $$ M ⊙ is a value hardly achievable in General Relativity, even considering fast rotation effects, and is also compatible with the mass of PSR J0952-0607 ( $$M = 2.35 \pm 0.17 ~M_\odot $$ M = 2.35 ± 0.17 M ⊙ ), the heaviest and fastest pulsar in the disk of the Milky Way, recently measured, supporting the possible existence of strange quark matter in its composition. The non-minimal GMC theory can also give feasible results to describe the macroscopical features of strange star candidates.