Quark stars in massive gravity might be candidates for the mass gap objects

Abstract

AbstractWe have investigated the structural properties of strange quark stars (SQSs) in a modified theory of gravity known as massive gravity. In order to obtain the equation of state (EOS) of strange quark matter, we have employed a modified version of the Nambu–Jona-Lasinio model (MNJL) which includes a combination of NJL Lagrangian and its Fierz transformation by using weighting factors $$(1-\alpha )$$ ( 1 - α ) and $$\alpha .$$ α . Additionally, we have also calculated dimensionless tidal deformability $$(\Lambda )$$ ( Λ ) in massive gravity. To constrain the allowed values of the parameters appearing in massive gravity, we have imposed the condition $$\Lambda _{1.4 {M}_{\odot }}\lesssim 580 .$$ Λ 1.4 M ⊙ ≲ 580 . Notably, in the MNJL model, the value of $$\alpha $$ α varies between zero and one. As $$\alpha $$ α increases, the EOS becomes stiffer, and the value of $$\Lambda $$ Λ increases accordingly. We have demonstrated that by softening the EOS with increasing the bag constant, one can obtain objects in massive gravity that not only satisfy the constraint $$\Lambda _{1.4 {M} _{\odot }}\lesssim 580,$$ Λ 1.4 M ⊙ ≲ 580 , but they also fall within the unknown mass gap region $$(2.5{M}_{\odot }-5{M}_{\odot }).$$ ( 2.5 M ⊙ - 5 M ⊙ ) . To establish that the obtained objects in this region are not black holes, we have calculated Schwarzschild radius, compactness, and $$\Lambda _{{M_{TOV}}}$$ Λ M TOV in massive gravity.