Dependence of maximum mass of strange star on finite strange quark mass (m s ≠ 0)

Abstract

Abstract In this article we analyze a class of compact object in spheroidal geometry described by Vaidya–Tikekar model and MIT bag model equation of state considering the finite mass of strange quark (m s). The maximum mass and radius is found by maximizing the square of radial sound velocity ( v r 2 ) at the centre. For monotonically decreasing nature of the sound velocity we note that an upper limit of the spheroidal parameter (λ) exists. Therefore for the calculation of maximum mass arbitrary choice of λ is not possible. The effect of strange quark mass on the maximum mass is found to satisfy previously obtained result (Li et al 2021 Eur. Phys. J. C 81 921). To apply the present model we consider the compact stars 4U 1608-52 and 4U 1820-30. The stability of strange quark matter inside these compact objects is explored by taking different values of the bag constant B. It is found that 4U 1608-52 may be categorized as strange star with wider stability window for three-flavor quark matter whereas 4U 1820-30 only shows metastability. The model is found to be stable against small radial perturbation. One possible drawback of the present model is the prediction of maximum mass from mass-radius plot. For this reason we have predicted the maximum mass from alternative approach.