Find in Library

Abstract The null and timelike geodesic motion in the vicinity of the Schwarzschild black hole in the presence of the string cloud parameter a and the quintessence field parameter q is studied. The ranges for both the parameters a and q are determined, which allow the existence of the black hole. In the radial motion of photon, the coordinate time t first decreases with the increasing values of both the parameters a and q and then in the close proximity of the horizon of the black hole, there is a turning point, after which the effect of the quintessence field is just opposite on the time t. For the massive particles, the proper time $$\tau $$ τ decreases with increasing values of the parameter a and increases with increase in the value of the parameter q. In the same case of the massive particles, the coordinate time t decreases with increase in the values of both the parameters a and q. Further, it is found that for test particles, the stable circular orbits exist in this spacetime for small values of both the parameters i.e., for $$0<a\ll 1$$ 0 < a ≪ 1 and $$0<q\ll 1$$ 0 < q ≪ 1 . It is observed that the radii of the null circular orbits increase as the values of the parameters a and q increase. While in the case of the timelike geodesics, the radii of the circular orbits increase as the value of the parameter a increases, and they decrease as the value of the parameter q increases.