Features of motion around global monopole in asymptotically dS/AdS spacetime

In this paper, we study the motion of a test particle and light around the global monopole in asymptotically dS/AdS spacetime. The motion of a test particle and light in the exterior region of the global monopole in dS/AdS spacetime has been investigated. Although the motion of the test particle is quite different from the case in asymptotically flat spacetime, the behaviour of light (null geodesic) remains unchanged except for an energy (frequency) shift. Through a phase-plane analysis, we prove analytically that the existence of a periodic solution to the equation of motion for a test particle will not be altered by the presence of the cosmological constant and the deficit angle, whose presence only affects the position and type of critical point on the phase plane. We also show that the apparent capture section of the global monopole in dS/AdS spacetime is quite different from that in flat spacetime.