| Abstract : | This work establishes a dynamical mechanism to explore the orbital and escape dynamics of stars in giant disc galaxies that have double-barred structures. In the study, a double-barred galaxy model composed of a spherical bulge, a primary bar, a secondary bar, a flat disc, and a NFW dark halo component is studied. We integrate the initial conditions of stellar orbits in several phase planes to obtain a complete view of the bounded and escaping stellar motion in the phase space. Moreover, invariant manifolds associated with the Lyapunov orbits around the unstable equilibrium points at the ends of both bars have been analysed. Our result states that the presence of a secondary bar is related to an inflow mechanism that helps to escalate energy generation at the centre. In the process, this helps to guide the unstable manifolds near the primary bar ends to form spiral arms. This supports the formation of spiral arms due to a bar-driven escape mechanism in active and nuclear starburst galaxies. |
