Symplectic integration of hierarchical stellar systems

Symplectic integration has been used successfully for many years now for the study of dynamics in planetary systems. This technique takes advantage of the fact that in a planetary system, the mass of the central body is much larger than all the other ones; it fails if all massive bodies have comparable masses, such as in multiple stellar systems. A new symplectic integrator is presented that permits the study of the dynamics of hierarchical stellar systems of any size and shape, provided that the hierarchical structure of the system is preserved along the integration. Various application tests of this new integrator are given, such as the gap formation in circumbinary disks, the Kozai resonance in triple systems, the truncated circumbinary disk in the quadruple system GG Tauri, and the dynamics of the sextuple system Castor.