On the improved orbit stability criterion around an irregularly shaped body

The trajectory stability around the small object has intrigued the researchers concern recently, since its irregular potential field may make the orbit unstable. As an important result obtained so far, the instability occurs when the orbit is direct and the orbital period is identical to that of the body spin period. This trivial instability as well as the other two representative resonance frequencies were studied and the criterion evaluating the associated unstable band in terms of the body spin rate was developed by the authors ⁴⁾. This paper gives the new stability criteria including the secular perturbation effect. Numerical illustration first deals with the orbit around a small Tri-axial ellipsoid and secondly the Saturn's ring and division structure interpretation attempt through the properties developed here. The latter is given as just a hypothesis. However, the former numerical illustration supports the analysis well accounting for the characteristics.