Ground-based observations of Phoebe (S9) and its rotational dynamics

Analysis of CCD observations of Phoebe, the 9th satellite of Saturn (visual magnitude of about 16.5), with a mirror astrograph ZA-320M at Pulkovo Observatory in Saint-Petersburg are presented. Photometric observations are performed both in the integral band of the telescope and in bands BVR of the Johnson system. Reference catalogues USNO-A2.0 (for R - filter and integral observations) and Ticho-2 (for V and B - filters) were used. Rotational light-curve data for Phoebe taken over a short time span (2-8 hours) for several nights are presented. Numerical investigation of the evolution of Phoebeʹs rotational dynamics is carried out. The probability of Phoebeʹs capture in resonant states that are distinct from 1:1 is estimated.