Presentation #201.09 in the session Exoplanets Orbital Dynamics.
γ Cep Ab is a typical S-type planet, which occupies a nearly perpendicular planetary orbit relative to the binary. Here we use the Markov Chain Monte Carlo (MCMC) sampler to conduct full N-body best-fitting to derive the orbital parameters of the planet. We further employ the non-restricted Eccentric Kozai–Lidov (EKL) mechanism to explain the extremely high mutual inclination of S-type planet γ Cep Ab. The EKL mechanism plays an essential role in exploring significant oscillations of the mutual inclination between the planet and the secondary. We perform qualitative analysis and extensive numerical integrations to investigate the flip conditions and timescales of γ Cep Ab’s orbit. When the planetary mass attains 15 MJ, the planet can reach imut ~ 113° with the critical initial conditions of imut < 60° and e1 < 0.7. The timescale for the first orbital flip decreases along with the increase of the perturbation Hamiltonian. The flipping orbits of γ Cep Ab are confirmed to have a large possibility to retain stable based on surfaces of section and the secular stability criterion. Furthermore, we extend EKL to general S-type planetary systems with a1/a2 ≤ 0.1, where the most intense excitation of i occurs when a1/a2 = 0.1 and e2 ~ 0.8, and the variation of planetary mass mainly affect the flip possibility where e1 ≤ 0.3.