Secular Spin-Orbit Dynamics in Exoplanetary Systems: Gauss Rings with Spins and Tides

Abstract

Ever since the discovery of the first exoplanet by Mayor & Queloz in the 1995, observers have detected thousands of planets outside the solar system. Hundreds of these planets have Jovian masses and orbit their host stars in highly eccentric orbits with periods of only a few days, the so-called “Hot Jupiters”. Another cases are observed with planets residing in wide eccentric binaries, where the binary companion can strongly perturb the planet’s orbit leading to interesting dynamical evolution. In these configurations, tidal effects are expected to cause significant long-term spin-orbit evolution driving the planetary systems into some equilibrium configuration. In this thesis, we develop and test a numerical tool which enables us to investigate the complex dynamical behaviors expected in exo-planetary systems. The work involves extending Gauss’s algorithm for orbital averaging to allow for slow spin dynamics, together with spin-orbit evolution induced by dissipative tides. The numerical tool is then used to revisit some of the studies done on the spin-orbit dynamics of our Earth-Moon system including Goldreich (1966) , Mignard(1981) and Ward(1975). It is then used to investigate the tidal-Kozai Migration of the HD 80606 exo-planetary system. Our developed non perturbative approach will allow us to consider phase space regimes that are not accessible using the usual perturbative approximations and hence it might prove to be fundamental in obtaining a more complete picture for the spin-orbit studies to be done on exoplanets.