Particle Dynamics within the Habitable Zone of Extra Solar Planets

The orbital stability properties of terrestrial planets within the habitable zone of the star HD4208 (Vogt et al. 2001) is investigated. The habitable zone is determined from Kasting et al. (1993) and provides constrains on Kepler parameters within the (a,e)-space. Independent numerical simulations, using symplectic and interpolation methods (Chambers et al. 2001), are used to study dynamical characteristics (chaotic and confinement within the system's orbital parameter phase space. The MEGNO indicator (Gozdziewski et al. 2001) is used to measure the chaotic nature of the time evolution of Keplerian orbital parameters. Stability properties are inferred by directly considering the dynamics of 2 x 10^3 test particles distributed throughout the habitable zone. The presence of several mean motion resonances are capable in eccentricity excitation up to e = 0.8 for the test particles within the habitable zone. This kind of theoretical dynamical analysis will help future space-based search missions for habitable planets, by providing a mission targeting list of observed extrasolar systems with a high confidence in harbouring terrestrial like planets on dynamically stable orbits confined within the habitable zone.