Today (15.05.08) we have 288 exoplanets, 25 multisystems (Schneider, 2008). Most of the discovered extrasolar planets are massive, Jupiter-sized bodies, moving around their host stars along considerably eccentric orbits. Low-mass planets like the Earth cannot still be observed in these systems. There are many mean-motion resonances in the known extrasolar planetary systems.
We investigate the low-mass exoplanet possible motions within the framework of the restricted elliptical three-body problem using numerical and analytical tools. Especially interesting is the possibility of near-circular motions in the habitability zones – regions near the star, where the physical conditions
are favourable for liquid water existence. Near-circular orbits in the habitability zones are favour for highly evolved matter.