We numerically investigate the dynamics of rotation of several close-in
terrestrial exoplanet candidates. In our model, the rotation of the planet is
disturbed by the torque of the central star due to the asymmetric equilibrium
figure of the planet. We model the shape of the planet by a Jeans spheroid. We
use surfaces of section and spectral analysis to explore numerically the
rotation phase space of the systems adopting different sets of parameters and
initial conditions close to the main spin-orbit resonant states. One of the
parameters, the orbital eccentricity, is critically discussed here within the
domain of validity of orbital circularization timescales given by tidal models.
We show that, depending on some parameters of the system like the radius and
mass of the planet, eccentricity etc, the rotation can be strongly perturbed
and a chaotic layer around the synchronous state may occupy a significant
region of the phase space. 55 Cnc e is an example.Comment: In Press. Celestial Mechanics and Dynamical Astronomy. 30 pages, 9
figure