Celestial Mechanics News & Events

Abstract: We investigate the spin behavior of close-in rocky planets and the implications for their orbital evolution. The temporary captures in spin-orbit resonances are analyzed assuming that the planet rotation evolves under simultaneous actions of the torque due to the equatorial deformation and the tidal torque, both raised by the central star. We solve the spin-orbit (dissipative) problem through the simulation of the exact and averaged equations of motions. The results indicate that, whenever the planet rotation is trapped in a resonant motion, the orbital decay and the eccentricity damping are faster than the ones in which the rotation follows the so-called pseudo-synchronization. Applications are considered for the recently discovered hot super-Earths Kepler-10 b, GJ 3634 b and 55 Cnc e. The simulated dynamical history of these systems indicates the possibility of capture in several spin-orbit resonances; particularly, GJ 3634 b and 55 Cnc e can currently evolve under a non-synchronous resonant motion for suitable values of the parameters.

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