Event type
Event date
Venue
GAP room
Speaker
Nelson Callegari (UNESP - DEMAC)
Abstract:Callegari & Rodríguez (2013) numerically show that, in the domain of the classical model of spin-orbit resonances developed for natural satellites and Mercury, (Goldreich & Peale 1966), the rotation of super-earths with orbital period P<1 day may be strongly disturbed by the stelar torque. The evolution through resonance, induced by tidal forces, of the motion of rotation of many planets has been explored in Rodríguez et al. (2012). For those planets which admit eccentric orbit, the current rotational configuration (i.e., considering the current orbital elements) may not be synchronous and other spin-orbit configurations are possible.
Terrestrial exoplanets can have inner differentiated structure (e.g. Valencia et al. 2006, Gong & Zhou 2012). Thus, in view of many efforts on the modelling the coupled mantle-core rotation of Mercury and the Earth (e.g. Peale et al. 2014, Szeto e Xu 1997), Callegari & Batista Ribeiro (2014) (hereafter denoted by CB2014), numerically study the generalized spin-orbit model with ravitational coupling for super-earths. The model has been applied to planet Kepler-10b, admitting a terrestrial-like structure according to Gong & Zhou (2012).
CB2014 show that the motion of an outer layer (mantle+crust) suffers small perturbation of the core through core-mantle gravitational coupling. In particular, this result is valid for the case of a solid inner core with a small mass: a factor of about 1/4 of the mantle's mass in the case of Kepler-10b (CB2014). In a scenario of evolution into an equilibrium state of rotation, the coupling would be neglected since the topology of the phase space (regimes of motion in resonance, separatrices etc) is not signifinatly affected. However, CB2014 show evidences that the motion of rotation of the solid inner core of a
super-earth like Kepler-10b can be strongly disturbed by the torque of the outer layers. For instance, in the perturbed case, the separatriz of the synchronous rotation of the inner core occupy large areas of the phase space, even in the case of quasi-circular orbits e~0.
In this work, we show new results on the rotation of Kepler-10b where we adopt different models of inner structure (Gong & Zhou 2012), wide regions of initial conditions and parameters. A briefly discussion is given on the geophysical consequences (e.g. mechanisms of generation of planetary magnetic fields), for a planet whose inner core has a motion strongly disturbed by outer layers of the planet. We will show results obtained with the same methodology developed in CB2014 for other super-earths like Kepler-78b and KOI-55b,c.
In this work, we show new results on the rotation of Kepler-10b where we adopt different models of inner structure (Gong & Zhou 2012), wide regions of initial conditions and parameters. A briefly discussion is given on the geophysical consequences (e.g. mechanisms of generation of planetary magnetic fields), for a planet whose inner core has a motion strongly disturbed by outer layers of the planet. We will show results obtained with the same methodology developed in CB2014 for other super-earths like Kepler-78b and KOI-55b,c.