• DOI:10.1088/0004-637X/780/2/124
• Corpus ID: 118700510

Dynamical evolution and spin-orbit resonances of potentially habitable exoplanets. The case of GJ 667C

@inproceedings{Makarov2013DynamicalEA,
  title={Dynamical evolution and spin-orbit resonances of potentially habitable exoplanets. The case of GJ 667C},
  author={Valeri V. Makarov and Ciprian T. Berghea},
  year={2013}
}

• V. Makarov, C. Berghea
• Published 19 November 2013
• Physics

We investigate the dynamical evolution of the potentially habitable superearth GJ 667Cc in the multiple system of at least two exoplanets orbiting a nearby M dwarf, paying special attention to its spin-orbital state. The published radial velocities for this star are re-analyzed and evidence is found for additional periodic signals, which could be taken for two additional planets on eccentric orbits. Such systems are not dynamically viable and break up quickly in numerical integrations. The nature of the bogus signals in the available data remains unknown. Limiting the scope to the two originally detected planets, we assess the dynamical stability of the system and find no evidence for bounded chaos in the orbital motion, unlike the previously investigated planetary system of GJ 581. The orbital eccentricity of the planets b and c is found to change cyclicly in the range 0.06 0.28 and 0.05 0.25, respectively, with a period of approximately 0.46 yr, and a semimajor axis that little varies. Taking the eccentricity variation into account, numerical integrations are performed of the differential equations modeling the spin-orbit interaction of the planet GJ 667Cc with its host star, including fast oscillating components of both the triaxial and tidal torques and assuming a terrestrial composition of its mantle. Depending on the interior temperature of the planet, it is likely to be entrapped in the 3:2 (probability 0.51) or even higher spin-orbit resonance. It is less likely to reach the 1:1 resonance (probability 0.24). Similar capture probabilities are obtained for the inner planet GJ 667Cb. The estimated characteristic spin-down times are quite short for the two planets, i.e., within 1 Myr for planet c and even shorter for planet b. Both planet arrived at their current and, most likely, ultimate spin-orbit states a long time ago. The planets of GJ 667C are most similar to Mercury of all the Solar System bodies, as far as their tidal properties are concerned. However, unlike Mercury, the rate of tidal dissipation of energy is formidably high in the planets