Impact of the frequency dependence of tidal Q on the evolution of planetary systems

P. Auclair-Desrotour (1, 2, 3) , C. Le Poncin-Lafitte (3) , S. Mathis (4, 1)

1 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
2 IMCCE - Institut de Mécanique Céleste et de Calcul des Ephémérides
3 SYRTE - Systèmes de Référence Temps Espace
4 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique

Context. Tidal dissipation in planets and in stars is one of the key physical mechanisms that drive the evolution of planetary systems.Aims. Tidal dissipation properties are intrinsically linked to the internal structure and the rheology of the studied celestial bodies. The resulting dependence of the dissipation upon the tidal frequency is strongly different in the cases of solids and fluids.Methods. We computed the tidal evolution of a two-body coplanar system, using the tidal-quality factor frequency-dependencies appropriate to rocks and to convective fluids.Results. The ensuing orbital dynamics is smooth or strongly erratic, depending on the way the tidal dissipation depends upon frequency.Conclusions. We demonstrate the strong impact of the internal structure and of the rheology of the central body on the orbital evolution of the tidal perturber. A smooth frequency-dependence of the tidal dissipation causes a smooth orbital evolution, while a peaked dissipation can produce erratic orbital behaviour.

Keywords: celestial mechanics; planet-star interactions; planets and satellites: dynamical evolution and stability; hydrodynamics

Domains: Astrophysics [astro-ph]

P. Auclair-Desrotour, C. Le Poncin-Lafitte, S. Mathis. Impact of the frequency dependence of tidal Q on the evolution of planetary systems. Astronomy and Astrophysics - A&A, 2014, 561, pp.L7. ⟨10.1051/0004-6361/201322782⟩. ⟨cea-01162328⟩