Strong chaos induced by close encounters with Ceres and Vesta

Jacques Laskar (1) , Mickael Gastineau (1) , J.-B. Delisle (1) , Ariadna Farrés (1) , Agnès Fienga (1, 2, 3)

1 IMCCE - Institut de Mécanique Céleste et de Calcul des Ephémérides
2 LAOB - Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091)
3 UTINAM - Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213)

We consider the full Solar System including (1) Ceres and some of the main asteroids, (2) Pallas, (4) Vesta, (7) Iris, and (324) Bamberga. We show that close encounters among these small bodies induce strong chaotic behavior in their orbits and in those of many asteroids that are much more chaotic than previously thought. Even if space missions will allow very precise measurements of the positions of Ceres and Vesta, their motion will be unpredictable over 400 kyr. As a result, it will never be possible to recover the precise evolution of the Earth's eccentricity beyond 60 Myr. Ceres and Vesta thus appear to be the main limiting factors for any precise reconstruction of the Earth orbit, which is fundamental for the astronomical calibration of geological timescales. Moreover, collisions of Ceres and Vesta are possible, with a collision probability of 0.2% per Gyr.

Mots clés: chaos; methods: numerical; celestial mechanics; planets and satellites: dynamical evolution and stability; minor planets asteroids: individual: Ceres; minor planets asteroids: individual: Vesta

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]; Planétologie et astrophysique de la terre [astro-ph.EP]

Jacques Laskar, Mickael Gastineau, J.-B. Delisle, Ariadna Farrés, Agnès Fienga. Strong chaos induced by close encounters with Ceres and Vesta. Astronomy and Astrophysics - A&A, 2011, 532 (L4), 4 p. ⟨10.1051/0004-6361/201117504⟩. ⟨hal-00620783⟩