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[29.01] Coupling Between Terrestrial and Giant Planets During Migration

C. Agnor (UC Santa Cruz)

The timescales for the formation of Uranus and Neptune (10⁶-10⁹ yr) and the subsequent migration of all the outer planets (a few \times 10⁷- 10⁸ yr) overlap with the the formation timescale of the terrestrial planets (20-200 Myr based on isotopic data and accretion simulations). It has also been suggested that the late formation and/or migration of the giant planets may have triggered the Late Heavy Bombardment of the Moon ~700 Myr after the terrestrial planets formed (e.g. Levison et al. 2001, Gomes et al. 2005).

How would the gross changes in the dynamical structure of the migrating giant planets affect the inner terrestrial planets? Changes in the orbital elements of the outer planets alter the amplitudes and characteristic frequencies of their perturbations on the rest of the planetary system. Thus, the migration of the giant planets after terrestrial planet formation could result in strong external forcing of the inner solar system.

The emphasis of this study is two-fold: 1) to use the dynamical state of the terrestrial planets to constrain the timing and/or conditions of giant planet migration, and 2) to explore the specific effects of giant planet migration on the inner solar system.

I have performed numerical N-body integrations that address how the late migration of the giant planets alters the dynamical state of the inner solar system. These integrations include the four migrating giant planets, the fully formed terrestrial planets and are performed using the Symba integrator (Duncan et al. 1998). The initial results indicate that the migration of Jupiter, Saturn, Uranus and Neptune can result in strong dynamical coupling with the terrestrial planets. The gross effects of this coupling include destabilization of the terrestrial system, additional planetary collisions, and the excitation of Mercury and Mars to more eccentric orbits.

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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.