DPS 2001 meeting, November 2001
Session 23. Solar System Origins I
Oral, Chairs: G. Stewart, J. Chambers, Wednesday, November 28, 2001, 3:00-4:30pm, Regency GH

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[23.06] Mixing the Cores and Envelopes of Giant Planets: Consequences for Formation Models

T Guillot (OCA/Cassini (CNRS))

Atmospheric measurements and interior models show that Jupiter, Saturn, Uranus and Neptune contain significant amounts of heavy elements, well above the solar abundances. Part of these heavy elements appear to be embedded in the planets' cores, the rest being distributed in their hydrogen-helium envelopes. Detailed dynamical simulations show that most of these heavy elements appear to have been delivered when the protoplanets were not very massive, implying that upward mixing had to occur anyway.

We will present two mecanisms that can provide the required mixing by overcoming the strongly stabilizing compositional gradient near the core/envelope interface. One is adiabatic compression, shown to lead to a favorable increase in temperature in water compared to hydrogen. A second and perhaps more promising one is a Rayleigh-Taylor (shear) instability created by the different angular momenta in the core and in the envelope. Given that giant impacts might be able to deliver heavy elements to the planets' centers, the cores of the giant planets may not be primordial after all...

If you would like more information about this abstract, please follow the link to http://www.obs-nice.fr/guillot. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: guillot@obs-nice.fr

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