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Christophe Sotin Colloquium Abstract (Oct 5, 2016)

Titan: an Organic World of Two Oceans

The Cassini mission has demonstrated that Titan is an organic world of two oceans: the large hydrocarbon seas at Titan’s North Pole and the global deep salty water ocean predicted to be squeezed between an icy crust and a layer of high-pressure ice. The talk first summarizes the observations that lead to our present understanding of Titan’s organic cycle and its interior structure and composition. Titan has many of the necessary conditions to fulfill the requirements of a habitable world.  It is the only place in the solar system where formation of organics can be witnessed in addition of being the only place besides Earth with stable liquid at its surface and the only satellite with a dense atmosphere. The presentation will also describe places on Titan where water and organic material may have been in contact during long periods of time.

 

Technical Talk:

Two-phase convection in the high pressure ice layer of the large icy moons

Observations by the Galileo and Cassini missions strongly suggest the presence of a deep global ocean inside the large icy moons Ganymede and Titan. Interior models based on (i) the interpretation of gravity coefficient (mass distribution with depth) and (ii) phase diagram of water ice, propose that the ocean is squeezed between the icy crust and a high-pressure ice layer that prevent direct contact between the ocean and the rocky core. This study describes results of 2D numerical simulations of two-phase convection in the high-pressure ice layer. It shows the role of partial melt forming at both interfaces with convection providing the process by which chemical compounds can be transferred from the deep interior to the surface.

Technical talk abstract (PDF)