NAI
2010 Annual Science Report
NASA Jet Propulsion Laboratory - Titan
Reporting | SEP 2009 – AUG 2010
Task 1.1.2 Models of the Internal Dynamics: Formation of Liquids in the Subsurface and Relationships With Cryovolcanism
Project Summary
The rate of the heat flow through the Titan ice crust sets a limit on how long water can exist in liquid form on the surface of Titan
Project Progress
Co-Investigator Christophe Sotin in collaboration with Postdoctoral Fellow Mathieu Choukroun and others have made progress on numerical simulations of heat transfer through Titan’s ice crust. Numerical simulations in 3D spherical coordinates and 3D Cartesian coordinates (thin shell) were conducted on a (256×256×256) grid. They were interested in the scaling of the vertical velocity for realistic values of the viscosity. One key parameter which controls the stability of the thermal boundary layer is the activation energy. But the larger the activation energy, the more challenging the numerical simulation. They ran 10 simulations with two different values of the viscosity at melting temperature (1013 and 1014 Pa.s) and 5 different values of the activation energy. The results are being processed. The velocities will allow addressing the question of how much time it takes for the particles embedded into the freezing ice at the base of the ice crust to reach the base of the conductive lid. A second aspect of the numerical simulations is to investigate the horizontal stress applied by the convection process at the base of the conductive lid and to compare it with the yield stress necessary to break the ice lid. They have calculated these values for each of the 10 numerical simulations and data are being processed.
Publications
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Béghin, C., Sotin, C., & Hamelin, M. (2010). Titan’s native ocean revealed beneath some 45km of ice by a Schumann-like resonance. Comptes Rendus Geoscience, 342(6), 425–433. doi:10.1016/j.crte.2010.03.003
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Choukroun, M., Grasset, O., Tobie, G., & Sotin, C. (2010). Stability of methane clathrate hydrates under pressure: Influence on outgassing processes of methane on Titan. Icarus, 205(2), 581–593. doi:10.1016/j.icarus.2009.08.011
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Davies, A. G., Sotin, C., Matson, D. L., Castillo-Rogez, J., Johnson, T. V., Choukroun, M., & Baines, K. H. (2010). Atmospheric control of the cooling rate of impact melts and cryolavas on Titan’s surface. Icarus, 208(2), 887–895. doi:10.1016/j.icarus.2010.02.025
- Lunine, J., Artemieva, N. & Tobie, G. (2010). Impact cratering on Titan: hydrocarbons versus water. Lunar and Planetary Science Conference.
- Lunine, J., Choukroun, M., Stevenson, D.J. & Tobie, G. (2009). Origin and Evolution of Titan. In: Brown, R.H., Lebreton, J.P. & Waite, H. (Eds.). Titan from Cassini-Huygens. New York: Springer.
- Sotin, C., Mitri, G., Rappaport, N., Schubert, G. & Stevenson, D. (2009). Titan’s Interior Structure. In: Brown, R.H., Lebreton, J.P. & Waite, H. (Eds.). Titan. Springer-Verlag.
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PROJECT INVESTIGATORS:
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PROJECT MEMBERS:
Mathieu Choukroun
Postdoc
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RELATED OBJECTIVES:
Objective 1.1
Formation and evolution of habitable planets.
Objective 2.2
Outer Solar System exploration
Objective 3.1
Sources of prebiotic materials and catalysts
Objective 3.2
Origins and evolution of functional biomolecules
Objective 3.3
Origins of energy transduction
