Tidal Deformation of an Icy Moon with a Subsurface Ocean
| Thesis title in Czech: | Slapová deformace ledového měsíce s podpovrchovým oceánem |
|---|---|
| Thesis title in English: | Tidal Deformation of an Icy Moon with a Subsurface Ocean |
| Key words: | Ledové měsíce|slapy|elastická deformace|Navier-Stokesova rovnice|přiblížení mělké vody |
| English key words: | Icy moons|tides|elastic deformation|Navier-Stokes equation|shallow water approximation |
| Academic year of topic announcement: | 2018/2019 |
| Thesis type: | diploma thesis |
| Thesis language: | angličtina |
| Department: | Department of Geophysics (32-KG) |
| Supervisor: | prof. RNDr. Ondřej Čadek, CSc. |
| Author: | hidden - assigned and confirmed by the Study Dept. |
| Date of registration: | 05.01.2019 |
| Date of assignment: | 11.01.2019 |
| Confirmed by Study dept. on: | 25.04.2019 |
| Date and time of defence: | 11.02.2021 08:30 |
| Date of electronic submission: | 06.01.2021 |
| Date of submission of printed version: | 06.01.2021 |
| Date of proceeded defence: | 11.02.2021 |
| Opponents: | RNDr. Ondřej Šrámek, Ph.D. |
| Advisors: | doc. RNDr. Ondřej Souček, Ph.D. |
| Guidelines |
| Enceladus is one of the few Solar System bodies for which there is direct evidence of subsurface oceans. Observations by Cassini suggest that Enceladus' ocean contains nutrients, organic molecules and energy sources, which are believed to be essential for the emergence of life. Although our knowledge of Enceladus has increased dramatically over the past fifteen years, the heat sources maintaining the ocean in a liquid state are still unclear. The goal of the diploma project is to answer the question of whether the tides in the subsurface ocean can produce enough heat to keep the ocean liquid over a geological time scale. In the first step, the student will solve two independent problems: (i) Elastic deformation of a spherical ice shell induced by a tidal force, and (ii) viscous flow in the ocean driven by the same force using a shallow water approximation. Both problems will be solved using a spectral decomposition of the appropriate partial differential equations. In the next step, the two problems will be coupled through a boundary condition at the ice-water interface and solved simultaneously. The resulting ocean flow will be used to estimate the mechanical energy dissipated in the liquid part of the moon and discussed in the context of Enceladus' global heat budget. Possible extensions of the work: (i) using a more general rheology of ice (Maxwell, Andrade etc.), (ii) including the tidal deformation of Enceladus' core, (iii) considering irregular shape of the ice shell, (iv) replacing shallow water equations by 3d equations, and (v) application to other icy moons with subsurface oceans (Europa, Mimas etc.). |
| References |
| Basic information about icy moons with subsurface oceans:
Nimmo, F., Pappalardo, R. T., 2016. Ocean worlds in the outer solar system. J. Geophys. Res.-Planets 121, 1378-1399. Elastic deformation of a spherical shell: Souček et al., 2016. Effect of the tiger stripes on the deformation of Saturn's moon Enceladus. Geophys. Res. Lett. 43, 7417-7423. Souček et al., 2018. Tidal dissipation in Enceladus' uneven, fractured ice shell, manuscript. Shallow water approximation: Einspigel D., 2012. Barotropic ocean tide model, diploma thesis, Charles University, Prague. Spectral method: Matas, J., 1995. Mantle viscosity and density structure, diploma thesis, Charles University, Prague. Recent papers on the same topic: Matsuyama et al., 2018. Ocean tidal heating in icy satellites with solid shells. Icarus 312, 208-230. Enceladus' heat budget: Nimmo et al., 2018. The thermal and orbital evolution of Enceladus: observational constraints and models. In: Schenk, P. M. et al. (Ed.), Enceladus and the Icy Moons of Saturn. Univ. of Arizona, Tucson, p. in press. Souček et al., 2018. Tidal dissipation in Enceladus' uneven, fractured ice shell, manuscript. |