#Enceladus tiger stripes tidal heating series

Gravitational spreading, bookshelf faulting, and tectonic evolution of the south polar terrain of Saturn’s moon Enceladus. Constraining the heat flux between Enceladus’ tiger stripes: numerical modeling of funiscular plains formation. A fracture history on Enceladus provides evidence for a global ocean. in Enceladus and the Icy Moons of Saturn (eds Schenk, P. Enceladus’s measured physical libration requires a global subsurface ocean. The gravity field and interior structure of Enceladus. A salt-water reservoir as the source of a compositionally stratified plume on Enceladus. Postberg, F., Schmidt, J., Hillier, J., Kempf, S. Enceladus’s ice shell structure as a window on internal heat production. Fracture penetration in planetary ice shells. Pressurized oceans and the eruption of liquid water on Europa and Enceladus. Sustained eruptions on Enceladus explained by turbulent dissipation in tiger stripes. How the geysers, tidal stresses, and thermal emission across the south polar terrain of Enceladus are related. Cassini observes the active south pole of Enceladus. The sequence of fissures then cascades outwards until the loading becomes too weak or the background shell thickness becomes too great to permit through-going fractures. The steadily erupting water ice loads the flanks of the open fissure, causing bending in the surrounding elastic plate and further tensile failure in bands parallel to the first fracture-a process that may be unique to Enceladus, where the gravity is too weak for compressive stresses to prevent fracture propagation through the thin ice shell.

The tensile stresses are thereby relieved, preventing a similar failure at the opposite pole. Here we propose that secular cooling, which leads to a thickening of the ice shell and building of global tensile stresses 5, 6, causes the first fracture to form at one of the poles, where the ice shell is thinnest owing to tidal heating 7. To date, no study simultaneously explains why the tiger stripes should be located only at the south pole, why there are multiple approximately parallel and regularly spaced fractures, what accounts for their spacing of about 35 km, and why similarly active fissures have not been observed on other icy bodies.

#Enceladus tiger stripes tidal heating series

We predict that the tiger-stripe regions with highest relative temperatures will be the lower-latitude branch of Damascus, Cairo around 60 degrees W longitude and Alexandria around 150 degrees W longitude.Active eruptions from the south polar region of Saturn’s ~500-km-diameter moon Enceladus are concentrated along a series of lineaments known as the ‘tiger stripes’ 1, 2, thought to be partially open fissures that connect to the liquid water ocean beneath the ice shell 3, 4. The tidal displacements required imply a Love number of h2 > 0.01, suggesting that the ice shell is decoupled from the silicate interior by a subsurface ocean. The ice shell thickness needed to produce the observed heat flux is at least 5 km. Vapour produced by this heating may escape as plumes through cracks reopened by the tidal stresses. Here we show that the most likely explanation for the heat and vapour production is shear heating by tidally driven lateral (strike-slip) fault motion with displacement of approximately 0.5 m over a tidal period. Neither model addresses how delivery of internal heat to the near-surface is sustained. The plume characteristics and local high heat flux have been ascribed either to the presence of liquid water within a few tens of metres of the surface, or the decomposition of clathrates. Enceladus, a small icy satellite of Saturn, has active plumes jetting from localized fractures ('tiger stripes') within an area of high heat flux near the south pole.