Enceladus

Dynamics Of Geysers And Tracer Transport Over The South Pole Of Enceladus

By Keith Cowing
astro-ph.EP
May 31, 2022
Filed under
Dynamics Of Geysers And Tracer Transport Over The South Pole Of Enceladus
Snapshot taken at the end of the simulation for the S30c90v scenario. Panel (a) shows the temperature anomalies at a given ???? in shading and density anomalies in contours. Solid contour denote positive density anomaly and dashed contours denote negative density anomaly. From thin to thick, contours mark Δ???? = ±10−4 , ±8 × 10−4 kg/m3 , ±5 × 10−3 kg/m3 , ±5 × 10−2 kg/m3 . Panel (b) is similar to panel (a) except salinity is shown in place of temperature. Panel (c,d) shows the freezing/melting rate and heat budget of the ice shell, respectively. In panel (d), red, orange, green and black curves, respectively, represent the ice dissipation Hice, the heat absorbed from the ocean Hocn, the conductive heat loss through the ice Hcond and the latent heat release Hlatent. The gray dashed curve shows the residue of the heat budget, which should be close to zero. Panel (e,f) show the dynamics in a horizontal plane, horizontal flow speeds in quivers, density anomaly in the shading, and areas with vertical speed beyond a certain threshold (see text just above the figure) are marked by hatches. Green hatches denote upward motions and yellow hatches denote downward motions. The plane shown by panel (e) is taken just below the ice shell (z=-9km), and the plane shown by panel (f) is just above the seafloor (z=-56km).

Over the south pole of Enceladus, an icy moon of Saturn, geysers eject water into space in a striped pattern, making Enceladus one of the most attractive destinations in the search for extraterrestrial life.

We explore the ocean dynamics and tracer/heat transport associated with geysers as a function of the assumed salinity of the ocean and various core-shell heat partitions and bottom heating patterns.

We find that, even if heating is concentrated into a narrow band on the seafloor directly beneath the south pole, the warm fluid becomes quickly mixed with its surroundings due to baroclinic instability.

The warming signal beneath the ice is diffuse and insufficient to prevent the geyser from freezing over. Instead, if heating is assumed to be local to the geyser, emanating from tidal dissipation in the ice itself, the geyser can be sustained.

In this case, the upper ocean beneath the ice becomes stably stratified and thus a barrier to vertical communication, leading to transit timescales from the core to the ice shell of hundreds of years.

Wanying Kang, John Marshall, Tushar Mittal, Suyash Bire

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2205.15732 [astro-ph.EP] (or arXiv:2205.15732v1 [astro-ph.EP] for this version)
Submission history
From: Wanying Kang
[v1] Tue, 31 May 2022 12:23:11 UTC (35,461 KB)
https://arxiv.org/abs/2205.15732
Astrobiology

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