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An observed correlation between plume activity and tidal stresses on Enceladus
M M Hedman1, C M Gosmeyer, P D Nicholson
1Center for Radiophysics and Space Research, Cornell University, Ithaca, New York 14853, USA. mmhedman@astro.cornell.edu
Nature
|August 2, 2013
Summary
Saturn's moon Enceladus expels more ice and water vapor when furthest from Saturn, suggesting tidal forces widen its fissures. This geological activity correlates with orbital position, impacting plume brightness.
Area of Science:
- Planetary Science
- Geophysics
- Astrobiology
Background:
- Enceladus, a moon of Saturn, exhibits geysers erupting water vapor and ice particles from its south pole.
- This geological activity is hypothesized to be influenced by tidal stresses from Saturn due to Enceladus' eccentric orbit.
Purpose of the Study:
- To investigate the relationship between Enceladus' orbital position and its plume activity.
- To explore the role of tidal stresses in controlling the geyser's heat and material flux.
Main Methods:
- Analysis of the horizontally integrated brightness of Enceladus' plume.
- Correlation of plume brightness variations with Enceladus' orbital position (apocentre and pericentre).
Main Results:
- Plume brightness is significantly higher when Enceladus is at apocentre (farthest from Saturn) compared to pericentre (closest approach).
- Increased plume activity at apocentre aligns with geophysical models predicting wider fissures under tension.
Conclusions:
- Tidal stresses, modulated by orbital eccentricity, likely play a crucial role in driving Enceladus' plume activity.
- The findings support the hypothesis that varying tidal forces control the opening and closing of fissures, influencing material expulsion from Enceladus' subsurface.
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