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An observed correlation between plume activity and tidal stresses on Enceladus

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Abstract

Saturn’s moon Enceladus emits a plume of water vapour and micrometre-sized ice particles from a series of warm fissures located near its south pole1,2,3,4,5,6,7,8,9,10. This geological activity could be powered or controlled by variations in the tidal stresses experienced by Enceladus as it moves around its slightly eccentric orbit. The specific mechanisms by which these varying stresses are converted into heat, however, are still being debated11,12,13,14,15,16. Furthermore, it has proved difficult to find a clear correlation between the predicted tidal forces and measured temporal variations in the plume’s gas content17,18,19 or the particle flux from individual sources20,21. Here we report that the plume’s horizontally integrated brightness is several times greater when Enceladus is near the point in its eccentric orbit where it is furthest from Saturn (apocentre) than it is when near the point of closest approach to the planet (pericentre). More material therefore seems to be escaping from beneath Enceladus’ surface at times when geophysical models predict its fissures should be under tension12,15,16 and therefore may be wider open.

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Figure 1: Sample VIMS observations of Enceladus and its plume.
Figure 2: Sample vertical profiles of the plume’s brightness.
Figure 3: Variations in the plume’s brightness with phase angle.
Figure 4: Variations in the plume’s corrected brightness with Enceladus’ orbital position.

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References

  1. Spencer, J. R. et al. in Saturn from Cassini-Huygens (eds Dougherty, M. K., Esposito, L. W. & Krimigis, S. M. ) 683–724 (Springer, 2009)

  2. Dougherty, M. K. et al. Identification of a dynamic atmosphere at Enceladus with the Cassini Magnetometer. Science 311, 1406–1409 (2006)

    Article  ADS  CAS  Google Scholar 

  3. Hansen, C. J. et al. Enceladus’ water vapor plume. Science 311, 1422–1425 (2006)

    Article  ADS  CAS  Google Scholar 

  4. Waite, J. H. et al. Cassini Ion and Neutral Mass Spectrometer: Enceladus plume composition and structure. Science 311, 1419–1422 (2006)

    Article  ADS  CAS  Google Scholar 

  5. Porco, C. C. et al. Cassini observes the active south pole of Enceladus. Science 311, 1393–1401 (2006)

    Article  ADS  CAS  Google Scholar 

  6. Ingersoll, A. P. & Ewald, S. P. Total particulate mass in Enceladus plumes and mass of Saturn’s E ring inferred from Cassini ISS images. Icarus 216, 492–506 (2011)

    Article  ADS  Google Scholar 

  7. Hedman, M. M. et al. Spectral observations of the Enceladus plume with Cassini-VIMS. Astrophys. J. 693, 1749–1762 (2009)

    Article  ADS  Google Scholar 

  8. Postberg, F. et al. The E-ring in the vicinity of Enceladus. Icarus 193, 438–454 (2008)

    Article  ADS  CAS  Google Scholar 

  9. Postberg, F., Schmidt, J., Hillier, J., Kempf, S. & Srama, R. A salt-water reservoir as the source of a compositionally stratified plume on Enceladus. Nature 474, 620–622 (2011)

    Article  ADS  CAS  Google Scholar 

  10. Spencer, J. R. et al. Cassini encounters Enceladus: background and the discovery of a south polar hot spot. Science 311, 1401–1405 (2006)

    Article  ADS  CAS  Google Scholar 

  11. Nimmo, F., Spencer, J. R., Pappalardo, R. T. & Mullen, M. E. Shear heating as the origin of the plumes and heat flux on Enceladus. Nature 447, 289–291 (2007)

    Article  ADS  CAS  Google Scholar 

  12. Hurford, T. A., Helfenstein, P., Hoppa, G. V., Greenberg, R. & Bills, B. G. Eruptions arising from tidally controlled periodic openings of rifts on Enceladus. Nature 447, 292–294 (2007)

    Article  ADS  CAS  Google Scholar 

  13. Meyer, J. & Wisdom, J. Tidal heating in Enceladus. Icarus 188, 535–539 (2007)

    Article  ADS  Google Scholar 

  14. Tobie, G., Cadek, O. & Sotin, C. Solid tidal friction above a liquid water reservoir as the origin of the south pole hotspot on Enceladus. Icarus 196, 642–652 (2008)

    Article  ADS  CAS  Google Scholar 

  15. Smith-Konter, B. & Pappalardo, R. T. Tidally driven stress accumulation and shear failure of Enceladus’s tiger stripes. Icarus 198, 435–451 (2008)

    Article  ADS  Google Scholar 

  16. Hurford, T. A. et al. Geological implications of a physical libration on Enceladus. Icarus 203, 541–552 (2009)

    Article  ADS  Google Scholar 

  17. Saur, J. et al. Evidence for temporal variability of Enceladus’ gas jets: modeling of Cassini observations. Geophys. Res. Lett. 35, L20105 (2008)

    Article  ADS  Google Scholar 

  18. Smith, H. T. et al. Enceladus plume variability and the neutral gas densities in Saturn’s magnetosphere. J. Geophys. Res. 115, A10252 (2010)

    Article  ADS  Google Scholar 

  19. Hansen, C. J. et al. The composition and structure of the Enceladus plume. Geophys. Res. Lett. 38, L11202 (2011)

    Article  ADS  Google Scholar 

  20. Porco, C. et al. Jetting activity and thermal emission across the south polar terrain of Enceladus: observations and comparisons with shear-heating models. AGU Fall Meet. Abstr. P13F-02. (2011)

  21. Hurford, T. A., Helfenstein, P. & Spitale, J. N. Tidal control of jet eruptions on Enceladus as observed by Cassini ISS between 2005 and 2007. Icarus 220, 896–903 (2012)

    Article  ADS  Google Scholar 

  22. Brown, R. H. et al. The Cassini Visual and Infrared Mapping Spectrometer (VIMS) investigation. Space Sci. Rev. 115, 111–168 (2004)

    Article  ADS  Google Scholar 

  23. Schmidt, J., Brilliantov, N., Spahn, F. & Kempf, S. Slow dust in Enceladus’ plume from condensation and wall collisions in tiger stripe fractures. Nature 451, 685–688 (2008)

    Article  ADS  CAS  Google Scholar 

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Acknowledgements

We acknowledge the support of the VIMS team, the Cassini project and NASA. This work was supported in part by NASA grant NNX12AC29G. The work of C.M.G. on this project was made possible by the Research Experience for Undergraduates programme at Cornell University.

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Contributions

M.M.H., C.M.G. and P.D.N. performed the data analysis. R.N.C., along with P.D.N., C.S., R.H.B., K.H.B. and B.J.B., planned the observations, and provided the data from the VIMS instrument and the appropriate calibration routines. M.R.S. supported the photometric interpretation of these data. All authors discussed these results.

Corresponding author

Correspondence to M. M. Hedman.

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The authors declare no competing financial interests.

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Hedman, M., Gosmeyer, C., Nicholson, P. et al. An observed correlation between plume activity and tidal stresses on Enceladus. Nature 500, 182–184 (2013). https://doi.org/10.1038/nature12371

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