Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures

Abstract

The icy surface of Jupiter’s moon, Europa, is thought to lie on top of a global ocean1,2,3,4. Signatures in some Hubble Space Telescope images have been associated with putative water plumes rising above Europa’s surface5,6, providing support for the ocean theory. However, all telescopic detections reported were made at the limit of sensitivity of the data5,6,7, thereby calling for a search for plume signatures in in-situ measurements. Here, we report in-situ evidence of a plume on Europa from the magnetic field and plasma wave observations acquired on Galileo’s closest encounter with the moon. During this flyby, which dropped below 400 km altitude, the magnetometer8 recorded an approximately 1,000-kilometre-scale field rotation and a decrease of over 200 nT in field magnitude, and the Plasma Wave Spectrometer9 registered intense localized wave emissions indicative of a brief but substantial increase in plasma density. We show that the location, duration and variations of the magnetic field and plasma wave measurements are consistent with the interaction of Jupiter’s corotating plasma with Europa if a plume with characteristics inferred from Hubble images were erupting from the region of Europa’s thermal anomalies. These results provide strong independent evidence of the presence of plumes at Europa.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Galileo MAG data for the E12 flyby.
Fig. 2: Galileo plasma wave data and derived plasma density for the E12 flyby.
Fig. 3: Location of the modelled plume on Europa’s surface.

Similar content being viewed by others

References

  1. Khurana, K. K. et al. Induced magnetic fields as evidence for subsurface oceans in Europa and Callisto. Nature 395, 777–780 (1998).

    Article  ADS  Google Scholar 

  2. Carr, M. H. et al. Evidence for a subsurface ocean on Europa. Nature 391, 363–365 (1998).

    Article  ADS  Google Scholar 

  3. Pappalardo, R. T. et al. Does Europa have a subsurface ocean? Evaluation of the geological evidence. J. Geophys. Res. 104, 24105–24055 (1999).

    Article  ADS  Google Scholar 

  4. Kivelson, M. G. et al. Galileo magnetometer measurements strengthen the case for a subsurface ocean at Europa. Science 289, 1340–1343 (2000).

    Article  ADS  Google Scholar 

  5. Roth, L. et al. Transient water vapor at Europa’s south pole. Science 343, 171–174 (2014).

    Article  ADS  Google Scholar 

  6. Sparks, W. B. et al. Probing for evidence of plumes on Europa with HST/STIS. Astrophys. J. 829, 121 (2016).

    Article  ADS  Google Scholar 

  7. Sparks, W. B. et al. Active cryovolcanism on Europa? Astrophys. J. Lett. 839, L18 (2017).

    Article  ADS  Google Scholar 

  8. Kivelson, M. G., Khurana, K. K., Means, J. D., Russell, C. T. & Snare, R. C. The Galileo magnetic field investigation. Space Sci. Rev. 60, 357–383 (1992).

    Article  ADS  Google Scholar 

  9. Gurnett, D. A. et al. The Galileo plasma wave investigation. Space Sci. Rev. 60, 341–355 (1992).

    Article  ADS  Google Scholar 

  10. Roth, L. et al. Orbital apocenter is not a sufficient condition for HST/STIS detection of Europa’s water vapor aurora. Proc. Natl Acad. Sci. USA 111, E5123–E5132 (2014).

    Article  ADS  Google Scholar 

  11. Spencer, J. R., Tamppari, L. K., Martin, T. Z. & Travis, L. D. Temperatures on Europa from Galileo photopolarimeter-radiometer: nighttime thermal anomalies. Science 284, 1514–1516 (1999).

    Article  ADS  Google Scholar 

  12. McGrath, M. & Sparks, W. B. Galileo ionosphere profile coincident with repeat plume detection location at Europa. Res. Notes AAS 1, 14 (2017).

    Article  Google Scholar 

  13. Blöcker, A., Saur, J. & Roth, L. Europa’s plasma interaction with an inhomogeneous atmosphere: development of Alfvén winglets within the Alfvén wings. J. Geophys. Res. 121, 9794–9828 (2016).

    Article  Google Scholar 

  14. Kurth, W. S. et al. The plasma wave environment of Europa. Planet. Space Sci. 49, 345–363 (2001).

    Article  ADS  Google Scholar 

  15. Kivelson, M. G., Khurana, K. K. & Volwerk, M. in Europa (eds Pappalardo, R. T., McKinnon, W. B. & Khurana, K. K.) 545–570 (Univ. Arizona Press, Tucson, AZ, 2009).

  16. Toth, G. et al. Adaptive numerical algorithms in space weather modeling. J. Comp. Phys. 231, 870–903 (2012).

    Article  ADS  MathSciNet  Google Scholar 

  17. Rubin, M. et al. Self-consistent multi-fluid MHD simulations of Europa’s exospheric interaction with Jupiter’s magnetosphere. J. Geophys. Res. 120, 3503–3524 (2015).

    Article  Google Scholar 

  18. Hall, D. T., Strobel, D. F. & Feldman, P. D., McGrath, M. A. & Weaver, H. A. Detection of an oxygen atmosphere on Jupiter’s moon Europa. Nature 373, 677–679 (1995).

    Article  ADS  Google Scholar 

  19. Bagenal, F., Dougherty, L. P., Bodish, K. M., Richardson, J. D. & Belcher, J. M. Survey of Voyager plasma science ions at Jupiter: 1. Analysis method. J. Geophys. Res. 122, 8241–8256 (2017).

    Article  Google Scholar 

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

    Article  ADS  Google Scholar 

  21. Neubauer, F. M. The sub-Alfvénic interaction of the Galilean satellites with the Jovian magnetosphere. J. Geophys. Res. 103, 19843–19866 (1998).

    Article  ADS  Google Scholar 

  22. Grasset, O. et al. JUpiter ICy moons Explorer (JUICE): an ESA mission to orbit Ganymede and to characterise the Jupiter system. Planet. Space Sci. 78, 1–21 (2013).

    Article  ADS  Google Scholar 

  23. Pappalardo, R. et al. Science objectives and capabilities of the NASA Europa mission. In Proc. 47th Lunar and Planetary Science Conf. 3058 (Lunar and Planetary Institute, 2016).

  24. Powell, K. G., Roe, P. L., Linde, T. J., Gombosi, T. I. & De Zeeuw, D. L. A solution-adaptive upwind scheme for ideal magnetohydrodynamics. J. Comp. Phys. 154, 284–309 (1999).

    Article  ADS  MathSciNet  MATH  Google Scholar 

  25. Gombosi, T. I. et al. Semirelativistic magnetohydrodynamics and physics-based convergence acceleration. J. Comput. Phys. 177, 176–205 (2002).

    Article  ADS  MathSciNet  MATH  Google Scholar 

  26. Kabin, K. et al. On Europa’s magnetospheric interaction: a MHD simulation of the E4 flyby. J. Geophys. Res. 104, 19983–19992 (1999).

    Article  ADS  Google Scholar 

  27. Liu, Y. et al. Two-species, 3D MHD simulation of Europa’s interaction with Jupiter’s magnetosphere. Geophys. Res. Lett. 27, 1791–1794 (2000).

    Article  ADS  Google Scholar 

  28. Hall, D. T., Feldman, P. D., McGrath, M. A. & Strobel, D. F. The far-ultraviolet oxygen airglow of Europa and Ganymede. Astrophys. J. 499, 475–481 (1998).

    Article  ADS  Google Scholar 

  29. McGrath, M. A., Hansen, C. J. & Hendrix, A. R. in Europa (eds Pappalardo, R. T., McKinnon, W. B. & Khurana, K. K.) 485–505 (Univ. Arizona Press, Tucson, AZ, 2009).

  30. Shematovich, V. I., Johnson, R. E., Cooper, J. F. & Wong, M. C. Surface-bounded atmosphere of Europa. Icarus 173, 480–498 (2005).

    Article  ADS  Google Scholar 

  31. Smyth, W. H. & Marconi, M. L. Europa’s atmosphere, gas tori, and magnetospheric implications. Icarus 181, 510–526 (2006).

    Article  ADS  Google Scholar 

  32. Cassidy, T. A., Johnson, R. E., McGrath, M. A., Wong, M. C. & Cooper, J. F. The spatial morphology of Europa’s near-surface O2 atmosphere. Icarus 191, 755–764 (2007).

    Article  ADS  Google Scholar 

  33. Plainaki, C. et al. The role of sputtering and radiolysis in the generation of Europa exosphere. Icarus 218, 956–966 (2012).

    Article  ADS  Google Scholar 

  34. Saur, J., Strobel, D. F. & Neubauer, F. M. Interaction of the Jovian magnetosphere with Europa: constraints on the neutral atmosphere. J. Geophys. Res. 103, 19947–19962 (1998).

    Article  ADS  Google Scholar 

  35. Johnson, R. E. et al. in Europa (eds Pappalardo, R. T., McKinnon, W. B. & Khurana, K. K.) 507–528 (Univ. Arizona Press, Tucson, AZ, 2009).

  36. Schilling, N., Neubauer, F. M. & Saur, J. Influence of the internally induced magnetic field on the plasma interaction of Europa. J. Geophys. Res. 113, A03203 (2008).

    Article  ADS  Google Scholar 

  37. Dols, V., Bagenal, F., Cassidy, T., Crary, F. J. & Delamere, P. A. Europa’s atmospheric neutral escape: importance of symmetrical O2 charge exchange. Icarus 264, 387–397 (2016).

    Article  ADS  Google Scholar 

  38. Schunk, R. & Nagy, A. Ionospheres: Physics, Plasma Physics, and Chemistry (Cambridge Univ. Press, Cambridge, UK, 2009).

    Book  Google Scholar 

  39. Bagenal, F. et al. Plasma conditions at Europa’s orbit. Icarus 261, 1–13 (2015).

    Article  ADS  Google Scholar 

  40. Zimmer, C., Khurana, K. K. & Kivelson, M. G. Subsurface oceans on Europa and Callisto: constraints from Galileo magnetometer observations. Icarus 147, 329–347 (2000).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We thank M. McGrath for an illuminating presentation at a Europa Clipper Project Science Group meeting on observations of Europa’s plumes, which led us to re-examine the Galileo MAG data on which this paper is largely based. The work at the University of Michigan was supported by NASA through grants #NNX12AM74G and #NNX15AH28G, contract #1532308 through the Jet Propulsion Laboratory and contract #143448 through the Applied Physics Laboratory at Johns Hopkins University. The research at the University of Iowa is supported by NASA through contract UTA16-001080 through the University of Texas at Austin. Additional funding for work at UCLA was provided by NASA grants #NNX13AL05G:000002 and #NNX14AO24G.

Author information

Authors and Affiliations

Authors

Contributions

X.J., M.G.K. and K.K.K. contributed to the analysis of the Galileo magnetic field data. W.S.K. analysed the Galileo plasma wave data. X.J. performed the simulations and led the interpretation of the model results. All authors discussed the results and contributed to writing the manuscript.

Corresponding author

Correspondence to Xianzhe Jia.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figures 1–5.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Jia, X., Kivelson, M.G., Khurana, K.K. et al. Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures. Nat Astron 2, 459–464 (2018). https://doi.org/10.1038/s41550-018-0450-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41550-018-0450-z

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing