Auroral hot spots are observed across the Universe at different scales1 and mark the coupling between a surrounding plasma environment and an atmosphere. Within our own Solar System, Jupiter possesses the only resolvable example of this large-scale energy transfer. Jupiter’s northern X-ray aurora is concentrated into a hot spot, which is located at the most poleward regions of the planet’s aurora and pulses either periodically2,3 or irregularly4,5. X-ray emission line spectra demonstrate that Jupiter’s northern hot spot is produced by high charge-state oxygen, sulfur and/or carbon ions with an energy of tens of MeV (refs 4,5,6) that are undergoing charge exchange. Observations instead failed to reveal a similar feature in the south2,3,7,8. Here, we report the existence of a persistent southern X-ray hot spot. Surprisingly, this large-scale southern auroral structure behaves independently of its northern counterpart. Using XMM-Newton and Chandra X-ray campaigns, performed in May–June 2016 and March 2007, we show that Jupiter’s northern and southern spots each exhibit different characteristics, such as different periodic pulsations and uncorrelated changes in brightness. These observations imply that highly energetic, non-conjugate magnetospheric processes sometimes drive the polar regions of Jupiter’s dayside magnetosphere. This is in contrast to current models of X-ray generation for Jupiter9,10. Understanding the behaviour and drivers of Jupiter’s pair of hot spots is critical to the use of X-rays as diagnostics of the wide range of rapidly rotating celestial bodies that exhibit these auroral phenomena.
Access optionsAccess options
Subscribe to Journal
Get full journal access for 1 year
only $8.67 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Hallinan, G. et al. Magnetospherically driven optical and radio aurorae at the end of the stellar main sequence. Nature 523, 568–571 (2015).
Gladstone, G. R. et al. A pulsating auroral X-ray hot spot on Jupiter. Nature 415, 1000–1003 (2002).
Dunn, W. R. et al. The impact of an ICME on the Jovian X-ray aurora. J. Geophys. Res. A Space Phys. 121, 2274–2307 (2016).
Branduardi-Raymont, G. et al. A study of Jupiter’s aurorae with XMM-Newton. Astron. Astrophys. 463, 761–774 (2007).
Elsner, R. F. et al. Simultaneous Chandra X ray Hubble Space Telescope ultraviolet, and Ulysses radio observations of Jupiter’s aurora. J. Geophys. Res. Space Phys. 110, 1–16 (2005).
Kharchenko, V., Bhardwaj, A., Dalgarno, A., Schultz, D. R. & Stancil, P. C. Modeling spectra of the north and south Jovian X-ray auroras. J. Geophys. Res. Space Phys. 113, 1–11 (2008).
Branduardi-Raymont, G. et al. Spectral morphology of the X-ray emission from Jupiter’s aurorae. J. Geophys. Res. Space Phys. 113, 1–11 (2008).
Kimura, T. et al. Jupiter’s X-ray and EUV auroras monitored by Chandra, XMM-Newton, and Hisaki satellite. J. Geophys. Res. Space Phys. 121, 2308–2320 (2016).
Bunce, E. J., Cowley, S. W. H. & Yeoman, T. K. Jovian cusp processes: Implications for the polar aurora. J. Geophys. Res. Space Phys. 109, 1–26 (2004).
Cravens, T. E. et al. Implications of Jovian X-ray emission for magnetosphere-ionosphere coupling. J. Geophys. Res. Space Phys. 108, 1–12 (2003).
Cowley, S. W. H. & Bunce, E. J. Origin of the main auroral oval in Jupiter’s coupled magnetosphere-ionosphere system. Planet. Space Sci. 49, 1067–1088 (2001).
Grodent, D. et al. Auroral evidence of a localized magnetic anomaly in Jupiter’s northern hemisphere. J. Geophys. Res. Space Phys. 113, 1–10 (2008).
Vogt, M. F. et al. Improved mapping of Jupiter’s auroral features to magnetospheric sources. J. Geophys. Res. Space Phys. 116, 1–24 (2011).
Connerney, J. E. P., Acuña, M. H., Ness, N. F. & Satoh, T. New models of Jupiter’s magnetic field constrained by the Io flux tube footprint. J. Geophys. Res. 103, 11929–11939 (1998).
Waite, J. H. et al. ROSAT observations of the Jupiter aurora. J. Geophys. Res. 99, 799–809 (1994).
Joy, S. P. et al. Probabilistic models of the Jovian magnetopause and bow shock locations. J. Geophys. Res. Space Phys. 107, 1–17 (2002).
Bagenal, F. Empirical model of the Io plasma torus: Voyager measurements. J. Geophys. Res. 99, 11043 (1994).
Meredith, C. J., Cowley, S. W. H., Hansen, K. C., Nichols, J. D. & Yeoman, T. K. Simultaneous conjugate observations of small-scale structures in Saturn’s dayside ultraviolet auroras: implications for physical origins. J. Geophys. Res. Space Phys. 118, 2244–2266 (2013).
McComas, D. J. & Bagenal, F. Jupiter: a fundamentally different magnetospheric interaction with the solar wind. Geophys. Res. Lett. 34, 1–5 (2007).
Cowley, S. W. H., Badman, S. V., Imber, S. M. & Milan, S. E. Comment on ‘Jupiter: a fundamentally different magnetospheric interaction with the solar wind’ by D. J. McComas and F. Bagenal. Geophys. Res. Lett. 35, 1–3 (2008).
Desroche, M., Bagenal, F., Delamere, P. A. & Erkaev, N. Conditions at the expanded Jovian magnetopause and implications for the solar wind interaction. J. Geophys. Res. Space Phys. 117, 1–18 (2012).
Lockwood, M. & Moen, J. Reconfiguration and closure of lobe flux by reconnection during northward IMF: possible evidence for signatures in cusp/cleft auroral emissions. Ann. Geophys. 17, 996–1011 (1999).
Fuselier, S. A., Trattner, K. J., Petrinec, S. M. & Lavraud, B. Dayside magnetic topology at the Earth’s magnetopause for northward IMF. J. Geophys. Res. Space Phys. 117, 1–14 (2012).
Delamere, P. A. & Bagenal, F. Solar wind interaction with Jupiter’s magnetosphere. J. Geophys. Res. Space Phys. 115, 1–20 (2010).
Mann, I. R. et al. Coordinated ground-based and Cluster observations of large amplitude global magnetospheric oscillations during a fast solar wind speed interval. Ann. Geophys. 20, 405–426 (2002).
Rae, I. J. et al. Evolution and characteristics of global Pc5 ULF waves during a high solar wind speed interval. J. Geophys. Res. Space Phys. 110, 1–16 (2005).
Khurana, K. K. & Kivelson, M. G. Ultralow frequency MHD waves in Jupiter’s middle magnetosphere. J. Geophys. Res. 94, 5241 (1989).
Wilson, R. J. & Dougherty, M. K. Evidence provided by galileo of ultra low frequency waves within Jupiter’s middle magnetosphere. Geophys. Res. Lett. 27, 835–838 (2000).
Hasegawa, H. et al. Transport of solar wind into Earth’s magnetosphere through rolled-up Kelvin–Helmholtz vortices. Nature 430, 755–758 (2004).
Ma, X., Stauffer, B., Delamere, P. A. & Otto, A. Asymmetric Kelvin–Helmholtz propagation at Saturn’s dayside magnetopause. J. Geophys. Res. Space Phys. 120, 1867–1875 (2015).
Bonfond, B. et al. Quasi-periodic polar flares at Jupiter: a signature of pulsed dayside reconnections? Geophys. Res. Lett. 38, 1–5 (2011).
Nichols, J. D. et al. Response of Jupiter’s auroras to conditions in the interplanetary medium as measured by the Hubble Space Telescope and Juno. Geophys. Res. Lett. 44, 7643–7652 (2017).
Sinclair, J. A. et al. Independent evolution of stratospheric temperatures in Jupiter’s northern and southern auroral regions from 2014 to 2016. Geophys. Res. Lett. 44, 5345–5354 (2017).
Branduardi-Raymont, G., Elsner, R. F., Gladstone, G. R. & Ramsay, G. First observation of Jupiter by XMM-Newton. Astron. Astrophys. 337, 331–337 (2004).
Hui, Y. et al. Comparative analysis and variability of the Jovian X-ray spectra detected by the Chandra and XMM-Newton observatories. J. Geophys. Res. Space Phys. 115, A07102 (2010).
Branduardi-raymont, G. et al. Thermal and non-thermal components of the X-ray emission from Jupiter. Progr. Theor. Exp. Phys. 169, 75–78 (2007).
Branduardi-Raymont, G. et al. Latest results on Jovian disk X-rays from XMM-Newton. Planet. Space Sci. 55, 1126–1134 (2007).
Phillips, K. J. H. et al. Solar flare X-ray spectra from the Solar Maximum Mission Flat Crystal Spectrometer. Astrophys. J. 256, 774–787 (1982).
Bhardwaj, A. et al. Solar control on Jupiter’s equatorial X-ray emissions: 26–29 November 2003 XMM-Newton observation. Geophys. Res. Lett. 32, 1–5 (2005).
Bhardwaj, A. et al. Low- to middle-latitude X-ray emission from Jupiter. J. Geophys. Res. Space Phys. 111, 1–16 (2006).
Selke, T., Bayarri, J. J. & Berger, J. O. Calibration of p-values for testing precise hypotheses. Am. Stat. 55, 62–71 (2001).
Allen, R. Automatic phase pickers: their present use and future prospects. Bull. Seismol. Soc. Am. 72, S225–242 (1982).
Leahy, D. A. et al. On searches for pulsed emission with application to four globular cluster X-ray sources—NGC 1851, 6441, 6624, and 6712. Astrophys. J. 266, 160–170 (1983).
W.R.D. thanks N. Achilleos and R. Gray for discussions on Jovian X-rays, J.-U. Ness and R. Gonzalez-Riestra for extensive help with XMM-Newton observations, and particularly P. Rodriguez for assistance in re-framing them to Jupiter-centred coordinates. We also thank S. Badman, B. Bonfond, E. Chané, G. Clark, P. Delamere, R. Ebert, H. Hasegawa, S. Imber, E. Kronberg, P. Lourn, W. Kurth, A. Masters, J. Nichols, A. Otto, C. Paranicas, A. Radioti, J. Reed, E. Roussos, A. Smith and C. Tao for conversations on Jupiter’s aurora at the Vogt/Masters and Jackman/Paranicas ISSI team meetings. W.R.D. is supported by a Science and Technology Facilities Council (STFC) research grant to University College London (UCL), an SAO fellowship to Harvard-Smithsonian Centre for Astrophysics and by European Space Agency (ESA) contract no. 4000120752/17/NL/MH. I.J.R., G.H.J., G.B.-R. and A.J.C. are supported by STFC Consolidated Grant ST/N000722/1 to the Mullard Space Science Laboratory (MSSL). I.J.R. is supported by NERC grants NE/L007495/1, NE/P017150/1 and NE/P017185/1. G.A.G. is supported by a UCL IMPACT studentship and ESA. C.M.J. is supported by a STFC Ernest Rutherford Fellowship ST/L004399/1. M.F.V. is supported by the US National Science Foundation under Award No. 1524651. Z.Y. is a Marie-Curie COFUND postdoctoral fellow at the University of Liege, co-funded by the European Union. G.R.G. thanks Smithsonian Astrophysical Observatory for award GO6-17001A to the Southwest Research Institute. J.A.S. and G.S.O. acknowledge support from NASA to the Jet Propulsion Laboratory, California Institute of Technology. R.C.-C. acknowledges support from Universidad Pontificia Comillas de Madrid-ICAI and Universidad Complutense de Madrid-Facultad de Informática This work is based on observations from the NASA Chandra X-ray Observatory (Observations 18608, 18609 and archival observation 8219) made possible through the HRC grant (NAS8-03060) and observations from the XMM-Newton Observatory (Observations 0781830301 and 0781830601). We thank the Chandra and XMM-Newton Projects for their support in setting up the observations
Electronic supplementary material
Supplementary Tables 1–8, Supplementary Figures 1–5 (distributed in 6 thematic Supplementary Sections); and Supplementary References 1–15 (only used in the Supplementary Information)
About this article
Nature Astronomy (2019)
Nature Astronomy (2017)