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Comparing Jupiter's equatorial X-ray emissions with solar X-ray flux over 19 years of the Chandra mission
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  • Seán Christopher McEntee,
  • Caitriona M Jackman,
  • Dale M. Weigt,
  • William Dunn,
  • Vinay Kashyap,
  • Ralph P. Kraft,
  • Corentin Kenelm Louis,
  • Graziella Branduardi-Raymont,
  • Randy Gladstone,
  • Peter Gallagher
Seán Christopher McEntee
Dublin Institute for Advanced Studies, Dublin Institute for Advanced Studies

Corresponding Author:[email protected]

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Caitriona M Jackman
Dublin Institute for Advanced Studies, Dublin Institute for Advanced Studies
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Dale M. Weigt
Dublin Institute for Advanced Studies (DIAS), Dublin Institute for Advanced Studies (DIAS)
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William Dunn
University College London, University College London
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Vinay Kashyap
Smithsonian Astrophysical Observatory (SI), Smithsonian Astrophysical Observatory (SI)
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Ralph P. Kraft
Smithsonian Astrophysical Observatory (SI), Smithsonian Astrophysical Observatory (SI)
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Corentin Kenelm Louis
Dublin Institute for Advanced Studies (DIAS), Dublin Institute for Advanced Studies (DIAS)
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Graziella Branduardi-Raymont
University College London, University College London
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Randy Gladstone
Southwest Research Institute, Southwest Research Institute
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Peter Gallagher
DIAS, DIAS
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Abstract

We present a statistical study of Jupiter’s disk X-ray emissions using 19 years of Chandra X-Ray Observatory (CXO) observations. Previous work has suggested that these emissions are consistent with solar X-rays elastically scattered from Jupiter’s upper atmosphere. We showcase a new Pulse Invariant (PI) filtering method that minimises instrumental effects which may produce unphysical trends in photon counts across the nearly-two-decade span of the observations. We compare the CXO results with solar X-ray flux data from the Geostationary Operational Environmental Satellites (GOES) X-ray Sensor (XRS) for the wavelength band 1-8 Å (long channel), to quantify the correlation between solar activity and jovian disk counts. We find a statistically significant Pearson’s Correlation Coefficient (PCC) of 0.9, which confirms that emitted jovian disk X-rays are predominantly governed by solar activity. We also utilise the high spatial resolution of the High Resolution Camera Instrument (HRC-I) on board the CXO to map the disk photons to their positions on Jupiter’s surface. Voronoi tessellation diagrams were constructed with the JRM09 (Juno Reference Model through Perijove 9) internal field model overlaid to identify any spatial preference of equatorial photons. After accounting for area and scattering across the curved surface of the planet, we find a preference of jovian disk emission at 2-3.5 Gauss surface magnetic field strength. This suggests that a portion of the disk X-rays may be linked to processes other than solar scattering: the spatial preference associated with magnetic field strength may imply increased precipitation from the radiation belts, as previously postulated.
Dec 2022Published in Journal of Geophysical Research: Space Physics volume 127 issue 12. 10.1029/2022JA030971