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| Open AccessDouble superionicity in icy compounds at planetary interior conditions
At high pressures, water and ammonia are known to exhibit superionic states. Here it is shown that many planetary ices (H-C-N-O compounds) exhibit a superionic state, and in some cases, a doubly superionic state, in which multiple elements diffuse simultaneously.
- Kyla de Villa
- , Felipe González-Cataldo
- & Burkhard Militzer
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Article
| Open AccessDrifting discrete Jovian radio bursts reveal acceleration processes related to Ganymede and the main aurora
Jovian short bursts (S-bursts) are induced by the Io-Jupiter interaction. Here, the authors show a drifting radio burst detection method and report S-bursts related to Ganymede-Jupiter interaction and to Jovian aurora.
- Emilie Mauduit
- , Philippe Zarka
- & Sébastien L. G. Hess
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| Open AccessLightning at Jupiter pulsates with a similar rhythm as in-cloud lightning at Earth
Potential similarities between Jovian and Earth lightning are helpful to understand involved properties. Here, the authors show that the Jovian lightning initiation processes are similar to those of intracloud lightning at Earth.
- Ivana Kolmašová
- , Ondřej Santolík
- & Radek Lán
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Article
| Open AccessMagnesium oxide-water compounds at megabar pressure and implications on planetary interiors
Magnesium Oxide and water are abundant in the interior of planets. Here, the authors predict three new MgO-H2O compounds: Mg2O3H2, MgO3H4 and MgO4H6, and they exhibit superionic behavior in planetary interior conditions.
- Shuning Pan
- , Tianheng Huang
- & Jian Sun
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Article
| Open AccessThermodynamics of diamond formation from hydrocarbon mixtures in planets
This study combines computational chemistry and machine learning to provide insight on whether diamonds can form inside ice giants. This can help explain the dichotomy of Uranus and Neptune.
- Bingqing Cheng
- , Sebastien Hamel
- & Mandy Bethkenhagen
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| Open AccessJuno spacecraft gravity measurements provide evidence for normal modes of Jupiter
Juno spacecraft experienced unknown accelerations near the closest approach to Jupiter. Here, the authors show that Jupiter’s axially symmetric, north-south asymmetric gravity field measured by Juno is perturbed by a time-variable component, associated to internal oscillations.
- Daniele Durante
- , Tristan Guillot
- & Scott J. Bolton
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| Open AccessFormation of ammonia–helium compounds at high pressure
Helium is generally considered too inert to be present in giant ice planet mantles. The authors, by first-principles calculations and crystal structure searches, find stable ammonia–helium compounds at the conditions of Uranus and Neptune’s upper mantles, with possible implications in the planet composition models.
- Jingming Shi
- , Wenwen Cui
- & Yinwei Li
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| Open AccessNumerical simulations help revealing the dynamics underneath the clouds of Jupiter
Since its arrival at Jupiter in 2016, NASA’s Juno spacecraft has been performing high-precision measurement of the gravity and magnetic fields. When combined with numerical simulations, they provide a unique window to the dynamics in the planet’s deep atmosphere.
- Johannes Wicht
- & Thomas Gastine
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Article
| Open AccessMultilayer hazes over Saturn’s hexagon from Cassini ISS limb images
The authors analyze a system of multi-layered hazes above Saturn’s hexagonal-wave cloud tops in the visual range. Analyses suggest the formation to be caused by condensation processes, and the vertical distribution of stacked layers by the upward propagation of internal gravity waves.
- A. Sánchez-Lavega
- , A. García-Muñoz
- & J. Peralta
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| Open AccessFormation of electron radiation belts at Saturn by Z-mode wave acceleration
Radial diffusion is the only mechanism considered to accelerate trapped electrons to relativistic energies in Saturn’s magnetic field, forming radiation belts. Here the authors show another mechanism, electron acceleration via Doppler shifted cyclotron resonant interaction with Z-mode waves, which can form radiation belts inside the orbit of Enceladus.
- E. E. Woodfield
- , R. B. Horne
- & W. S. Kurth
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| Open AccessLess absorbed solar energy and more internal heat for Jupiter
Radiant energy budgets and internal heat play a key role in the evolution of planets. Here, the authors analyze data from the Cassini mission to show that Jupiter’s radiant energy and internal heat budgets are significantly larger than previous estimates.
- Liming Li
- , X. Jiang
- & R. W. Schmude Jr.
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| Open AccessA hexagon in Saturn’s northern stratosphere surrounding the emerging summertime polar vortex
The Cassini spacecraft has provided an unprecedented characterisation of seasonal changes on Saturn. Here the authors describe the development of a warm polar vortex in Saturn’s northern summer, and show that the hexagon extends hundreds of kilometres from the troposphere into the stratosphere.
- L. N. Fletcher
- , G. S. Orton
- & S. B. Calcutt
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| Open AccessStrong whistler mode waves observed in the vicinity of Jupiter’s moons
Observations of Jupiter’s magnetosphere provide opportunities to understand how magnetic fields interact with particles. Here, the authors report that the chorus wave power is increased in the vicinity of Europa and Ganymede. The generated waves are able to accelerate particles to very high energy.
- Y. Y. Shprits
- , J. D. Menietti
- & D. A. Gurnett
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| Open AccessAn enduring rapidly moving storm as a guide to Saturn’s Equatorial jet’s complex structure
The origin, variability, and structure of Saturn’s intense and broad eastward equatorial jet at upper cloud level are complex and unexplained. Here, based on observations of a large, bright equatorial disturbance in 2015, the authors characterise the vertical structure of the jet and its long-term variability.
- A. Sánchez-Lavega
- , E. García-Melendo
- & T. Barry