Independent evolution of stratospheric temperatures in Jupiter's northern and southern auroral regions from 2014 to 2016

Sinclair, James; Orton, Glenn S.; Greathouse, Thomas; Fletcher, Leigh N.; Tao, Chihiro; Gladstone, G. R.; Adriani, A.; Dunn, W. R.; Moses, J. I.; Hue, V.; Irwin, Patrick; Melin, Henrik; Giles, Rohini

doi:10.1002/2017gl073529

Cited by 13 publications

(13 citation statements)

References 37 publications

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“…Another effect of the downward motions would be adiabatic heating around the vortex break-up level. Heating at the millibar level was observed inside both ovals by Sinclair et al (2017) and could be an indication that this is actually the level at which the vortices break up. We note that the independence of this heating with respect to solar illumination conditions (Sinclair et al 2017) seems to disqualify aerosol heating as a cause.…”

Section: Discussionmentioning

confidence: 84%

“…Heating at the millibar level was observed inside both ovals by Sinclair et al (2017) and could be an indication that this is actually the level at which the vortices break up. We note that the independence of this heating with respect to solar illumination conditions (Sinclair et al 2017) seems to disqualify aerosol heating as a cause. We see a sharp HCN emission increase in our data at the edges of the oval, and it could indeed be proof of such heating between the oval and its surrounding region.…”

Section: Discussionmentioning

confidence: 84%

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First direct measurement of auroral and equatorial jets in the stratosphere of Jupiter

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Benmahi

Hue

et al. 2021

A&A

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Context. The tropospheric wind pattern in Jupiter consists of alternating prograde and retrograde zonal jets with typical velocities of up to 100 m s−1 around the equator. At much higher altitudes, in the ionosphere, strong auroral jets have been discovered with velocities of 1−2 km s−1. There is no such direct measurement in the stratosphere of the planet. Aims. In this Letter, we bridge the altitude gap between these measurements by directly measuring the wind speeds in Jupiter’s stratosphere. Methods. We use the Atacama Large Millimeter/submillimeter Array’s very high spectral and angular resolution imaging of the stratosphere of Jupiter to retrieve the wind speeds as a function of latitude by fitting the Doppler shifts induced by the winds on the spectral lines. Results. We detect, for the first time, equatorial zonal jets that reside at 1 mbar, that is, above the altitudes where Jupiter’s quasi-quadrennial oscillation occurs. Most noticeably, we find 300−400 m s−1 nonzonal winds at 0.1 mbar over the polar regions underneath the main auroral ovals. They are in counterrotation and lie several hundred kilometers below the ionospheric auroral winds. We suspect them to be the lower tail of the ionospheric auroral winds. Conclusions. We directly detect, for the first time, strong winds in Jupiter’s stratosphere. They are zonal at low-to-mid latitudes and nonzonal at polar latitudes. The wind system found at polar latitudes may help increase the efficiency of chemical complexification by confining the photochemical products in a region of large energetic electron precipitation.

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Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 84%

First direct measurement of auroral and equatorial jets in the stratosphere of Jupiter

Cavalié

Benmahi

Hue

et al. 2021

A&A

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“…This is possible with several ongoing studies of Io and the Io torus that are cross referenced with the work presented here in a full description of Juno‐supporting observations that are summarized at a Web site maintained by the Juno mission: https://www.missionjuno.swri.edu/planned-observations. A more complete picture of the processes of energy transport associated with auroral phenomena and their evolution in time can be obtained by additional cross referencing of X‐ray emission (e.g., Dunn et al, ), auroral emission from H 3 + in the near infrared from the Jupiter Infrared Auroral Mapper among Juno's instrumentation (e.g., Mura et al, ), and supporting ground‐based observations of H 3 + emission (e.g., L. Moore, et al, ) and their associated influence on temperatures of Jupiter's upper stratosphere (e.g., Sinclair et al, ). The timing and scope of these observations are also summarized on the Juno‐maintained Web site listed above.…”

Section: Discussionmentioning

confidence: 90%

Jupiter's Aurora Observed With HST During Juno Orbits 3 to 7

et al. 2018

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A large set of observations of Jupiter's ultraviolet aurora was collected with the Hubble Space Telescope concurrently with the NASA‐Juno mission, during an eight‐month period, from 30 November 2016 to 18 July 2017. These Hubble observations cover Juno orbits 3 to 7 during which Juno in situ and remote sensing instruments, as well as other observatories, obtained a wealth of unprecedented information on Jupiter's magnetosphere and the connection with its auroral ionosphere. Jupiter's ultraviolet aurora is known to vary rapidly, with timescales ranging from seconds to one Jovian rotation. The main objective of the present study is to provide a simplified description of the global ultraviolet auroral morphology that can be used for comparison with other quantities, such as those obtained with Juno. This represents an entirely new approach from which logical connections between different morphologies may be inferred. For that purpose, we define three auroral subregions in which we evaluate the auroral emitted power as a function of time. In parallel, we define six auroral morphology families that allow us to quantify the variations of the spatial distribution of the auroral emission. These variations are associated with changes in the state of the Jovian magnetosphere, possibly influenced by Io and the Io plasma torus and by the conditions prevailing in the upstream interplanetary medium. This study shows that the auroral morphology evolved differently during the five ~2 week periods bracketing the times of Juno perijove (PJ03 to PJ07), suggesting that during these periods, the Jovian magnetosphere adopted various states.

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“…In general, the hydrocarbon eddy diffusion coefficient in Jupiter's auroral region is poorly known and our state of knowledge is based on modeling and limited results from the He 584 Å emissions. Future analysis of Juno, Hisaki, and HST data sets and ground‐based infrared support (e.g., Sinclair et al, , and references therein) in combination with physical models are needed to further our understanding of this complex region.…”

Section: Discussionmentioning

confidence: 99%

Precipitating Electron Energy Flux and Characteristic Energies in Jupiter's Main Auroral Region as Measured by Juno/JEDI

et al. 2018

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The relationship between electron energy flux and the characteristic energy of electron distributions in the main auroral loss cone bridges the gap between predictions made by theory and measurements just recently available from Juno. For decades such relationships have been inferred from remote sensing observations of the Jovian aurora, primarily from the Hubble Space Telescope, and also more recently from Hisaki. However, to infer these quantities, remote sensing techniques had to assume properties of the Jovian atmospheric structure—leading to uncertainties in their profile. Juno's arrival and subsequent auroral passes have allowed us to obtain these relationships unambiguously for the first time, when the spacecraft passes through the auroral acceleration region. Using Juno/Jupiter Energetic particle Detector Instrument (JEDI), an energetic particle instrument, we present these relationships for the 30‐keV to 1‐MeV electron population. Observations presented here show that the electron energy flux in the loss cone is a nonlinear function of the characteristic or mean electron energy and supports both the predictions from Knight (1973, https://doi.org/10.1016/0032-0633(73)90093-7) and magnetohydrodynamic turbulence acceleration theories (e.g., Saur et al., 2003, https://doi.org/10.1029/2002GL015761). Finally, we compare the in situ analyses of Juno with remote Hisaki observations and use them to help constrain Jupiter's atmospheric profile. We find a possible solution that provides the best agreement between these data sets is an atmospheric profile that more efficiently transports the hydrocarbons to higher altitudes. If this is correct, it supports the previously published idea (e.g., Parkinson et al., 2006, https://doi.org/10.1029/2005JE002539) that precipitating electrons increase the hydrocarbon eddy diffusion coefficients in the auroral regions.

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Independent evolution of stratospheric temperatures in Jupiter's northern and southern auroral regions from 2014 to 2016

Cited by 13 publications

References 37 publications

First direct measurement of auroral and equatorial jets in the stratosphere of Jupiter

First direct measurement of auroral and equatorial jets in the stratosphere of Jupiter

Jupiter's Aurora Observed With HST During Juno Orbits 3 to 7

Precipitating Electron Energy Flux and Characteristic Energies in Jupiter's Main Auroral Region as Measured by Juno/JEDI

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