Jupiter’s upper atmosphere consists of a neutral thermosphere and an electrically charged ionosphere. Astronomers using the NASA/ESA/CSA James Webb Space Telescope have discovered unexpected small-scale intensity features, including arcs, bands, and spots, in the low-latitude ionosphere in the region above Jupiter’s Great Red Spot.
This illustration shows the region observed by Webb, first with its location on the NIRCam image of the entire planet (left), and then the region itself as imaged by Webb’s Near-Infrared Spectrometer (NIRSpec) (right). Image credit: NASA / ESA / CSA / Webb / Jupiter ERS Team / J. Schmidt / H. Melin / M. Zamani, ESA and Webb.
Jupiter is one of the brightest objects in the night sky and can be easily seen on a clear night.
Apart from the bright Northern and Southern Lights at Jupiter’s poles, the glow from Jupiter’s upper atmosphere is weak, making details in this region difficult to discern with ground-based telescopes.
But Webb’s infrared sensitivity has allowed scientists to study the upper atmosphere of the infamous Great Red Spot in unprecedented detail.
The upper atmosphere of this gas giant is the interface between the planet’s magnetic field and the atmosphere below it.
Here you can see the bright and vibrant aurora borealis and southern lights, created by volcanic material erupting from Jupiter’s moon Io.
However, as one approaches the equator, the structure of the planet’s upper atmosphere is influenced by incoming sunlight.
Because Jupiter receives only 4% of the sunlight that Earth does, astronomers predicted that this region would be essentially homogeneous.
Astronomer Henrik Melin of the University of Leicester and his colleagues observed the Great Red Spot in July 2022 using an Integral Field Unit. Webb’s near-infrared spectrometer (NIR Spec).
Their early public science observations aimed to investigate whether this region was in fact dull, and the region above the iconic Great Red Spot was the subject of Webb’s observations.
They were surprised to find that the upper atmosphere contains a variety of complex structures, including dark arcs and bright spots across the entire field of view.
“We probably naively thought this area would be really boring. It’s actually just as interesting, if not more so, than the Northern Lights. Jupiter never fails to surprise us,” Dr Melin said.
The light emitted from this region is driven by sunlight, but the team suggests there must be another mechanism that changes the shape and structure of the upper atmosphere.
“One way this structure can be altered is by gravity waves, similar to how waves crashing on the shore create ripples in the sand,” Dr Melin said.
“These waves originate deep within the turbulent lower atmosphere around the Great Red Spot and can rise in altitude to alter the structure and emissions of the upper atmosphere.”
“These atmospheric waves are occasionally observed on Earth, but they are much weaker than those Webb observed on Jupiter.”
“In the future, we hope to carry out follow-up webbed observations of these complex wave patterns and investigate how they move within the planet’s upper atmosphere to improve our understanding of the energy budget of this region and how its features change over time.”
of Investigation result Published in a journal Natural Astronomy.
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H. Melin othersIrregularities in Jupiter’s ionosphere observed by JWST. Nat AstronPublished online June 21, 2024, doi: 10.1038/s41550-024-02305-9
Source: www.sci.news
