Juno finds a new auroral feature on Jupiter | EarthSky.org

Bright light blue swirls crowning a blue planet.

NASA stated: “On this Hubble telescope image, a curtain of glowing fuel is wrapped round Jupiter’s north pole like a lasso. This curtain of sunshine, known as an aurora, is produced when high-energy electrons race alongside the planet’s magnetic discipline and into the higher ambiance the place they excite atmospheric gases, inflicting them to glow. The aurora resembles the identical phenomenon that crowns Earth’s polar areas.” Picture through NASA/ ESA/ John Clarke (College of Michigan)/ SwRI.

Scientists from the Southwest Analysis Institute (SwRI) primarily based in San Antonio, Texas, said on March 29, 2021, that they’ve efficiently used the Juno spacecraft to find never-before-seen options related to Jupiter’s aurora. They known as them:

… faint ring-like aurora options … increasing quickly over time.

The increasing rings are about 1,200 miles (2,000 km) throughout, and so they race outward at speeds of roughly three miles (5 km) a second.

Red and white dots on black moving upper left to lower right.

Ultraviolet photographs, proven right here in false shade, captured the quickly increasing auroral rings on Jupiter. Picture through NASA/ JPL-Caltech/ SwRI/ V. Hue/ G. R. Gladstone.

These rings, brilliant in ultraviolet light, seem to have a unique from different auroral options on Jupiter, that are generated by inner processes, that’s, through the movement of charged particles inside Jupiter’s large magnetosphere. These scientists’ statement defined:

Each Jupiter and Earth have magnetic fields that safety from the photo voltaic wind. The stronger the magnetic discipline, the bigger the magnetosphere. Jupiter’s magnetic discipline is 20,000 instances stronger than Earth’s and creates a magnetosphere so giant it begins to deflect the photo voltaic wind 2-Four million miles earlier than it Jupiter.

An instrument on Juno known as the Ultraviolet Spectrograph captured the newly found auroral options, which, in contrast to the remainder of Jupiter’s aurora, are thought to originate close to the sting of the planet’s magnetosphere, the place the magnetosphere brushes up in opposition to the solar wind, a stream of charged particles from the solar. Vincent Hue of SwRI led the research, which was published on March 9, 2021, within the peer-reviewed Journal of Geophysical Analysis. Hue stated:

We these newly found faint ultraviolet options originate hundreds of thousands of miles away from Jupiter, close to the Jovian magnetosphere’s boundary with the photo voltaic wind. The photo voltaic wind is a supersonic stream of charged particles emitted by the solar. Once they attain Jupiter, they work together with its magnetosphere in a approach that’s nonetheless not nicely understood.

Jupiter with blue auroral ring and inset closeups of it.

Juno’s Ultraviolet Spectrograph took photographs of faint aurora options probably triggered by charged particles coming from the sting of Jupiter’s large magnetosphere. The false-color sequence of photographs are 30 seconds aside (pink panels) and show ring-like emissions that develop quickly over time. Picture through NASA/ JPL-Caltech/ SwRI.

How may these new auroral options – these quickly increasing rings of – be generated? These scientists stated that:

… within the outer a part of the Jovian magnetosphere, close to its boundary with the photo voltaic wind, plasma from the photo voltaic wind typically interacts with the Jovian plasma in a approach that’s thought to kind what are known as Kelvin-Helmholtz instabilities. These phenomena happen when there are shear velocities, resembling on the interface between two fluids shifting at totally different speeds.

One other potential sun-related mechanism to create these emission rings is an occasion in Jupiter’s magnetosphere known as magnetic reconnection. You might have heard of magnetic reconnection occurring on the solar, when magnetic discipline strains twist or cross, making new hyperlinks, whereas the disconnected plasma is then freed and may shoot outward in a big or ejection that will finally work together with Earth and trigger auroras. Simply as with Earth, because the photo voltaic wind reaches Jupiter, the Jovian magnetic discipline can then join with the photo voltaic wind, rearranging and reconnecting to set off auroras. This sort of occasion known as a dayside magnetic reconnection.

Each processes – the potential Kelvin-Helmholtz instabilities and the potential dayside magnetic reconnection occasions – are thought to have the ability to generate particle beams that would journey alongside the Jovian magnetic discipline strains, to finally precipitate and set off the ring auroras on Jupiter.

Hue commented:

Though this research doesn’t conclude what processes produce these options, the Juno prolonged mission will permit us to seize and research extra of those faint transient occasions.

Line of clouds looking like side view of row of ocean breakers.

View at EarthSky Neighborhood Pictures. | Kelvin-Helmholtz instabilities might be seen on Earth in Kelvin-Helmholtz clouds, which seem like a row of massive curling waves on the ocean. Berger in Sandpoint, Idaho, captured this photograph of Kelvin-Helmholtz clouds on December 27, 2020. She wrote: “We had been driving dwelling one night in December, 2 days after Christmas, and noticed this lovely picture within the sky east of our approach dwelling.” Thanks, Michelle!

Neon blue ring seen from above around Jupiter's pole.

This illustration exhibits the auroral oval on Jupiter in ultraviolet wavelengths. Picture through NASA/ JPL-Caltech/ SwRI.

Backside line: NASA’s Juno spacecraft, in orbit round Jupiter, took ultraviolet photographs of the large planet and found a quickly increasing auroral ring on the very fringes of the Jovian magnetosphere.

Source: Detection and Characterization of Circular Expanding UV-Emissions Observed in Jupiter’s Polar Auroral Regions

Via SwRI

Kelly Kizer Whitt

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