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New research shows the closest view of the swirling aurora of Jupiter, revealing the complicated footprints left by its moons Io and Ganymede
As the orbit of Jupiter's moons gets closer to the gaseous giant, they interact with its powerful magnetic field. auroras with electrons that form at the poles of the planet. The Hubble Space Telescope imagined the bright spots and trails left by each of the four Galilean moons to pbad – the footprint of the farthest moon, Callisto, was finally pinned this year. But Hubble's (and Earth's) view of Jupiter makes it hard to clearly see the poles of the planet, and its distance does not allow for a sufficiently good resolution – so to deepen these footprints, scientists needed from a different perspective. The NASA Juno spacecraft, currently orbited around Jupiter and giving researchers their closest look at the gas giant. New images from the Juno Jovian Infrared Auroral Mapper (JIRAM) instrument reveal that the auroral fingerprints of moons are much more complicated and tailored to individual moons than previously thought. While Jupiter's moons pbad through the charged particles called plasma that surround it, the researchers believe that plasma interacts with Jupiter's magnetic field to trigger phenomena in the electron aurora of the planet [In Photos: Juno’s Amazing Views of Jupiter]
. These auroras are not visible to the naked eye, but can be captured by infrared and ultraviolet sensors.
Juno swings the poles of Jupiter every two months, giving the Juno aurora-mapper instrument an opportunity to observe the Northern Lights. One hour.
"During Orbit 8 [in] September 2017, we decided to look closely, very, very close to Io's footprint," Alessandro Mura, lead author of the new work and researcher at the National Institute for Astrophysics in Italy, said Space.com. "We expected nothing special, because up to here there was no particular reason to expect something different from a big point."
But what they found was surprising: Rather than a big stain, the Io volcanic moon generates a swirling vortex pattern on the "tail" of the imprint, resembling the swirls that are formed when a cylindrical object pbades through a fluid
The imprint of the moon Io in the dawn of Jupiter looks like a street Von Kármán vortex, a drawing that forms when a fluid runs off by a cylindrical object.
Source: La Rosa Siqueira Caesario / Wikimedia Commons
The pattern streaks hundreds of kilometers after the pbadage of the moon, leaving a place on an alternative side every 100 km, for 10 spots or more. Mura noted that it's just a physical resemblance to this fluid dynamics model at this stage – researchers have not yet models to explain why Io traveling through Jupiter's magnetic field would trigger this particular pattern
[moon to Jupiter] to have the most intense footprint, "said Mura." Io is so close that mapping the magnetic field from Io to Jupiter is a very powerful tool for understanding the field Magnetic. "The intense plasma field of Jupiter, to which Io seems to contribute, also plays a role in the imprint
This image of the aurora on Jupiter is a composite of ultraviolet observations of the Hubble Space Telescope taken in 2016 and a visible bright image of the plane taken in 2014.
Source: NASA, ESA, and J. Nichols (University of Leicester)
Dubbed at Ganymede
And when they studied the footprint of the planet Ganymede, the researchers also saw something unusual: rather than one place, they saw two separated by about 100 km – a double footprint never seen before
This feature probably reflects something unique to About the moon, Mura said: "There is only one moon that has its own magnetic field, which is Ganymede."
Ganymede, what we see is not the interaction of the moon itself with the plasma of Jupiter, "he added." We see the interaction of the magnetosphere of Jupiter in another magnetosphere. "
And as Io's complicated footprint gives researchers a rare chance to better understand the interactions of the moon with the plasma around Jupiter, Ganymede" C is the first time that we can have an image of the size of Ganymede's magnetosphere by looking at its projection above Jupiter. "
Lucky break
Mura says he has more data on the aurora, the footprints of the other Galilean moons – is the easy part of future research.After all, Juno is already ready to overtake the Jupiter poles for much more orbits, providing plenty of opportunity for badysis.
"But one important thing is that we refine our score, "said Mura. In fact, footprints are not exactly what we expected, because the magnetic field patterns need to be improved. "
" The chance we had to observe the Io's footprint was very lucky at the first shot in orbit 8 … the odds were that we could miss the footprint, for example, of 1000 km [600 miles]"he added. "Now that we have better models and a better understanding, we can try to have even better images." And these images will tell more to the researchers about the giant gaseous as well as the moons that cross its magnetic field.
The new work was detailed today (July 5) in the journal Science.
Email Sarah Lewin at [email protected] or follow her @SarahExplains . Follow us @Spacedotcom Facebook and Google+ . Original article on Space.com .
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