The Juno Probe Has Identified The Source Of X-ray Flashes At The Poles Of Jupiter
Thanks to the Juno spacecraft, astronomers have found out that the X-ray flashes that occur at the poles of Jupiter during the auroras are formed as a result of the fact that the magnetic field lines of the planet periodically vibrate. The results of the study are available in the scientific journal Science Advances.
"We have known for four decades that during the auroras, Jupiter produces flashes of X-ray radiation, but we did not understand why this happens. We only knew that they were connected with the streams of ions that fell into the atmosphere of the planet. Our study showed that these particles carry plasma waves, similar to how ion auroras appear on Earth," said William Dunn, a researcher at the University of California.
For a long time, astronomers believed that auroras in the atmospheres of the planets of the Solar system arise as a result of interactions between their magnetic field and charged particles of the solar wind. The magnetic field forces charged particles to penetrate the atmosphere of planets in the vicinity of their poles. There they collide with gas atoms, as a result of which a glow is formed, which is called the aurora borealis.
The most powerful phenomena of this kind occur on Jupiter: there they are several orders of magnitude more powerful than on Earth. Observations of orbiting telescopes and the Juno probe recently indicated that these auroras are not associated with solar wind particles, but with the ejections of volcanoes on the surface of Io, one of Jupiter's moons.
Thanks to the following observations of Juno, scientists have discovered another oddity. It was associated with X-ray flashes that constantly occur at the poles of Jupiter during the auroras. As it turned out, they do not appear simultaneously, but alternately – now at one, then at the other pole of the planet. Scientists do not know the exact causes of such asymmetry, nor the mechanisms of the appearance of such outbreaks.
In a new study, Dunn and his colleagues suggested why this is happening. They compared scientific data and images of the XMM-Newton X-ray orbiting telescope and the Juno spacecraft.
Astronomers have discovered that simultaneously with each circumpolar flash of X-ray radiation on Jupiter, the instruments recorded fluctuations in the magnetic field lines of the planet. They twisted the surrounding plasma clusters into a kind of spiral, dispersed the ions present in them, and forced them to descend towards the circumpolar regions of the planet.
There, these particles collided with gas molecules, with the results of which X-ray flashes were formed. Similarly, one of the types of auroras that occurs on Earth, associated with the penetration of charged ions into the upper atmosphere.
Astronomers can not yet say what causes the vibrations of the magnetic field of Jupiter. They admit that they can be connected both with the action of the solar wind on the magnetosphere of the gas giant and with some internal processes in the cloud of charged particles that surround Jupiter.
Dunn and his colleagues hope that further observations of Juno will help to get an answer to this question. That is critically important not only for understanding how X-ray flashes occur on Jupiter but also for searching for possible "clones" of this phenomenon in the atmosphere of Saturn, Uranus, Neptune, and other planets with their magnetic field.