Scientists solve the 40-year mystery of Jupiter’s X-ray aurora

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Overlayed images of Jupiter’s pole from NASA’s Juno satellite and NASA’s Chandra X-ray telescope. The left shows a projection of the aurora borealis (magenta) X-ray of Jupiter on the JunoCam visible image of the North Pole. The right shows the southern counterpart. Credit: NASA Chandra / Juno Walk / Dunn

A research team led by the University of California, Los Angeles, has solved a decades-old mystery about how Jupiter produces an astonishing burst of X-rays every few minutes.

X-rays are part of Jupiter’s auroras – bursts of visible and invisible light that occur when charged particles interact with the planet’s atmosphere. A similar phenomenon occurs on Earth, where it creates the Northern Lights, but Jupiter is much more powerful, releasing hundreds of gigawatts of energy, enough to briefly power human civilization.

In a new study published in Science Advances, researchers combined close-up observations of Jupiter’s environment by NASA’s Juno satellite, which is currently orbiting the planet, with simultaneous X-ray measurements from the European Space Agency’s XMM-Newton Observatory (in Earth orbit) .

The research team, led by UCL and the Chinese Academy of Sciences, discovered that the X-ray flares were caused by periodic vibrations of Jupiter’s magnetic field lines. These vibrations create waves of plasma (ionized gas) that send heavy ion particles “surfing” along magnetic field lines until they collide with the planet’s atmosphere, releasing energy in the form of X-rays.

Co-lead author Dr. William Dunn (UCL Mullard Space Science Laboratory) said: “We’ve seen Jupiter produce X-ray auroras for four decades, but we didn’t know how it happened. We only knew it was produced when ions crashed into the planet’s atmosphere.”

“We now know that these ions are transported by plasma waves – an explanation that has not been proposed before, although a similar process produces Earth’s aurora borealis. Thus, they could be a global phenomenon, present across many different environments in space.”

For the first time, astronomers have seen the way in which Jupiter’s magnetic field is compressed, which heats up particles and directs them along magnetic field lines down into Jupiter’s atmosphere, creating X-ray auroras. The communication was made by combining in-situ data from NASA’s Juno mission with X-ray observations from ESA’s XMM-Newton instrument. Credit: ESA/NASA/Yao/Dunn

X-ray auroras occur at Jupiter’s north and south poles, often with a regular clock movement – during this observation Jupiter was producing bursts of X-rays every 27 minutes.

Particles of charged ions that strike the atmosphere originate from volcanic gas flowing into space from giant volcanoes on Jupiter’s moon, Io.

This gas is ionized (its atoms are stripped of electrons) due to collisions in Jupiter’s immediate environment, forming a donut of plasma that surrounds the planet.

Co-lead author Dr. Zhonghua Yao (Chinese Academy of Sciences, Beijing) said: “Now that we have identified this fundamental process, there is a wealth of possibilities for where it can be studied next. Similar processes are likely to occur around Saturn, Uranus, Neptune and possibly the exoplanets as well, With different types of charged particles “surfing” the waves.

Co-author Professor Graziella Brandoardi-Raymont (UCLA Space Science Laboratory), said: “X-rays are usually produced by very powerful and violent phenomena such as black holes and neutron stars, so it seems strange that just planets produce them as well.

“We can never visit black holes, because they are beyond space travel, but Jupiter is on our doorstep. With the Juno satellite reaching Jupiter’s orbit, astronomers now have a fantastic opportunity to study an environment that produces X-rays up close.”

Jupiter’s mysterious X-ray aurora borealis explained, ending 40 years of searching for an answer. For the first time, astronomers have seen the way in which Jupiter’s magnetic field is compressed, which heats up particles and directs them along magnetic field lines down into Jupiter’s atmosphere, creating X-ray auroras. The communication was made by combining in-situ data from NASA’s Juno mission with X-ray observations from ESA’s XMM-Newton instrument. Credit: ESA/NASA/Yao/Dunn

For the new study, the researchers analyzed observations of Jupiter and its surrounding environment continuously over a 26-hour period by the Juno and XMM-Newton satellites.

They found a clear correlation between the waves in the plasma detected by Juno and the auroral X-ray flares of Jupiter’s north pole recorded by X-MM Newton. Then they used computer modeling to confirm that the waves would push the heavy particles into Jupiter’s atmosphere.

Why magnetic field lines vibrate periodically is not clear, but the vibration may result from interactions with the solar wind or from high-speed plasma flows within Jupiter’s magnetosphere.

Jupiter’s magnetic field is very strong – about 20,000 times stronger than that of Earth – and therefore Jupiter’s magnetosphere, the area controlled by this magnetic field, is very large. If it were visible in the night sky, it would cover an area several times the size of our Moon.

Scientists discover new auroral feature on Jupiter More information: Z. Yao el al. “Detection of the source of Jupiter’s auroral X-ray flares,” Science Advances (2021). advances.sciencemag.org/lookup… 1126 / sciadv.abf0851 Submitted by University College London

Quote: Scientists have solved a 40-year mystery about Jupiter’s X-ray aurora (2021, July 9), retrieved July 10, 2021 from https://phys.org/news/2021-07-scientists-year-mystery-jupiter -x-ray .programming language

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