A team of researchers co-led by Scientists from University College London (UCL) has solved a decades-old mystery about how Jupiter produces spectacular X-ray bursts every few minutes. X-rays are part of Jupiter's auroras — bursts of visible and invisible light that occur when charged particles interact with Jupiter's atmosphere. A similar phenomenon occurs on Earth, forming the Northern Lights, but Jupiter's Northern Lights are much more powerful, releasing tens of billions of watts of energy, enough to provide a temporary impetus for the entire human civilization.
In a new study published in Science Advances, the researchers combined close-up observations of Jupiter's environment by NASA's Juno probe with synchronized X-ray measurements from the European Space Agency's XMM-Newton Observatory, located in Earth's orbit.
A team led by UCL and the Chinese Academy of Sciences found that X-ray flares are triggered by periodic vibrations of Jupiter's magnetic field lines. These vibrations create plasma (ionized gas) waves that cause heavy ionic particles to "surf" along magnetic field lines until they smash into the planet's atmosphere, releasing energy in the form of X-rays.
Co-lead author Dr William Dunn from UCL's Mallard Space Science Laboratory said: "We've been observing Jupiter producing X-ray auroras for forty years, but we don't know how that happens. All we know is that they are created when ions crash into a planet's atmosphere. ”
"Now we know that these ions are transported by plasma waves — an explanation that no one has proposed before, although a similar process produces auroras on Earth." As such, it may be a universal phenomenon that exists in many different environments of space. ”
X-ray auroras occur at Jupiter's north and south poles and are often regular —during this observation, Jupiter produces a burst of X-rays every 27 minutes.
The charged ionic particles that hit the atmosphere come from volcanic gases poured into space from huge volcanoes on Jupiter's moon Europa. This gas becomes ionized due to a collision in Jupiter's immediate environment, forming a "donut" of plasma orbiting the planet.
Co-first author Dr. Zhonghua Yao said: "Now that we have identified this basic process, there are many possibilities where it can be studied next. A similar process can occur around Saturn, Uranus, Neptune, and possibly exoplanets, with different kinds of charged particles 'surfing in waves'. ”
Co-author Professor Grazilla Branduardi-Raymont said: "X-rays are usually produced by phenomena that are extremely powerful and violent, such as black holes and neutron stars, so it seems strange that mere planets also produce X-rays. ”
"We'll never be able to access black holes because they're beyond the reach of space travel, but Jupiter is right on our doorstep." With juno's moons in orbit around Jupiter, astronomers now have a perfect opportunity to study up close the environment that produces X-rays. ”
In the new study, the researchers analyzed continuous observations of Jupiter and its surroundings over a 26-hour period by Juno and the XMM-Newton moon.
They found a clear correlation between the plasma waves detected by Juno and the X-ray aurora flares recorded by Jupiter's North Pole recorded by the XMM-Newton satellite. They then used computer modeling to confirm that the waves would push heavy particles into Jupiter's atmosphere. Why magnetic field lines vibrate periodically is unclear, but this vibration may be due to interactions with the solar wind or high-velocity plasma streams within Jupiter's magnetosphere.
Jupiter's magnetic field is very strong — about 20,000 times that of Earth ' magnetic field — so its magnetosphere, the region 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.
The work was supported by the Chinese Academy of Sciences, the National Natural Science Foundation of China, the Uk Science and Technology Facilities Council (STFC), the Royal Society, the Natural Environment Research Council, as well as ESA and NASA.