For the first time ever, researchers have studied Jupiter's X-ray aurora at the same time that a massive storm from the sun arrived at the planet. These storms create Jupiter's "northern lights" through the generation of a new X-ray aurora, one that is eight times as bright as standard auroras on the planet and possesses hundreds of times more energy than the aurora borealis that we observe here on Earth.
The findings stem from NASA's Juno mission, which took place in the summer, with the goal of understanding the nature of the relationship between the two biggest structures in the solar system: the region controlled by Jupiter's magnetic field and the region controlled by solar wind.
"There's a constant power struggle between the solar wind and Jupiter's magnetosphere," said William Dunn, lead author of the study. "We want to understand this interaction and what effect it has on the planet. By studying how the aurora changes, we can discover more about the region of space controlled by Jupiter's magnetic field, and if or how this is influenced by the Sun. Understanding this relationship is important for the countless magnetic objects across the galaxy, including exoplanets, brown dwarfs and neutron stars."
When storms erupt from the sun, particles are thrown into space in the solar wind, and when these storms are massive enough, the winds increase in strength and lead to the compression of Jupiter's magnetic field. This causes a shift in the boundary of this magnetosphere with the solar wind two million kilometers through space, an interaction that causes the powerful X-rays in Jupiter's impressive northern lights.
The team based their findings on the X-rays monitored during two 11-hour observations that took place in October 2011 during a period when scientists predicted that an interplanetary coronal mass ejection would make its way from the sun to Jupiter. After collecting the data, they using imaging techniques to locate the source of the X-ray activity and pinpoint areas in need of further research.
Eventually, scientists hope to reveal how these X-rays form using data not only from the Juno mission, but also from European Space Agency's X-ray space observatory, XMM-Newton and NASA's Chandra X-ray observatory.
"Comparing new findings from Jupiter with what is already known for Earth will help explain how space weather is driven by the solar wind interacting with Earth's magnetosphere," said Graziella Branduardi-Raymont, supervisor of the study. "New insights into how Jupiter's atmosphere is influenced by the Sun will help us characterize the atmospheres of exoplanets, giving us clues about whether a planet is likely to support life as we know it."
The findings were published in the March 22 issue of the Journal of Geophysical Research: Space Physics.