31 October 2017
Jupiter’s south pole, as seen by NASA’s Juno spacecraft from an altitude of 32,000 miles (52,000 kilometers)
(Credit: NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles)
Astronomers are puzzled by new research which shows that the bright lights seen on Jupiter’s northern and southern poles both pulse in very different ways.
The study, now published in Nature Astronomy, found the very high-energy X-ray emissions at Jupiter’s south pole consistently pulse every 11 minutes, while those at the north pole are erratic and fluctuate in brightness.
This is different to Earth’s north and south auroras, which broadly mirror each other in activity. Other similarly large planets, such as Saturn, do not produce any detectable X-ray aurora, which makes the findings at Jupiter particularly mystifying.
Lead author Dr William Dunn, who is funded by STFC and represents both the UCL Mullard Space Science Laboratory and the Harvard-Smithsonian Center for Astrophysics, said: “We didn’t expect to see Jupiter’s X-ray hot spots pulsing independently as we thought their activity would be coordinated through the planet’s magnetic field. We need to study this further to develop ideas for how Jupiter produces its X-ray aurora.”
The team will now combine data collected from NASA’s Juno mission, which arrived at Jupiter in 2016, with information from ESA’s XMM-Newton and NASA’s Chandra X-ray observatories to try to work out how the auroras are produced.
Dr Dunn added: “If we can start to connect the X-ray signatures with the physical processes that produce them, then we can use those signatures to understand other bodies across the Universe such as brown dwarfs, exoplanets or maybe even neutron stars. It is a very powerful and important step towards understanding X-rays throughout the Universe.”
One of the theories to be investigated is that Jupiter’s auroras form separately when the planet’s magnetic field interacts with the solar wind. The team suspect the magnetic field lines vibrate, producing waves that carry charged particles towards the poles and these change in speed and direction of travel until they collide with Jupiter’s atmosphere, generating X-ray pulses.
Learn more on the UCL website - Jupiter’s X-ray auroras pulse independently