Auroras at Jupiter's poles act independently

Researchers take advantage of rare opportunity to observe polar regions through Juno mission and space telescopes.
By Laurel Kornfeld | Nov 01, 2017
Auroras in Jupiter's north and south polar regions act independently of one another, according to observations conducted by a study team using the European Space Agency's (ESA) X-MM-Newton telescope and NASA's Chandra X-ray Observatory.

Researchers at University College in London and at the Harvard-Smithsonian Center for Astrophysics led a study of high-energy X-ray auroras at both of Jupiter's poles and were surprised to learn that unlike auroras on the poles of other planets, those at Jupiter's poles do not mirror one another but pulse independently.

Activities of Earth's north and south pole auroras mirror one another. Saturn does not appear to experience any X-ray auroras.

X-ray pulses at Jupiter's south pole occur regularly every 11 minutes while those at its north pole are chaotic, with unpredictable increases and decreases in brightness.

"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," explained study lead author William Dunn of both UCL Mullard Space Science Laboratory in the UK and the Harvard-Smithsonian Center for Astrophysics.

"We need to study this further to develop ideas for how Jupiter produces its X-ray aurora, and NASA's Juno mission is really important for this."

The researchers observed Jupiter using both space observatories in May and June of 2016 and in March 2007 to map the planet's X-ray emissions and identify X-ray hot spots at its poles.

NASA's Juno spacecraft, which arrived at Jupiter in 2016, does not have a science instrument capable of detecting X-rays; however, it is collecting other data at the polar regions that scientists hope to combine with the X-MM and Chandra data to better understand the planet's auroras.

Scientists are fortunate that Juno is studying both of Jupiter's poles at the same time, making it possible for them to compare activity at the poles with the giant planet's complex magnetic interactions, emphasized study co-author Graziella Banduardi-Raymont of UCL Space and Climate Physics.

"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," Dunn stated.

One theory the researchers hope to test as they observe Jupiter's polar activity over the next two years is that the northern and southern auroras form separately as a result of interactions between the planet's magnetic field and the solar wind.

A paper discussing the findings has been published in the journal Nature Astronomy.

 

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