Auroras are caused by charged particles hitting a planet’s atmosphere at high speed, visible as the Northern Lights or Aurora Australis on Earth.  

Jupiter also has auroras but these are invisible to the eye because they lie in the UV and X-ray portions of the spectrum.

Now, by using data from three different satellites measuring Jupiter’s space environment, a team led by the Japan Aerospace Exploration Agency (JAXA) including a researcher from Lancaster University found out what causes this aurora.

They discovered that the acceleration necessary for the X-ray aurora is triggered by the solar wind which is a stream of highly charged particles from the Sun.

Detailed analysis of the X-ray emissions also show that they peak in regions closest to the outer edges of the planet’s protective magnetic bubble (magnetosphere), where the interaction with the solar wind would be strongest.

The results appear in the Journal of Geophysical Research.

Physicist Dr Sarah Badman is a Co-Investigator and helped interpret the data regarding the origin of the X-rays.

She said: "Seeing Jupiter’s aurora in X-rays allows us to probe a different region of its space environment, and at the highest energies.”

Dr Badman was funded by the Royal Astronomical Society for this research. She also has a five year fellowship funded by the Science and Technologies Facilities Council to support a programme of research entitled "Illuminating Solar-Planetary interactions".