An international team of astronomers has captured new images of auroras above the gas giant Uranus.
This is a composite image of the giant planet Uranus by NASA’s Voyager 2 spacecraft and two different observations made by the NASA/ESA Hubble Space Telescope (one for Uranus’ ring system and one for the planet’s auroras). Image credit: NASA / ESA / Hubble / L. Lamy.
Auroras are produced when high-energy particles from the Sun cascade along magnetic field lines into a planet’s upper atmosphere.
This causes the planet’s atmospheric gasses to fluoresce.
The extra-terrestrial auroras on Jupiter and Saturn are well-studied, but not much is known about the auroras of Uranus.
In 2011, Hubble became the first Earth-based telescope to snap an image of the auroras on Uranus.
In 2012 and 2014 a team of astronomers took a second look at the auroras using the UV capabilities of Hubble’s Space Telescope Imaging Spectrograph.
The team, led by Dr. Laurent Lamy from the Observatory of Paris in Meudon, France, tracked the interplanetary shocks caused by two powerful bursts of solar wind traveling from the Sun to Uranus, then used Hubble to capture their effect on Uranus’ auroras — and found themselves observing the most intense auroras ever seen on the planet.
By watching the auroras over time, the astronomers collected the first direct evidence that these powerful shimmering regions rotate with the planet.
They also re-discovered Uranus’ long-lost magnetic poles, which were lost shortly after their discovery by NASA’s Voyager 2 spacecraft in 1986 due to uncertainties in measurements and the featureless planet surface.
The team’s findings were published online in the Journal of Geophysical Research: Space Physics on March 9, 2017 (arXiv.org preprint).
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L. Lamy et al. Uranus’ aurorae past equinox. Journal of Geophysical Research: Space Physics, published online March 9, 2017; doi: 10.1002/2017JA023918
