Newfound
glowing spots on Jupiter seem unexpectedly to come from electron beams whipping
around the giant planet's volcanic moon Io.
Io
is the most volcanic body in the solar system, with its entire surface likely
made up of lava from the moon's hundreds of volcanoes.
Io
also causes glowing spots
hundreds of miles across on its mother planet that are similar to the aurora
borealis or northern lights in the Northern Hemisphere on Earth.
As
Jupiter spins, its magnetic field sweeps past Io, stripping off roughly 1 ton
(about 1,000 kilograms) of matter off Io every second. This matter becomes
electrically charged plasma in the magnetic field, forming a doughnut-shaped
cloud. As Io orbits the planet, plasma surges around it like rivers do around
boulders, creating waves that blast Jupiter's atmosphere with electrons to
create auroras.
The
glowing spots on Jupiter
are typically located downstream of the flow of charged particles from the
plasma torus. Now a team of planetologists unexpectedly found auroras occurring
upstream of this flow.
"The
results are surprising because no theory predicted upstream spots," said
researcher Bertrand Bonfond of the University of Liege in Belgium.
Bonfond
and colleagues in Belgium and Germany saw these new spots by using the Hubble
Space Telescope to observe Jupiter in ultraviolet wavelengths.
>The
researchers think interactions between Io
and Jupiter cause electrons to curve from one hemisphere of the planet around
the moon to the other hemisphere, creating these unexpected spots, Bonfond told
SPACE.com.
These new findings could shed light on very common occurrences in the universe
— when electrically conductive bodies such as Io orbit near magnetic bodies
such as Jupiter. For example, some recently discovered exoplanets are thought
to be in such configurations with their parent stars.
To
further test their new theory of how these glowing spots form, Bonfond and his
colleagues plan further observations of the auroras later this year, after
scheduled repairs and improvements to Hubble are made.
The scientists detailed their findings online March 15 in the journal Geophysical
Research Letters.
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