Left: the image of Io taken in the near-infrared with adaptive optics at the Gemini North telescope on August 29, 2013. Image credit: Katherine de Kleer / UC Berkeley / Gemini Observatory / AURA. Right: NASA’s Galileo spacecraft acquired this image of Io in July 1999. Image credit: NASA / JPL / University of Arizona.
Io – the innermost of the four Galilean moons of Jupiter and the fourth-largest moon in our Solar System – is 3,630 km across.
Aside from Earth, it is the only known place in the Solar System with volcanoes erupting hot lava like that on our planet.
Volcanoes were first discovered on Io in 1979, and subsequent studies by NASA’s Galileo spacecraft and ground-based telescopes show that eruptions and lava fountains occur constantly, creating rivers and lakes of lava.
Only 13 giant eruptions were observed between 1978 and 2006, in part because only a handful of astronomers regularly scan the moon.
In August 2013, Dr Katherine de Kleer and Dr Imke de Pater, both of the University of California Berkeley, discovered three unusually large volcanic eruptions on Io.
“These new events are in a relatively rare class of eruptions on Io because of their size and astonishingly high thermal emission. The amount of energy being emitted by these eruptions implies lava fountains gushing out of fissures at a very large volume per second, forming lava flows that quickly spread over the surface of Io,” said team member Dr Ashley Gerard Davies of NASA’s Jet Propulsion Laboratory.
The scientists discovered the first two eruptions on August 15, 2013, in Io’s southern hemisphere, using the near-infrared camera coupled to the adaptive optics system on the Keck II telescope.
The brightest – at a caldera named Rarog Patera – was calculated to have produced a 130-square-km, 10-m-thick lava flow.
The other eruption – near a caldera called Heno Patera – produced flows covering 310 square km.
The third eruption – the largest and most powerful event of the trio – was discovered on August 29. According to the researchers, the energy emitted was about 20 Terawatts and expelled many cubic km of lava.
Source:
http://www.sci-news.com/astronomy/science-three-massive-volcanic-eruptions-io-02091.html