
Lava erupting on Jupiter鈥檚 volcanic moon, Io, is over 1000掳C, according to a new estimate made using radio telescopes.
at the University of California, Berkeley, and her colleagues analysed observations of Io鈥檚 atmosphere made using the Atacama Large Millimetre/Submillimetre Array (ALMA) 鈥 a collection of radio telescopes operated by the European Southern Observatory within Chile鈥檚 Atacama desert.
The study focused on sodium chloride and potassium chloride gases that are thought to be belching from lava lakes and magma chambers on the Jovian moon. By comparing the amounts of the two gases, the team were able to estimate how hot the sources of the gases are.
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鈥淭he ratio of [sodium chloride to potassium chloride] gas abundance in Io鈥檚 atmosphere will change depending on the thermochemical conditions of the magma chambers from which they are outgassed, so by observing their abundance ratios we can indirectly infer the temperature,鈥 says Redwing.
The researchers found that the magma on Io is probably about 1300 kelvin, or just over 1000掳C (1900掳F) 鈥 similar to the temperature of lava from volcanoes on Earth. However, the resolution of the ALMA observations wasn鈥檛 sufficient to allow the team to pin down the precise locations of the features where those temperatures arise.
鈥淭his study confirms that the lavas erupting on Io are likely mostly basaltic in composition, based on their temperature,鈥 says at Brigham Young University in Utah. This would make them similar to the molten rock that has emerged on the floor of Earth鈥檚 oceans as well as the moon, Venus and Mars, she says, adding that further examination of the sodium chloride and potassium chloride gases could reveal more about the depth of magma chambers and how that might vary across Io.
The magma temperature estimated in the new ALMA study is also consistent with results from the Galileo mission in the late 1990s and early 2000s, but better data will be needed to fully understand Io鈥檚 enigmatic volcanism.
That could come from a dedicated mission that flies past or orbits the moon. Such a spacecraft could gather higher resolution data of the distribution of volcanic gases as well as make direct measurements of the lava temperature, says Radebaugh.
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