Water may be variably distributed across Jupiter's atmosphere: NASA

Water makes up about 0.25 per cent of molecules in Jupiter's atmosphere along its equator -- almost three times that of Sun, according to a study based on data from NASA's Juno mission launched in 2011. 

study, published in journal Nature Astronomy on Tuesday, provided first findings on gas giant's abundance of water since space agency's 1995 Galileo mission. 

According to researchers, including those from NASA's Jet Propulsion Laboratory in US, Jupiter may be extremely dry compared to Sun -- a comparison based not on liquid water, but on presence of its components, oxygen and hydrogen. y said Jupiter was likely first planet to form, and it contains most of gas and dust that wasn't incorporated into Sun.

leing ories about its formation rest on amount of water planet soaked up, NASA scientists explained in a statement.

Water abundance also has important implications for gas giant's meteorology and internal structure, y said. 

"Just when we think we have things figured out, Jupiter reminds us how much we still have to learn," said Scott Bolton, Juno principal investigator at Southwest Research Institute in US. 

"Juno's surprise discovery that atmosphere was not well mixed even well below cloud tops is a puzzle that we are still trying to figure out. No one would have guessed that water might be so variable across planet," Bolton said.

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Juno's Microwave Riometer (MWR) observes Jupiter from above using six antennas that measure atmospheric temperature at multiple depths simultaneously, NASA noted in a statement. 

researchers said MWR takes vantage of fact that water absorbs certain wavelengths of microwave riation, same trick used by microwave ovens to quickly heat food. 

According to scientists, measured temperatures are used to constrain amount of water and ammonia in deep atmosphere, as both molecules absorb microwave riation.

y initially concentrated on equatorial region because atmosphere re appeared to be more well-mixed, even at depth, than in or regions. 

From its orbital perch, riometer was able to collect data from a far greater depth into Jupiter's atmosphere than Galileo probe -- 150 kilometres, where pressure reaches about 480 psi, researchers said.

"We found water in equator to be greater than what Galileo probe measured," said Cheng Li, a Juno scientist at University of California, Berkeley.

"Because equatorial region is very unique at Jupiter, we need to compare se results with how much water is in or regions," Li said.

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