Jupiter’s exact composition remains a mystery, which is precisely why NASA’s Juno spacecraft is there. Now, a group of astronomers have found a new approach to measure the planet's chemical composition. In doing so, they have discovered that the gas giant might be rich in water.
As reported in the Astronomical Journal, researchers used ground-based observations of Jupiter's Great Red Spot to identify chemical signatures of important elements. By studying the deep clouds of the Spot in infrared, they established the presence of water and carbon monoxide. This suggests that Jupiter has between two and nine times more oxygen than the Sun.
The finding of oxygen molecules matches previous models of Jupiter, which suggested abundant water in the gas giant. Juno is currently probing the atmosphere of the planet deeper than any previous study and will verify if these findings are correct.
"The moons that orbit Jupiter are mostly water ice, so the whole neighborhood has plenty of water," team leader Gordon Bjoraker, from NASA’s Goddard Space Flight Center, said in a statement. "Why wouldn't the planet – which is this huge gravity well, where everything falls into it – be water-rich, too?"
Astronomers have found plenty of circumstantial evidence for a large presence of water on Jupiter, but so far they have been stumped trying to find direct confirmation. Researchers believe that the atmosphere of Jupiter has a base layer of water ice and liquid water, a middle layer of ammonia and sulfur, and a top layer of ammonia.
The team will need to test this approach using other parts of Jupiter as well. If Bjoraker's approach is correct, it could even be applied to the other giant planets in the solar system. The priority though remains Jupiter and an assessment of its global water abundance.
"Jupiter's water abundance will tell us a lot about how the giant planet formed, but only if we can figure out how much water there is in the entire planet," said Steven M. Levin, a Juno project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.
The chemical composition of Jupiter is crucial in our understanding of how the giant planet formed, and may even provide clues on the formation of other stellar systems.