The model shows that Jupiter is richer in oxygen than the Sun.
This discovery will help scientists clarify the picture of the formation of all planets in the solar system.
“This is a long-standing debate in planetary science. It shows how modern computational models can change our understanding of other planets,” said study first author Yang Jihyun of the University of Chicago.
Clouds and chemistry
Jupiter's stormy skies have been known for at least 360 years. At that time, astronomers, looking through the first telescopes, discovered the Great Red Spot – a giant storm twice the size of Earth that had been raging for centuries. This is one of many places on the planet: fierce winds and dense cloud cover mean the entire surface of the gas giant is covered in a kaleidoscope of storms.
But exactly what lurks under these storms is still unknown for certain. The clouds are so dense that the Galileo spacecraft lost contact with Earth while diving deep into the atmosphere in 2003. The current mission, Juno, is studying the planet from a safe distance.
Measurements from orbit help determine the composition of the upper layers of the atmosphere: ammonia, methane, ammonium hydrogensulfide, water, carbon monoxide and other substances. Scientists combined this data with knowledge of chemical reactions to build a model of Jupiter's deep atmosphere.
However, the scientific community remains divided on some issues, such as how much water – and therefore oxygen – the planet contains. Yang saw an opportunity to apply a new generation of chemical models to this complex problem.
The chemistry of Jupiter's atmosphere is extremely complex. Molecules move between the extremely hot conditions deep in the atmosphere and the cooler upper layers, changing their state of aggregation and transforming into other substances in thousands of different reactions. It is also necessary to take into account the behavior of clouds and liquid droplets.
To better describe all these phenomena, scientists for the first time combined chemical and hydrodynamic processes in one model, the results of which have been shared in the pages of the Journal of Planetary Science.
“You need both. Chemistry is important, but it doesn't take into account water droplets or the behavior of clouds. Hydrodynamics simplifies chemistry too much. So combining them together is key,” Yang explains.
Elemental composition
One of the research results is a new estimate of the oxygen content on Jupiter. According to calculations, this planet can contain about 1.5 times more oxygen than the Sun.
Scientists have debated this meaning for decades. A recent major study came up with a much lower estimate – as little as 1/3 of solar power. Knowing this quantity is especially important for understanding how our Solar System formed.
All celestial bodies (and ourselves) are composed of the same elements. But at different scales – and these differences can serve as clues to reconstructing the picture of planet formation.
For example, did Jupiter form in its current position or did it originate closer or farther from the Sun and move over time? A clue may be that most of the planet's oxygen is held in water, which freezes and behaves differently if it is too far from the sun's heat. Planets are more likely to accumulate ice than water vapour.
In turn, a better understanding of the conditions that form different types of planets will help us search for habitable worlds beyond the solar system.
The model also shows that circulation in Jupiter's atmosphere is likely to move up and down much more slowly than long thought.
“Our model indicates that turbulent diffusion would be 35–40 times weaker than standard assumptions,” said the planetary scientist.
That is, molecules pass through an atmospheric layer over weeks rather than hours.
“This clearly shows we still have a lot to learn about the planets, even in our own solar system,” Yang concluded.
