Researchers find Jupiter holds 1.5x more oxygen than the Sun

Thick, swirling clouds cover Jupiter from pole to pole. They hold water like Earth’s clouds, but at far greater density. For decades, those clouds have blocked a clear view of what lies beneath. Now, researchers from the University of Chicago and NASA’s Jet Propulsion Laboratory say they have built the most complete picture yet of Jupiter’s deep atmosphere.

The new study, published in The Planetary Science Journal, combines advanced chemistry with realistic atmospheric motion. The work helps settle a long-running debate about how much oxygen Jupiter contains and offers new clues about how the solar system formed.

“This is a long-standing debate in planetary studies,” said Jeehyun Yang, a postdoctoral researcher at the University of Chicago and the study’s first author. “It’s a testament to how the latest generation of computational models can transform our understanding of other planets.”

Astronomers have watched Jupiter’s storms for more than 360 years. Early telescope users recorded what is now known as the Great Red Spot, a vast storm twice Earth’s size that still rages today. Fierce winds and deep cloud layers cover the entire planet in shifting patterns.

What happens below those clouds remains difficult to measure. In 2003, NASA’s Galileo probe plunged into Jupiter’s atmosphere and lost contact as conditions became too extreme. NASA’s Juno spacecraft now studies the planet from orbit, measuring gases in the upper atmosphere such as ammonia, methane, water vapor, and carbon monoxide.

Those measurements offer hints but not a full answer. Oxygen, a key element, is mostly locked in water. Under Jupiter’s conditions, water condenses into clouds, making it uneven and hard to track directly.

Every planet formed from the same basic material as the Sun. Differences in element amounts act like fingerprints of how and where planets grew. For Jupiter, oxygen plays a central role. Much of it is tied up in water, which freezes far from the Sun but stays vapor closer in. Ice gathers more easily than vapor, so oxygen levels can hint at where Jupiter formed before settling into its current orbit.

Past studies disagreed sharply. Some suggested Jupiter holds far less oxygen than the Sun. Others, including recent findings from Juno, pointed to higher values.

Yang and her colleagues saw a way forward by modeling carbon monoxide instead. Carbon monoxide is stable deep in Jupiter’s atmosphere and easier to detect. By tracking how it forms and moves, scientists can infer how much oxygen must exist below the clouds.

Earlier models often simplified Jupiter’s atmosphere into a single vertical column. They relied on hand-built chemical networks and assumed mixing rates. Those choices left large uncertainties.

The new study takes a different approach. The team built an automated chemical network that includes nearly 2,000 reactions among 89 chemical species. They paired this with a two-dimensional hydrodynamic model that simulates how gases move, rise, and sink near Jupiter’s water cloud layer.

“You need both,” Yang said. “Chemistry is important but doesn’t include water droplets or cloud behavior. Hydrodynamics alone simplifies chemistry too much. So, it’s important to bring them together.”

"A key focus involved the so-called Hidaka reaction, which breaks methanol into smaller molecules. For years, scientists argued over whether to include it and how fast it proceeds. Some older models used incorrect rates, which skewed results," Yang told The Brighter Side of News.

"By revisiting laboratory data and modern calculations, our team clarified the reaction’s role. In older models, changing this single reaction could alter results by tenfold. In the new network, its impact was far smaller. That stability comes from capturing many competing chemical pathways at once," he continued.

When the researchers ran traditional one-dimensional models using the improved chemistry, they found that standard mixing assumptions favored low oxygen levels. That clashed with Juno’s observations unless mixing was far weaker than usually assumed.

The two-dimensional simulations told a different story. By allowing atmospheric motion to emerge naturally, these models consistently matched observations when Jupiter’s oxygen level ranged from about one to one and a half times that of the Sun.

The simulations also suggested that Jupiter’s atmosphere mixes more slowly than long believed. A single molecule might take weeks, not hours, to move through certain layers.

“Our model suggests the diffusion would have to be 35 to 40 times slower compared to what the standard assumption has been,” Yang said.

An oxygen level slightly above solar, paired with Jupiter’s known carbon enrichment, implies a high carbon-to-oxygen ratio. That points to a birthplace rich in carbon-bearing material but relatively poor in water ice.

Such a mix suggests strong chemical variation in the early solar system. Jupiter may have grown by collecting carbon-rich solids that drifted through the disk of gas and dust around the young Sun.

“It really shows how much we still have to learn about planets, even in our own solar system,” Yang said.

The findings reshape how scientists model giant planets. By tying chemistry and atmospheric motion together, the study offers a more reliable way to interpret spacecraft data. This approach can be applied to Uranus, Neptune, and gas-rich exoplanets, where direct measurements are even harder.

For humanity, the work sharpens the search for habitable worlds. Knowing how giant planets form and move helps explain how smaller, rocky planets like Earth end up in stable, life-friendly orbits. The methods developed here also improve predictions about planet composition beyond our solar system, guiding future telescope missions.

Research findings are available online in The Planetary Science Journal.

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