James Webb Telescope Discovers Mysterious Changes in Asteroid’s Rings

The James Webb Space Telescope has detected surprising changes in the two narrow rings surrounding Chariklo, a small body orbiting between Saturn and Uranus — challenging scientists’ understanding of how ring systems evolve.

Chariklo is only about 250 kilometers across, yet it possesses something normally associated with much larger worlds: a system of two dense rings.

Astronomers discovered those rings in 2013.

Now, new observations from the James Webb Space Telescope (JWST) show that the rings may not be as stable as scientists once thought.

The inner ring has become significantly more opaque, while the outer ring produced a much weaker signal than earlier observations.

The findings were published in the peer-reviewed journal Science Advances on September 9, 2026.

A Tiny World With Its Own Rings

Chariklo is classified as a Centaur, a group of small Solar System bodies whose orbits lie between those of the giant planets.

It travels around the Sun between Saturn and Uranus, at roughly 17 times the Earth-Sun distance.

Despite its relatively small size, Chariklo has two prominent rings.

That alone makes it an unusual object.

Before Chariklo’s rings were discovered, ring systems were primarily associated with the giant planets of the Solar System, including Jupiter, Saturn, Uranus and Neptune.

The discovery showed that even relatively small bodies can maintain ring systems.

James Webb Saw Something Unexpected

The latest discovery came from an observation made with the James Webb Space Telescope on October 18, 2022.

Astronomers used a technique called a stellar occultation.

During an occultation, an object passes in front of a distant star.

As the object and its rings block portions of the star’s light, astronomers can measure tiny changes in brightness.

Those changes provide information about the size, structure and opacity of the rings.

The JWST observation provided an unusually detailed look at Chariklo’s ring system.

The Two Rings Changed in Opposite Directions

This is the part that surprised researchers.

Chariklo’s two rings did not appear to change in the same way.

The inner ring, known as C1R, appeared significantly more opaque than it had during earlier observations.

The outer ring, known as C2R, produced a much weaker signal.

In simple terms, the inner ring appears to have become harder to see through, while the outer ring appears to have become more transparent.

Researchers say the difference could indicate that the rings are actually changing over time.

Why Is This Surprising?

Ring systems are not necessarily permanent structures.

They consist of particles that can collide, spread, interact with the central body and respond to gravitational forces.

However, scientists previously had limited evidence showing that Chariklo’s rings could undergo significant structural changes over relatively short timescales.

The new observations suggest that the system may be evolving on a decadal timescale.

That is extremely interesting because astronomical processes often occur over thousands, millions or even billions of years.

Chariklo appears to be giving astronomers an opportunity to observe ring evolution within a human lifetime.

What Could Be Making the Inner Ring Denser?

Scientists have several possibilities.

One explanation is that material could be moving into the inner ring.

Another possibility is that collisions between larger particles could break them into smaller grains.

A larger number of smaller particles could make the ring appear more opaque.

Chariklo’s gravity and resonance effects may also play an important role in controlling how particles move within the ring system.

Researchers have not yet determined which explanation is responsible.

Why Could the Outer Ring Be Fading?

The outer ring shows the opposite behavior.

Its weaker signal could indicate that material is gradually being lost from the ring.

If particles are escaping or spreading away from the ring, the structure could become increasingly transparent.

Researchers also caution that differences between observations at different wavelengths could contribute to the apparent change.

That means scientists cannot yet say with certainty that all of the observed difference represents physical changes over time.

More observations are needed.

The Rings May Be Controlled by Resonance

One of the most interesting aspects of Chariklo’s system is the influence of gravitational resonances.

Resonance occurs when orbital motions interact in a way that repeatedly influences an object’s movement.

In Chariklo’s case, gravitational interactions involving the central body can affect the structure of the rings.

Researchers say these resonances could help reshape the rings over timescales of decades.

This may explain why the ring system appears capable of changing much faster than previously expected.

Chariklo Is Not an Ordinary Asteroid

Calling Chariklo simply an asteroid can be misleading.

It belongs to a population known as Centaurs, which occupy the outer Solar System between the orbits of the giant planets.

These objects can have complicated orbital histories and can be influenced by the powerful gravity of planets such as Saturn and Uranus.

Chariklo is also the largest known Centaur, with a radius of approximately 125 kilometers.

Its unusual rings make it even more scientifically valuable.

How Did Chariklo Get Its Rings?

Scientists still do not have a complete answer.

Several possibilities have been proposed for the origin of the material.

The rings could have formed from collisions involving Chariklo or from material released from the body.

Gravitational interactions could then have confined that material into narrow ring structures.

But the exact formation mechanism remains uncertain.

The newly observed changes may provide additional clues.

Understanding how the rings evolve could help researchers work backward and determine how they formed in the first place.

Why Scientists Care About Such a Small Object

Chariklo may be tiny compared with planets, but it provides a natural laboratory for studying ring physics.

Saturn’s rings are enormous and extremely complex.

Chariklo’s rings are much smaller.

That makes it possible to study a different regime of ring dynamics.

If scientists can understand why Chariklo’s rings change, they may gain insight into how ring systems form and disappear throughout the Solar System.

The discovery could therefore have implications well beyond Chariklo itself.

Could Chariklo’s Rings Eventually Disappear?

Possibly.

The current observations do not establish the future lifetime of the rings.

But if the outer ring is losing material, it could eventually become significantly less dense or even disappear.

At the same time, material could continue to replenish or restructure the inner ring.

That means the system may not have a simple “stable or unstable” future.

Instead, it could continually evolve as particles move between different regions.

Scientists need additional observations to determine whether the changes continue.

James Webb Is Giving Astronomers a New Tool

The discovery also demonstrates an unusual capability of the James Webb Space Telescope.

JWST is best known for studying distant galaxies, exoplanets, stars and nebulae.

But it can also investigate objects much closer to home.

The Chariklo observation shows that JWST can use stellar occultations to examine tiny structures around Solar System bodies.

This gives astronomers another way to study objects that are too small and distant to resolve directly as ordinary images.

Why Can’t We Simply Photograph the Rings?

Chariklo is extremely far away and very small compared with planets such as Saturn.

Even powerful telescopes cannot simply produce a detailed image of its rings in the same way that spacecraft can photograph planetary rings.

Instead, astronomers can study how Chariklo and its rings affect the light of background stars.

By measuring the timing and strength of those changes, researchers can reconstruct information about the ring system.

It is a little like learning the shape of an object from its shadow.

The Discovery Raises a Bigger Question

If Chariklo’s rings can change significantly within decades, how many other small ring systems might also be evolving?

Astronomers have discovered ring systems around several small bodies in the outer Solar System.

But observations are limited.

Many of these systems may have changed since they were first discovered.

Future stellar occultations could reveal whether Chariklo is unusual or whether rapidly evolving rings are actually common among small Solar System bodies.

What Happens Next?

Researchers want additional observations of Chariklo.

Future stellar occultations, especially observations made at visible wavelengths, could help determine whether the changes continue.

They could also help distinguish between two possibilities:

1. The rings are genuinely evolving over time.
2. Some of the differences are caused by wavelength-dependent behavior.

If future observations confirm continued changes, scientists will have much stronger evidence that Chariklo’s rings are dynamically evolving.

Key Facts

• Object: Chariklo
• Type: Centaur / small outer-Solar-System body
• Location: Between Saturn and Uranus
• Distance: About 17 times the Earth-Sun distance
• Size: Approximately 250 km across
• Rings: Two dense rings
• Ring discovery: 2013
• Telescope: James Webb Space Telescope
• JWST observation: October 18, 2022
• Inner ring: Became more opaque
• Outer ring: Produced a weaker signal
• Research journal: Science Advances
• Publication: September 9, 2026
• Main mystery: What is causing the rings to change?

Frequently Asked Questions

What is Chariklo?

Chariklo is a small Solar System body known as a Centaur. It orbits the Sun between Saturn and Uranus and is surrounded by two narrow rings.

Does Chariklo have rings like Saturn?

Yes, but they are vastly smaller. Chariklo has two narrow dense rings, while Saturn has an enormous and much more complex ring system.

Did James Webb discover Chariklo’s rings?

No. Astronomers discovered Chariklo’s rings in 2013. The James Webb Space Telescope later observed the system and revealed unexpected changes in the rings.

What changed in Chariklo’s rings?

The inner ring became significantly more opaque, while the outer ring produced a much weaker occultation signal than previously observed.

Why are Chariklo’s rings changing?

Scientists do not yet know. Possible explanations include material being added to or removed from the rings, particle collisions, dynamical restructuring and wavelength-dependent effects.

How far away is Chariklo?

Chariklo orbits at nearly 17 times the average Earth-Sun distance, roughly two billion kilometers from Earth when described in the research context.

Could Chariklo’s rings disappear?

It is possible that parts of the ring system could lose material over time, but scientists do not yet know its long-term fate.

The Bigger Picture

For decades, planetary rings were largely associated with giant worlds such as Saturn.

Chariklo changed that picture when astronomers discovered its two narrow rings in 2013.

Now, the James Webb Space Telescope has added another surprise.

The rings do not appear to be completely static.

One has become more opaque, while the other has become less prominent.

Whether this represents genuine physical evolution, wavelength-dependent behavior or a combination of both remains an open question.

That uncertainty is exactly what makes the discovery scientifically valuable.

Astronomers now have an opportunity to watch a distant ring system evolve and test ideas about how these structures form, interact and eventually disappear.

A tiny world between Saturn and Uranus may therefore be offering scientists a new laboratory for understanding one of the most recognizable structures in our Solar System.

Sources

Primary research: Science Advances, “JWST stellar occultation reveals unexpected changes in Chariklo’s ring system,” published September 9, 2026.

Research institution: Observatoire de Paris — PSL, “The ‘pocket rings’ of the small body Chariklo are evolving.”

Research release: IAA-CSIC / EurekAlert, “James Webb Space Telescope discovers that Chariklo’s invisible rings are changing.”

Editorial note: The cause of the observed changes has not been definitively established. The article therefore distinguishes confirmed observations from proposed explanations.