A new Webb Space Telescope image of the nearby bright star Fomalhaut shows never-before-seen details, including interlocking dust rings that hint at the power of unseen planets. A team of University of Arizona astronomers used NASA’s James Webb Space Telescope to image hot dust around the nearby young star Fomalhaut to study the first asteroid belt ever seen in infrared light outside our solar system. The image shows concentric rings of concentric dust, some of which have never been seen before. These belts were most likely carved by gravitational forces created by buried unseen planets.

To the surprise of astronomers, dust structures are much more complex than our solar system’s asteroids and Kuiper dust belts. There are three interlocking belts extending 14 billion miles or 23 billion kilometers from the star; It is 150 times greater than the Earth’s distance from the Sun. The outermost belt is about twice the size of our solar system’s Kuiper belt, which consists of small bodies and cold dust beyond Neptune, the farthest known planet. The never-before-seen inner belts in the Fomalhaut system were first discovered by Webb. The results were published May 8 in the journal Nature Astronomy .

The belts surround the young, hot star about 25 light-years from Earth and visible to the naked eye as the brightest star in the southern constellation Pisces. Dust belts are debris from collisions of larger objects such as asteroids and comets and are often described as disks of debris. Astronomers first discovered the Fomalhaut disk in 1983. But it was never as spectacular—or revealing—as Webb’s.

“I would describe Fomalhaut as an archetype of debris disks found elsewhere in our galaxy because it contains components similar to those we have in our planetary system,” said András Gaspar, assistant astronomer at the University of Arizona’s Steward Observatory. “By looking at the patterns in these rings, if we can get images deep enough to see the suspected planets, we can start to get a little sketch of what a planetary system might look like.”

The idea of ​​a protoplanetary disk around a star dates back to the late 1700s, when astronomers Immanuel Kant and Pierre-Simon Laplace independently theorized that the Sun and planets formed from a rotating cloud of gas that collapsed and flattened under the influence of gravity. . Disks of debris form later, after the formation of planets and after the dispersal of primordial gas. When small bodies such as asteroids collide, their surfaces are transformed into large clouds of dust and other debris. Observations of their dust provide unique clues about the structure of an exoplanet system that reaches Earth-sized planets and even asteroids too small to be seen individually.

Clear images of the outer belt around Fomalhaut have been previously taken by the Hubble Space Telescope, the Herschel Space Observatory, and the Atacama Large Millimeter/Submillimeter Array, or ALMA. But none of them found any structure in it. Inner belts were first detected by Webb in infrared light.

“What Webb really excels at is that we can physically separate the thermal radiation from the dust in these interior regions,” said Schuyler Wolff, Steward research professor and co-author of the paper. “So you can see inner belts that we’ve never seen before.”

“With Hubble and ALMA, we were able to image many analogs of the Kuiper belt and learned a lot about how outer disks form and evolve,” Wolff said. “But Webb should allow us to photograph a dozen asteroid belts elsewhere. We can learn as much about the warm inner regions of these disks as Hubble and ALMA have taught us about the colder outer regions.”

These belts were most likely carved by the gravitational forces created by unseen planets. Likewise, in our solar system, Jupiter occupies the asteroid belt; The inner edge of the Kuiper belt is shaped by Neptune, and its outer edge may be embraced by as yet unseen objects beyond it. As Webb views more systems, astronomers will gain a more detailed understanding of the configurations of their planets.

“The generations around Fomalhaut are a kind of mystery novel: where are the planets?” said team member George Riecke, an Arizona State University professor of astronomy and the US principal investigator for the Webb Mid-Infrared Instrument (MIRI), which made the observations. “To say that there is probably a really interesting planetary system around a star is not a big step.”