As well as helping us learn about the earliest galaxies in the universe and taking stunning images of parts of our solar system, the James Webb Space Telescope is also letting astronomers learn more about how planets form. Although we know that planets form from disks of dust and gas around stars called protoplanetary disks, there’s still a lot we don’t know about this process, particularly about how forming planets affect the rest of the system around them.
So it was an exciting moment when astronomers recently used Webb to study an asteroid belt in another planetary system and were able to peer into the rings of dust around the star to see where planets were forming.
Webb was used to study to study the Fomalhaut star, located in the constellation Piscis Austrinus, which is forming planets in a manner that is similar to what happened in our solar system around 4 billion years ago. The forming planets themselves aren’t visible, but the researchers could infer their presence based on the gaps in the dusty disk. They saw three concentric disks stretching a total of 14 billion miles from the star.
“I would describe Fomalhaut as the archetype of debris disks found elsewhere in our galaxy, because it has components similar to those we have in our own planetary system,” said lead researcher András Gáspár of the University of Arizona in Tucson in a statement. “By looking at the patterns in these rings, we can actually start to make a little sketch of what a planetary system ought to look like — if we could actually take a deep enough picture to see the suspected planets.”
Astronomers had previously looked at this system with Hubble, but had only been able to see the outer ring, but with Webb’s more powerful infrared instruments, it was able to see the warm glow of the dust from the interior rings as well. That supports the idea that there are planets there, even if they can’t be seen yet.
“We definitely didn’t expect the more complex structure with the second intermediate belt and then the broader asteroid belt,” said co-author Schuyler Wolff. “That structure is very exciting because any time an astronomer sees a gap and rings in a disk, they say, ‘there could be an embedded planet shaping the rings!’”
This effect is similar to the way that Jupiter marks the end of the asteroid belt in our solar system, as small asteroids are either pushed away or absorbed into the planet. By studying distant star systems like Fomalhaut, we can learn about how our own solar system evolved.
The research is published in the journal Nature Astronomy.
