NASA says it was able to use the James Webb telescope to capture images of planet-forming disks around ancient stars that challenge theoretical models of how planets can form. The images support earlier findings from the Hubble telescope that haven’t been able to be confirmed until now.
The new Webb highly detailed images were captured from the “Small Magellanic Cloud,” a neighboring dwarf galaxy to our home, the Milky Way. The Webb telescope was specifically focused on a cluster called NGC 346, which NASA says is a good proxy for “similar conditions in the early, distant universe,” and which lacks the heavier elements that have traditionally been connected to planet formation. Webb was able to capture a spectra of light which suggests protoplanetary disks are still hanging out around those stars, going against previous expectations that they would have blown away in a few million years.
“Hubble observations of NGC 346 from the mid 2000s revealed many stars about 20 to 30 million years old that seemed to still have planet-forming disks,” NASA writes. Without more detailed evidence, that idea was controversial. The Webb telescope was able to fill in those details, suggesting the disks in our neighboring galaxies have a much longer period of time to collect the dust and gas that forms the basis of a new planet.
As to why those disks are able to persist in the first place, NASA says researchers have two possible theories. One is that the “radiation pressure” expelled from stars in NGC 346 just takes longer to dissipate planet-forming disks. The other is that the larger gas cloud that’s necessary to form a “Sun-like star” in an environment with fewer heavy elements would naturally produce larger disks that take longer to fade away. Whichever theory proves correct, the new images are beautiful evidence that we still don’t have a full grasp of how planets are formed.
