NASA reports that the James Webb Space Telescope has captured images of planet-forming disks around ancient stars that challenge theoretical models of planet formation. The images confirm the previous findings of the Hubble telescope, which have not been confirmed until now.
The new highly detailed Webb images were obtained 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 heavy elements traditionally associated with planet formation. Webb was able to capture light spectra that indicate that protoplanetary disks are still orbiting these stars, contrary to previous expectations that they should have scattered within a few million years.
“Hubble’s observations of NGC 346 since the mid-2000s have revealed many stars 20 to 30 million years old that appear to still have planet-forming disks,” NASA writes. Without more evidence, this idea was controversial. The Webb telescope was able to fill in those details, suggesting that disks in our neighboring galaxies have a much longer period of time to collect the dust and gas that form the basis of a new planet.
As for why these disks are able to exist at all, NASA says researchers have two possible theories. One is that the “radiation pressure” displaced by the stars in NGC 346 simply takes longer to disperse the planet-forming disks. Another is that the larger gas cloud needed to form a “sun-like star” in an environment with fewer heavy elements naturally forms larger disks that take longer to fade away. Whichever theory turns out to be correct, the new images are excellent proof that we still don’t have a complete picture of how planets form.
