In a landmark discovery, NASA’s James Webb Space Telescope (JWST) has detected frozen water in a young star system located 155 light-years from Earth.
This marks the first confirmed observation of water ice outside our solar system, according to findings published in Nature.
The ice was found in a dusty debris disk orbiting a young star named HD 181327, which is about 23 million years old. Slightly more massive and hotter than our Sun, HD 181327 hosts a planetary system that appears to resemble the early stages of our own solar system’s development.
Crucially, the water was identified as crystalline water ice, the same form found in places like Saturn’s rings and the icy objects within the Kuiper Belt — the distant, icy region of our solar system.
"Webb unambiguously detected not just water ice, but crystalline water ice, which is also found in locations like Saturn's rings and icy bodies in our solar system's Kuiper Belt," said Chen Xie, the study’s lead author.
The JWST’s instruments revealed a prominent gap between the star and its icy debris disk, echoing the structure of our Kuiper Belt. Within the disk, frequent collisions between icy objects are believed to release fine particles of water ice, which Webb’s sensitive detectors were able to capture.
"HD 181327 is a very active system. There are regular, ongoing collisions in its debris disk. When those icy bodies collide, they release tiny particles of dusty water ice that are perfectly sized for Webb to detect," Xie explained.
Interestingly, the distribution of the ice is uneven. Most of it is concentrated in the colder, outer regions of the disk, furthest from the star. In the central area of the disk, about eight percent of the material detected was water ice, suggesting that in this zone, ice is being created slightly faster than it's breaking down.
"Toward the middle of the debris disk, Webb detected about eight per cent water ice. Here, it's likely that frozen water particles are produced slightly faster than they are destroyed."
The discovery adds weight to theories that planetary systems across the universe may evolve in similar ways. The similarities between HD 181327’s structure and our own solar system suggest that the processes leading to the formation of planets and water-bearing bodies could be common.
Previously, astronomers suspected that debris disks might contain frozen water, but lacked the tools to confirm it. With JWST’s breakthrough observation, researchers are now expected to expand their search for water ice in young, evolving star systems throughout the Milky Way.