Webb Finds First Clear Evidence of Frozen Water in Young Star System

Webb Finds First Clear Evidence of Frozen Water in Young Star System
by Clarence Oxford
Los Angeles CA (SPX) May 15, 2025

Astronomers have long theorized that frozen water exists in the debris disks surrounding young stars, but definitive evidence has remained elusive - until now. Using the James Webb Space Telescope, researchers have confirmed the presence of crystalline water ice in a dusty disk orbiting a Sun-like star, HD 181327, located 155 light-years away. This finding, published in the journal Nature, represents a major breakthrough in understanding the composition of young planetary systems.

The data, captured using Webb's highly sensitive Near-Infrared Spectrograph (NIRSpec), revealed that the icy particles are distributed alongside fine dust grains, forming a mixture often described as "dirty snowballs." This crystalline water ice is similar to that found in Saturn's rings and icy bodies within our own Kuiper Belt. "Webb unambiguously detected not just water ice, but crystalline water ice," said Chen Xie, the study's lead author and assistant research scientist at Johns Hopkins University.

Previous hints of frozen water in this system came from NASA's Spitzer Space Telescope in 2008, but the older instrument lacked the sensitivity to provide conclusive proof. "When I was a graduate student 25 years ago, my advisor told me there should be ice in debris disks, but prior to Webb, we didn't have instruments sensitive enough to make these observations," said co-author Christine Chen, an associate astronomer at the Space Telescope Science Institute.

HD 181327, significantly younger than our Sun at just 23 million years old, hosts a debris disk reminiscent of our own Kuiper Belt - a region packed with icy bodies, dwarf planets, and rocky fragments. However, unlike our solar system, the water ice in this system is not evenly distributed. Researchers found that the ice concentration varies dramatically across the disk, with over 20% water ice in its outer regions and about 8% in the middle, while almost none is present near the star itself.

The study's authors suggest that ultraviolet radiation from the star likely vaporizes nearby ice, while planetesimals - large, rock-like bodies - may lock up water in their interiors, shielding it from Webb's detectors.

"This is just the beginning," Xie added. "The presence of water ice helps facilitate planet formation. Icy materials may also ultimately be 'delivered' to terrestrial planets that may form over a couple hundred million years in systems like this."

The James Webb Space Telescope, a collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA), is currently the world's most powerful space observatory, probing the farthest reaches of the cosmos.

Research Report:Water ice in the debris disk around HD 181327