The Webb telescope team has detected water ice and frozen complex molecules in a molecular cloud about 630 light-years from Earth. By the scientists’ measure, the frigid findings are the deepest, coldest yet found in such a cloud.
Molecular clouds are large, dark, dusty regions of space that often act as stellar nurseries, as they host the ingredients necessary for star formation. The clouds also host organic molecules; last year, researchers peering at a molecular cloud near the centre of our galaxy found building blocks of RNA, a molecule found in all living cells.
Among the bevy of molecules detected in the cloud were water, methane, ammonia, and complex molecules like methanol. The researchers said they also found evidence for chemicals even more complex than methanol, though they didn’t identify the specific molecules. Their findings are published today in Nature Astronomy.
The research is part of the Ice Age project, one of Webb’s ongoing Early Release Science programs. These are the first projects on Webb’s docket, which kicked off with the telescope’s debut full-colour images back in July 2022.
“Our results provide insights into the initial, dark chemistry stage of the formation of ice on the interstellar dust grains that will grow into the centimeter-sized pebbles from which planets form in disks,” said study author Melissa McClure, an astronomer at Leiden Observatory in the Netherlands, in a NASA press release.
Because molecular clouds are so dark and cold, researchers image their interiors using light from background stars, which can permeate the clouds. Molecules within the clouds absorb the starlight, allowing us to deduce the which chemicals are present based on dips in specific wavelengths of light.
The cloud the team focused on is named Chamaeleon I, one of several in the Chamaeleon Cloud Complex. It’s not the first time Chamaeleon I has been imaged; last year, the Hubble Space Telescope captured young, blue stars peering through the wispy dust.
“We simply couldn’t have observed these ices without Webb,” said Klaus Pontodippan, a Webb project scientist at the Space Telescope Science Institute and a co-author of the research, in the NASA release. “Webb’s exquisite sensitivity was necessary to detect the starlight and therefore identify the ices in the molecular cloud.”
The Webb data contains information about the constituent molecules lying within Chamaeleon I that Hubble is not capable of seeing, which can teach us about the conditions in which such ices form, as well as how those ices contribute to the formation of larger structures, like planets and their atmospheres.
McClure added that the new data is “just the first in a series of spectral snapshots,” so the team will almost certainly have more details about the composition of such enigmatic space clouds in the near future.
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