by scientists using the James Webb Space Telescope (JWST) have observed and measured the coldest ice in the deepest reaches of an interstellar molecular cloud to date. The frozen molecules measured minus 440 degrees Fahrenheit (minus 263 degrees Celsius), according to new research published Jan. 23 in the journal nature astronomy (opens in a new tab).
Molecular clouds, made up of frozen molecules, gases, and dust particles, serve as the birthplaces of stars and planets, including habitable planets like ours. In this latest research, a team of scientists used the JWST infrared camera to investigate a molecular cloud called Chameleon I, about 500 light-years from Earth.
Inside the cold, dark cloud, the team identified frozen molecules such as carbonyl sulfur, ammonia, methane, methanol, and more. These molecules will one day be part of the hot core of a growing star, and possibly part of future exoplanets, according to the researchers. They also contain the building blocks of habitable worlds: carbon, oxygen, hydrogen, nitrogen, and sulfur, a molecular cocktail known as COHNS.
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“Our results provide insight into the initial dark chemical stage of ice formation in interstellar dust grains that will become centimeter pebbles from which planets form,” said the study’s lead author. melissa mcclure (opens in a new tab)an astronomer at the Leiden Observatory in the Netherlands, said in a sentence (opens in a new tab).
a dusty nursery
Stars and planets form inside molecular clouds like Chameleon I. Over millions of years, gases, ice, and dust collapse into more massive structures. Some of these structures heat up to become the cores of young stars. As stars grow, they drag more and more material with them and get hotter and hotter. Once a star forms, the leftover gas and dust around it form a disk. Once again, this matter begins to collide, sticking together and eventually forming larger bodies. One day these groups may become planets. Even habitable ones like ours.
“These observations open a new window into the pathways for the formation of the simple and complex molecules needed to make the building blocks of life,” McClure said in the statement.
The JWST sent back its first images in July 2022, and scientists are currently using the $10 billion telescope’s instruments to demonstrate what types of measurements are possible. To identify the molecules within Chameleon I, the researchers used light from stars beyond the molecular cloud. As the light shines back at us, the dust and molecules within the cloud absorb it in characteristic ways. These absorption patterns can then be compared to known patterns determined in the laboratory.
The team also found more complex molecules that they cannot specifically identify. But the finding shows that complex molecules form in molecular clouds before growing stars consume them.
“Our identification of complex organic molecules, such as methanol and potentially ethanol, also suggests that many star and planetary systems developing in this particular cloud will inherit molecules in a fairly advanced chemical state,” said the study co-author. Will Rocha (opens in a new tab), an astronomer at the Leiden Observatory, said in the statement. “
Although the team was delighted to observe COHNS within the cold molecular soup, they did not find as high a concentration of molecules as they expected in a dense cloud like Chameleon I. How a habitable world like ours got its icy COHNS is still an important question. among astronomers. One theory is that the COHNS reached Earth through collisions with comets and icy asteroids.
“This is just the first in a series of spectral snapshots we will take to see how ices evolve from their initial synthesis to the comet-forming regions of protoplanetary disks,” McClure said in the statement. “This will tell us what mix of ices, and therefore what elements, may eventually be delivered to the surfaces of terrestrial exoplanets or incorporated into the atmospheres of gas or ice giant planets.”
