Science

The James Webb Space Telescope has discovered the coldest interstellar ice ever seen.

NASA’s latest space telescope not only expands astronomers’ field of view deep into the universe, but also reaches cooler temperatures than ever before.

The James Webb Space Telescope (JWST or Webb), the most powerful space-based observatory, has peered deep into the dense molecular cloud and discovered a rich variety of pristine interstellar ice, including a range of molecules critical to life. Found at minus 440 degrees Fahrenheit (minus 263 degrees Celsius), these finds are the coldest ice ever measured.

“We just couldn’t have observed these ices without Webb,” said Klaus Pontoppidan, an astronomer at the Space Telescope Science Institute and author of a new study describing the work.

Related: Best James Webb Space Telescope images of all time (Gallery)

View of the Chameleon I cloud from the James Webb Space Telescope. (Image credit: NASA, ESA, CSA and M. Zamani (ESA/Webb); Science: M. C. McClure (Leiden Observatory), F. Sun (Steward Observatory), Z. Smith (Open University) and Ice Age ERS . Command.)

Webb studied the area that scientists call Chameleon I. Located in the southern constellation Chameleon, about 500 light-years from Earth, it is one of the closest star-forming regions with dozens of pockets filled with young stars. The region belongs to a family of what astronomers have long believed to be holes in the sky: dark molecular clouds so dense with gas and dust that visible light from background stars cannot penetrate them.

Clouds like Chameleon I are stellar mangers; their collapse over time forms stars and potentially solid planetary systems. However, the chemistry of these systems, and any building blocks of life they may contain, is determined by ices trapped deep within the molecular cloud.

Now, thanks to Webb’s powerful tools, including his deep-penetrating near-infrared camera (NIRCam), astronomers have examined the dusty heart of Chameleon I and found ices early in their evolution — just before the cloud’s core collapses to form protostars.

The team used light from two background stars, NIR38 and J110621, to illuminate Chameleon I in the infrared. Various cloud molecules encased in ice absorb starlight at various infrared wavelengths. The astronomers then studied the chemical fingerprints, which appeared as dips in the resulting spectral data. This data helped the team determine how many molecules are present in Chameleon I.

Flawless Cloud Ice

The team found an expected set of key life-sustaining compounds: water, carbon dioxide, carbon monoxide, methane, and ammonia. The observations also revealed signs of carbonyl sulfide ice, allowing the first measurements of how much sulfur — another element essential to at least life on Earth — is present in molecular clouds. The researchers also discovered the simplest complex organic molecule, methanol, which is considered a clear indicator of the complex early chemical processes that occur during the early stages of star and planet formation.

“Researchers have been able to study the composition of so-called prestellar ices near the center of a molecular cloud for the first time,” says Melissa McClure, an astronomer at the Leiden Observatory in the Netherlands and lead author of the study. said in the second statement.

Three different instruments aboard the James Webb Space Telescope analyzed materials in the Chameleon I cloud.

Three different instruments aboard the James Webb Space Telescope analyzed materials in the Chameleon I cloud. (Image credit: NASA, ESA, CSA and J. Olmsted (STScI))

The fact that the team discovered methanol suggests that the stars and planets that will eventually form in this cloud “inherit molecules in a fairly advanced chemical state,” Will Rocha, another astronomer at the Leiden Observatory, said in a statement. “This could mean that the presence of prebiotic molecules in planetary systems is a common result of star formation, rather than a unique feature of our own solar system.”

In addition, methanol can be combined with other simpler ices to form amino acids, which are the building blocks of proteins. These compounds may include glycine, one of the simplest amino acids. In 2016, the European spacecraft Rosetta detected glycine in the dust surrounding comet 67P/Churyumov-Gerasimenko.

Why dust grains and ice are important for creating habitable exoplanets

Molecular clouds like Chameleon I start out as diffuse regions of dust and gas. On the surface of dust grains, ices form, containing important molecules necessary for life, including the latest discoveries of astronomers.

As clouds accumulate into clumps of gas and move towards star formation, these ices increase in size, remaining layers on dust grains. Many of the chemical reactions necessary to form the complex molecules necessary for life are accelerated when they occur on a solid surface, such as a grain of dust, rather than in gaseous form. In this way, dust particles become the most important catalysts for the transformation of simple organic elements into complex molecules that can eventually become the building blocks of life.

What’s more, as stars begin to form and temperatures rise, the volatile nature of these ices allows them to turn back into gases, which is how they end up in hot stellar cores and eventually planetary atmospheres. The discovery of these pristine ices inside Chameleon I allows astronomers to trace the journey of the compounds, from dwelling on dust grains to embedding themselves into the cores and atmospheres of future stars and exoplanets.

With Webb’s data, astronomers already know that the group of discovered elements in Chameleon I is much less common than scientists expected, given the density of the cloud. For example, the researchers found only 1% of the expected sulfur, 19% of the predicted oxygen and carbon, and only 13% of the predicted total nitrogen. The best explanation, the researchers note in the study, is that these elements could be captured by other ices that do not show up in the wavelengths observed by the team.

In the coming months, the team plans to use Webb’s data to calculate dust particle sizes and ice shapes.

“These observations open a new window on how the simple and complex molecules that are needed to create the building blocks of life are formed,” said McClure.

The study is described in the article (will open in a new tab) published on Monday (January 23) in the journal Nature Astronomy.

Follow Sharmila Kuthunur on Twitter @Sharmilakg. Follow us on Twitter @Spacedotcom and on Facebook.

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