A dying star in an extreme environment

IRS 3 is an evolved star approaching the end of its life. It belongs to a stage known as the asymptotic giant branch, or AGB phase.

Stars in this stage become enormous, cool and extremely bright. They also lose large amounts of material through powerful stellar winds, releasing gas and dust into surrounding space.

This process is important on a cosmic scale. The material released by aging stars becomes part of the raw ingredients that can eventually contribute to new stars, planets and other astronomical objects.

But IRS 3 is in a particularly hostile neighborhood.

The star is located close to Sagittarius A*, the supermassive black hole at the center of the Milky Way. Astronomers have therefore wondered whether a star could continue producing and retaining dust under such intense conditions.

Webb appears to have provided the answer.

Webb detects oxygen-rich dust

The observations were made using Webb’s Mid-Infrared Instrument, known as MIRI. Infrared observations are especially useful for studying relatively cool dust and molecules that can be difficult to detect at visible wavelengths.

The telescope detected strong infrared signatures associated with silicate dust around IRS 3.

Silicates are minerals containing silicon and oxygen, and they are important components of cosmic dust. The discovery also showed that IRS 3 is an oxygen-rich evolved star, correcting earlier suggestions that it might instead be carbon-rich.

For researchers, this was an important clue about what is actually happening around the star.

And then Webb found water

Perhaps the most surprising part of the observations was the detection of water in the material surrounding IRS 3.

Astronomers had expected the intense radiation near the Milky Way’s central black hole to make it difficult for molecules such as water to survive.

Instead, Webb found clear evidence of water within the star’s surrounding envelope.

That means molecular material can exist even in an environment dominated by intense radiation.

The discovery gives scientists a new look at how stars behave close to supermassive black holes — and suggests that these extreme regions may not be quite as destructive to stellar material as previously thought.

A huge shell of material surrounds the star

By combining Webb’s observations with computer models, the researchers reconstructed the structure of the material surrounding IRS 3.

The dust appears to be distributed in layers or shells extending roughly 10,000 astronomical units from the star.

Temperatures within this envelope vary dramatically. Material close to IRS 3 can reach around 1,200 kelvin, while the outer regions are much cooler, reaching roughly 100 kelvin.

This enormous envelope is essentially the material the aging star is shedding into space.

A six-Sun-mass star nearing the end

The researchers estimate that IRS 3 has a mass of about six times that of the Sun and is approximately 72 million years old.

The star is currently undergoing significant mass loss, ejecting material into its surroundings and creating the extended dusty envelope observed by Webb.

Although the star is relatively close to the Milky Way’s central black hole, its ongoing activity shows that stellar evolution can continue even under these extreme conditions.

Why this discovery matters

Dust is one of the fundamental ingredients of the universe.

Tiny grains of cosmic dust can become part of clouds from which new stars and planets eventually form. Over billions of years, material produced by older generations of stars can therefore be recycled into new planetary systems.

The new Webb observations suggest that evolved stars in the crowded centers of galaxies may contribute more dust and material to their surroundings than scientists previously expected.

In other words, even near a supermassive black hole, dying stars may still be helping to enrich their cosmic neighborhood.

Webb’s ability to see in infrared wavelengths is making it possible to study these processes in remarkable detail.

The observations of IRS 3 were collected in 2025 as part of the MICONIC observing programme and were published on August 11, 2026, in Astronomy & Astrophysics.

The bigger picture

The center of the Milky Way is often portrayed as a violent and inhospitable place dominated by the enormous gravitational pull of Sagittarius A*. But Webb’s observations of IRS 3 reveal a more complicated picture.

Even in this extreme environment, an aging star can continue losing material, producing dust and retaining water.

It is another example of how the James Webb Space Telescope is revealing unexpected details about how stars live, die and recycle material throughout the universe.