Astronomers using the James Webb Space Telescope have discovered water molecules and silicate dust surviving near Sagittarius A*, the Milky Way’s central supermassive black hole. The findings, published in Astronomy & Astrophysics, show that the evolved star IRS 3 continues enriching its hostile neighborhood despite intense radiation.
At the very heart of the Milky Way, Sagittarius A* dominates a violent neighborhood defined by intense radiation, powerful winds, and severe gravitational stress. For years, scientists wondered how fragile molecules and dust grains—the essential raw materials for planets and life—could possibly survive in such an extreme sector. New observations from a space-based observatory answered that fundamental question by turning their instruments toward a massive, dying star sitting a mere 0.55 light-years from the black hole.
That star, known as IRS 3, lies about 42,000 astronomical units from the central black hole. While that distance sounds vast to everyday observers, it places IRS 3 directly in the black hole’s immediate cosmic neighborhood. Researchers using the NASA/ESA/CSA James Webb Space Telescope captured the most complete mid-infrared spectrum ever recorded for the object, revealing a dense circumstellar envelope that shields delicate chemistry from the surrounding harsh environment.
Uncovering the True Chemical Identity of IRS 3
Earlier ground-based observations left open the possibility that IRS 3 was carbon-rich, but fresh data from the telescope’s Mid-Infrared Instrument settled the debate. The spectra revealed two strong absorption features, which correspond to characteristic vibrations in silicate dust composed of silicon and oxygen.
This combination firmly classifies the aging body as an oxygen-rich evolved star. Stellar tracking places its age at about 72 million years with a mass roughly six times that of the Sun. As the star nears the end of its life, it has entered an intense period of mass loss known as the asymptotic giant branch phase, shedding gas and dust into space.
Temperatures across this structure drop dramatically, from roughly 1,200 kelvins close to the surface down to about 100 kelvins in the outer regions extending outward 10,000 astronomical units.
Water Molecules Survive Near the Supermassive Black Hole
Perhaps the most striking outcome of the observing run was the detection of water. Water and other complex molecules are notoriously fragile, easily broken apart by the ultraviolet and X-ray radiation pouring out of a black hole’s vicinity.
Finding intact water so close to the Galactic center demonstrates that the star’s dusty envelope is thick enough to shield delicate chemistry from its violent surroundings.
The observations were obtained as part of the Mid-Infrared Characterisation of Nearby Iconic galaxy Centres Guaranteed Time Observations programme. Researchers involved with the project noted that the findings reshape our understanding of how matter cycles through the densest parts of the galaxy.
Resilient Dust Production in Extreme Galactic Environments
Galactic centers were previously thought to be too hostile for evolved stars to successfully contribute raw materials back into their surroundings. The star maintains its dense, expanding envelope despite the fierce cosmic winds and radiation fields generated by Sagittarius A*.
The study highlights how stars behave under extreme conditions and proves that dust production remains remarkably resilient. By analyzing the star’s infrared light with Webb, scientists confirmed that evolved stars continue playing a vital role in supplying dust and molecules that feed future generations of stars and planets across the cosmos.
Additional analysis on the spectral features appeared in the journal Astronomy & Astrophysics, offering a fresh baseline for understanding stellar evolution near the Milky Way’s central black hole.
