AssetID: 55914519
Headline: Scientists discover water near the Milky Way's central supermassive black hole
Caption: BY MARK WORGAN Astronomers have discovered that dust and water can form around the supermassive black hole at the centre of the Milky Way. Using the James Webb Space Telescope, an international team studied a dying star called IRS 3, located just 0.55 light-years from Sagittarius A*, the galaxy's central black hole. The star is nearing the end of its life and is shedding gas and dust into space through powerful stellar winds. Scientists had been unsure whether a star could continue producing this material so close to a supermassive black hole, where intense radiation creates an extremely harsh environment. The new observations provide the most detailed mid-infrared view yet of IRS 3. Using Webb's Mid-Infrared Instrument (MIRI), researchers detected oxygen-rich dust around the star. They also detected water in its surrounding envelope for the first time. The findings suggest that evolved stars can continue producing material that could eventually contribute to the formation of new stars and planets, even in the extreme conditions around a galactic centre. “Galactic centres are among the most extreme environments, so understanding whether stars can continue enriching their surroundings there is an important question,” said lead author Florian Peißker of the University of Cologne in Germany. “With Webb, we can directly observe how stars behave under these conditions and see that dust production remains remarkably resilient.” IRS 3 is one of the brightest mid-infrared sources in the centre of the Milky Way. Earlier research suggested the star might be rich in carbon. But the new Webb observations found two strong infrared signals linked to silicate dust, which is made from silicon and oxygen. The results identify IRS 3 as an oxygen-rich star in an advanced stage of its life. “This discovery was possible because of Webb’s highly capable infrared instruments,” said Macarena Garcia Marin of the European Space Agency, a co-author of the study and principal investigator of the MICONIC programme. “This is the first time a continuous mid-infrared spectrum has been collected for this star, allowing us to detect the features from the silicate dust and uncover the star’s true chemical identity.” By combining the observations with computer models, the researchers reconstructed the structure of the material surrounding IRS 3. They found layers of dust extending about 10,000 times the distance between the Earth and the Sun. Temperatures range from about 1,200 Kelvin (927C) near the star to around 100 Kelvin (-173C) in the outer regions. The observations also provided the first clear evidence of water around IRS 3. “The detection of water is especially exciting because it shows that molecular material can survive in an environment dominated by intense radiation,” said Garcia Marin. “This tells us that even close to a supermassive black hole, stars can continue contributing material back into their surroundings.” Researchers estimate that IRS 3 is about six times the mass of the Sun and around 72 million years old. The star appears to be losing mass rapidly, ejecting material into space and creating the extended dust envelope observed by Webb. The results have been published in the journal Astronomy & Astrophysics.
Keywords: feature,photo,video,milky way,black hole,space,astronomy
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