The James Webb Space Telescope (JWST) has made a groundbreaking discovery, revealing that water can survive remarkably close to our galaxy's supermassive black hole. This finding is particularly exciting as it challenges our understanding of the harsh conditions near such extreme objects. The JWST's Mid-Infrared Instrument (MIRI) observed a dying star, IRS 3, located just 0.55 light-years from Sagittarius A*, the supermassive black hole at the heart of the Milky Way. This star, an asymptotic giant branch (AGB) star, is in its late stages of life, losing its outer layers into space due to powerful stellar winds.
Florian Peißker, an astrophysicist at the University of Cologne, emphasizes the significance of this discovery. "Galactic centers are among the most extreme environments, so understanding whether stars can continue enriching their surroundings there is an important question. With Webb, we can directly observe how stars behave under these conditions and see that dust production remains remarkably resilient."
The researchers ran simulations to reconcile the JWST's observations with stellar models, considering various temperatures, luminosities, and chemical compositions. They inferred that IRS 3 may have been born 16 light-years from the galactic center and migrated inward. It is estimated to be six times as massive as the Sun and approximately 72 million years old, a relatively young star compared to the Sun's expected lifespan.
Despite its lower effective temperature of 2800 K, IRS 3 shines 60,000 times brighter than our Sun. This star's death throes are particularly fascinating. As it pulses, it 'coughs up' its bloated outer layers, creating a series of shells at intervals of hundreds of years, potentially dating back 5,000 years. Macarena Garcia Marin, an ESA scientist for Webb's MIRI instrument, highlights the detection of water as especially exciting, as it demonstrates that molecular material can survive in an environment dominated by intense radiation.
This research, published in Astronomy & Astrophysics, demonstrates that stars can continue to supply chemically rich space dust and water to galactic centers, even in the harsh conditions near supermassive black holes. It opens up new avenues for exploration, as the mixing of star-borne water and other star-stuff with radiation could lead to the formation of unique cosmic compounds. As Garcia Marin concludes, "This tells us that even close to a supermassive black hole, stars can continue contributing material back into their surroundings."
The discovery is a testament to the power of the JWST and the ongoing advancements in our understanding of the universe. It raises intriguing questions about the potential for life and the formation of complex molecules in the most extreme environments of our galaxy.
