The James Webb Space Telescope (JWST) has made a groundbreaking discovery that challenges our understanding of stellar evolution and the role of supermassive black holes in the galaxy. In a recent study published in Astronomy & Astrophysics, researchers have found evidence of a dying star, IRS 3, located surprisingly close to the supermassive black hole at the center of the Milky Way.
This finding is particularly exciting because it suggests that stars can continue to enrich their surroundings even in the harsh conditions near a supermassive black hole. The study, led by Florian Peißker, an astrophysicist at the University of Cologne, Germany, used JWST's Mid-Infrared Instrument (MIRI) to observe the inner parsec of the Milky Way, focusing on the dying star IRS 3.
IRS 3 is an asymptotic giant branch (AGB) star, meaning it is in a late stage of its life. Its powerful stellar winds blast its outer layers into space at an estimated speed of 15 kilometers per second, creating an immense dusty envelope that extends 10,000 astronomical units (AU) from the star.
The researchers ran multiple simulation variations to reconcile JWST's observations with stellar models across a range of temperatures, luminosities, and chemical compositions. Based on these models and observations, they inferred that IRS 3 may have been born as far away as 16 light-years from the galactic center and migrated inward. It could be about six times as massive as the Sun and approximately 72 million years old.
Despite its relatively low effective temperature of 2800 K, IRS 3 may shine 60,000 times brighter than our Sun. This work demonstrates that such stars can keep supplying chemically rich space dust and water to galactic centers, despite harsh conditions. The detection of water is especially exciting because it shows that molecular material can survive in an environment dominated by intense radiation.
The study also reveals that as the star pulses in its death throes, it 'coughs up' its bloated outer layers, creating a nesting-doll-like set of shells at intervals of hundreds of years, potentially dating back to 5,000 years ago. This finding suggests that even close to a supermassive black hole, stars can continue contributing material back into their surroundings.
In my opinion, this discovery is a significant step forward in our understanding of stellar evolution and the role of supermassive black holes in the galaxy. It challenges our previous assumptions and highlights the resilience of stars in even the most extreme environments. As we continue to explore the cosmos with the JWST, we can expect to uncover more fascinating insights into the mysteries of the universe.
