The central region of our galaxy is considered one of the harshest and most hostile places in the Universe. However, a new study published in the journal Astronomy & Astrophysics shows that even in the immediate vicinity of the supermassive black hole Sagittarius A*, aging stars are capable of enriching interstellar space with dust and complex molecules, including water.
The main object of the study was the aging star IRS 3, located near the Galactic center. By combining data from the infrared instruments of the James Webb Space Telescope, astronomers were able for the first time to obtain a continuous mid-infrared spectrum of this star and reveal its true chemical nature.
In the extensive gas-and-dust shells shed by the star, scientists detected clear traces of water vapor. Although water has been found near many stars in the Milky Way, this is the first time it has been detected in the immediate vicinity of the central black hole. As study co-author Macarena García Marín of the European Space Agency (ESA) noted, this demonstrates the resilience of molecular compounds even under conditions of intense radiation.
Rethinking the Nature of IRS 3
IRS 3 belongs to the so-called asymptotic giant branch — a stage in a star’s life when it expands to enormous dimensions, has a relatively low surface temperature, and exhibits high luminosity. Computer modeling revealed the following characteristics of the star:
- Age: about 72 million years.
- Mass: 6 times that of the Sun.
- Luminosity: approximately 60,000 times greater than that of the Sun.
IRS 3 was previously thought to be carbon-rich. However, detailed analysis by James Webb revealed strong signatures of silicate dust — compounds of silicon and oxygen. This overturned previous hypotheses and confirmed that the star is surrounded by a dust shell rich specifically in oxygen.
A Dust Shell in an Extreme Environment
Astronomers had long questioned whether the stellar winds of aging giants could withstand the gravity and radiation of the black hole. James Webb modeling showed that the dust shell of IRS 3 is layered and extends outward from the star over an impressive distance of about 10,000 astronomical units.
The temperature inside this shell ranges from a scorching 927°C near the surface of the star to an icy −173°C at its outer boundary. It is precisely in these more distant and colder layers that dust and water appear to be sufficiently protected to enrich the interstellar medium with elements needed for the formation of future generations of stars and planets.
Earlier, we explained what could replace water on other planets.
According to Live Science
