New Study Challenges Theories on Star Formation Near Black Holes
In a groundbreaking discovery, an international team of researchers has found that the star cluster IRS13 near the supermassive black hole Sagittarius A* (Sgr A*) in our galaxy is much younger than expected. This finding challenges existing theories about star formation in the vicinity of black holes and sheds new light on the history and future of our galaxy’s center.
Led by Dr. Florian Peißker at the University of Cologne’s Institute of Astrophysics, the team conducted a detailed examination of the IRS13 star cluster using data from multiple telescopes collected over several decades. This painstaking effort allowed them to identify the specific members of the cluster, which was discovered over twenty years ago.
To their surprise, the researchers found that the stars in the IRS13 cluster are only a few hundred thousand years old, incredibly young compared to our own sun, which is approximately 5 billion years old. This youthfulness presents a conundrum, as the presence of so many young stars in such close proximity to a supermassive black hole contradicts traditional understanding.
The team’s research, titled “The Evaporating Massive Embedded Stellar Cluster IRS 13 Close to Sgr A*. I. Detection of a Rich Population of Dusty Objects in the IRS 13 Cluster,” has been published in The Astrophysical Journal.
Another significant finding emerged from the study, thanks to data obtained from the James Webb Space Telescope. For the first time, the telescope produced a spectrum of the Galactic Center that was free from atmospheric interference. This breakthrough revealed the presence of water ice, typically found around young stellar objects, further supporting the young age of some stars near the black hole.
Further insights from Dr. Peißker’s team suggest that IRS13 has undergone a complex and turbulent formation history. The cluster appears to have migrated towards the supermassive black hole, influenced by factors such as friction with the interstellar medium, collisions with other star clusters, and its own internal dynamics. Eventually, the black hole’s gravitational pull captured the cluster, resulting in a bow shock formation resembling a ship’s tip cutting through water. This interaction likely triggered an increase in dust density, leading to further star formation primarily at the top or front of the cluster.
Dr. Peißker stated, “The analysis of IRS13 and the accompanying interpretation of the cluster is the first attempt to unravel a decade-old mystery about the unexpectedly young stars in the Galactic Center. In addition to IRS13, there is a star cluster, the so-called S-cluster, which is even closer to the black hole and also consists of young stars. They are significantly younger than would be possible according to accepted theories.”
Dr. Michal Zajaček, a scientist at Masaryk University in Brno (Czech Republic) and the study’s second author, added, “The star cluster IRS13 seems to be the key to unraveling the origin of the dense star population at the center of our galaxy. We have gathered extensive evidence that very young stars within the range of the supermassive black hole may have formed in star clusters such as IRS13. This is also the first time we have been able to identify star populations of different ages – hot main sequence stars and young emerging stars – in the cluster so close to the center of the Milky Way.”
The discovery of the young star cluster IRS13 near the supermassive black hole Sgr A* challenges current star formation theories and offers new insights into the complex dynamics of our galaxy’s center. It opens the door to further research on the connection between the immediate vicinity of the black hole and regions several light years away.