Article by: Andacs Robert Eugen, on 28 August 2022, at 07:30 am Los Angeles time

Astronomers have for the first time reconstructed the history of star formation at the center of our galaxy, the Milky Way. They concluded that star birth radiated outward from the heart of the galaxy.

The results also showed that most of the young stars in the dense galactic center have moved away from it over millions of years. Using the HAWK-I infrared camera of the VLT telescope located in Chile, astronomers studied in detail an area of 64,000 square light-years around the galactic center. 

Despite the fact that there is a dense population of stars at the heart of the Milky Way, some 26,000 light-years from Earth, only a small fraction of them have been observed so far. By tracking some of the missing solar masses in the region and collecting data on 3 million stars, the researchers were able to study the qualities of these young stars for the first time. 

"Our study is a big step forward in finding young stars in the galactic center," said Francisco Nogueras-Lara, researcher and member of the research team at the Max Planck Institute for Astronomy.

"The young stars we found have a total mass of more than 400,000 solar masses, which is nearly ten times the combined mass of the two massive star clusters known so far in the central region," Nogueras-Lara said. 

The findings, which contradict previous ideas that the stars at the center of our galaxy formed in tight clusters, could help scientists better understand the rapid formation of stars as it happened in the early universe. 

To better observe the central region of the galaxy, astronomers must solve several challenges. First, the thick dust in the disk of the Milky Way obscures the core of the galaxy from view. One way to solve this is to make observations in the infrared, or radio wavelengths at which light can pass through the dust. But even so, because the galactic center is so densely populated, astronomers have difficulty distinguishing one star from another.

Until these new discoveries, astronomers had been able to locate only about 10 percent of the estimated stellar mass around the supermassive black hole at the center of the galaxy, Sagittarius A*. Using the VLT telescope, astronomers were able to examine the area in detail, which revealed that a region called Sagittarius B1 contains many more young stars than previous observations had shown.

Astronomers will now follow the rapid movement of stars in the Sagittarius B1 region around the galactic center over several years to see how their position changes. This could help to better understand how the stars were grouped together at the beginning of their existence.