The oldest of these stars is 1.5 billion years old while the youngest is only 100 million years old, according to a paper published in the Astrophysical Journal Letters.
The center of our Milky Way Galaxy, approximately 27,000 light-years away in the constellation of Sagittarius, is a crowded place.
This region is so tightly packed that it is equivalent to having one million stars crammed into the volume of space between the Sun and Alpha Centauri, located 4.3 light-years away.
This nuclear star cluster surrounds Sagittarius A*, the 4.3-million-solar-mass black hole at the center of the Galaxy.
In general, many nuclear star clusters coexist with supermassive black holes, and can be found in more than 70% of galaxies with masses above 100 million – 10 billion solar masses.
“In a previous study, we put forward a hypothesis that these specific stars in the middle of the Milky Way could be unusually young,” said Lund University astronomer Rebecca Forsberg.
“We can now confirm this. In our study we have been able to date three of these stars as relatively young, at least as far as astronomers are concerned, with ages of 100 million to about 1 billion years.”
“This can be compared with the Sun, which is 4.6 billion years old.”
In the study, Dr. Forsberg and her colleagues used high-resolution data from the Keck II telescope in Hawaii, one of the world’s largest telescopes with a mirror ten metres in diameter.
For further verification, they then measured how much of the heavy element, iron, the stars contained.
The element is important for tracing the galaxy’s development, as the theories the astronomers have about how stars are formed and galaxies develop indicate that young stars have more of the heavy elements, as heavy elements are formed to an increasing extent over time in the Universe.
To determine the level of iron, the astronomers observed the stars’ spectra in infrared light which, compared with optical light, are parts of the light…
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