Detailed observations of the oldest stars at the center of our galaxy, born just a billion years after the Big Bang, have been made by an international team of researchers. The results of the study were presented in National Astronomy Meeting her Royal Astronomical Society of Britain.

Some of the stars born less than a billion years after the Big Bang are still around today and can be used to study what galaxies were like when they first started to form.

Cambridge University Institute of Astronomy researcher and member of the research team, Anke Arendsen, calls them “relics from the early universe”.

These stars can be identified by their pristine chemical composition, as they are composed mainly of hydrogen and helium, with a much lower abundance of heavier elements than younger stars such as the Sun. Astronomers usually look for these ancient stars away from the plane of our galaxy’s disk, in the low-density halo around the galaxy, where they are easier to find.

Finding them in the dense inner parts of our galaxy is difficult, as our line of sight to the galactic center is blocked by large amounts of interstellar dust, and ancient stars are extremely rare compared to the abundance of younger stars.

The Pristine Inner Galaxy Survey (PIGS) team found that these stars slowly rotate around the center of our galaxy and appear to spend most of their long lives near the galactic center.

In this study, the scientists used a special imaging filter on the Canada-France-Hawaii Telescope (CFHT) and confirmed their results with spectroscopic observations with the Anglo-Australian Telescope (AAT), thus making the most detailed observations of stars in the interior of our galaxy. .

Their observations were then combined with data from the Gaia mission to study how these stars move through our galaxy. It turns out that the older the stars are, the more chaotic their motions, but even very old stars still exhibit some mean rotation around the galactic center. They also found that many of these stars spend almost their entire lives inside the galaxy, within a region that only reaches halfway between the galactic center and the Sun.