According to models of galaxy formation, it is predicted that the oldest stars would be located in the densely packed inner regions of the Milky Way. However, locating these stars in this particular area is quite difficult due to the obstruction caused by a significant amount of interstellar dust along our line of sight towards the center of the Galaxy. Additionally, ancient stars are exceptionally scarce when compared to the vast majority of their younger counterparts.

A special imaging filter was utilized by Arentsen and her team in the PIGS project on the Canada-France-Hawaii Telescope (CFHT) to effectively select potential stars. These stars were then confirmed through spectroscopic observations on the Anglo-Australian Telescope (AAT), resulting in the largest collection of detailed observations for pristine inner Galaxy stars to date. To further investigate the movement of these ancient stars within the Milky Way, the PIGS observations were combined with data from the Gaia space mission. The findings revealed that as the stars age, their motions become more chaotic. However, even the oldest stars still exhibit some average rotation around the center of the Galaxy. Additionally, it was discovered that a significant number of these stars spend the majority of their lifespan in the inner Galaxy, within a sphere that extends halfway between the galactic center and the Sun.

Arentsen expresses enthusiasm about the possibility of observing stars that originated during the initial stages of the Milky Way, which were previously difficult to study. These stars are believed to have formed shortly after the Big Bang, making them valuable remnants from the early Universe. The information available on these ancient celestial bodies is expanding at a fast pace. Arentsen eagerly anticipates the discoveries that will be made about the first stars that inhabited our Galaxy in the coming years.

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