With the help of the ANU Skymapper, Australian astronomers have found out that the retirement home for stars might just be in the middle of our very own Milky Way. These stars seem to date back 13.6 billion years and are what scientists call “anemic” stars.
The Skymapper is a state-of-the-art automated wide-field telescope belonging to the Australian National University Research School of Astronomy and Astrophysics and it helped with the process of finding these elusive stars. Without it, this search could have been as laborious as finding a needle in a solar system sized haystack, due to the sheer number of stars in our galaxy. The Skymapper used a process similar to spotting the odd one out, by looking for the specific color of anemic stars, considerably shortening this search.
Stars are called anemic when their iron levels are way lower than normal stars, thus giving them a specific color that the Skymapper can specifically target and identify (they look slightly bluer than other stars). The younger a star is, the more iron it has, due to the process in which a star “dies”. The supernova which comes with the death of a star releases gases and iron into space, elements that in time for new stars and planets, so if there are more stars that can die, the quantity of iron in our galaxy grows more and more, thus making new stars rich in iron, compared to their older sisters.
The stars found in the middle of our galaxy have been there even before the Milky Way was even born but remained in about the same place throughout their entire lives. Scientists used telescopes in Australia and Chile in order to predict where the stars have moved since their birth and it showed that they really haven’t moved that much. Stars like these date to when our Universe was very young.
Another way to specifically identify a select group of stars is to study their exact “fingerprint” given by the elements that make them what they are. Every element gives off a feedback, as distinct as different colors of light in the spectrum, thus creating their specific fingerprint.
By studying these stars, scientists hope to find more and more information about the birth of our Universe and how things have evolved in order to become what they are today. One of the ways you can look to what the future might bring is to look at how the past came to be, thus triggering the need to find these old stars. To their surprise and with the help of the ANU Skymapper, the retirement home for stars might just be in the center of our very own Milky Way.