Determining How the Milky Way Formed Stars
Theories abound for how many objects in the Universe formed, including our own Milky Way galaxy. Proving one of these ideas or another can be very difficult as we have only been able to observe the Universe for a short period of time. Fortunately the impact of cosmological events can still be found millions and billions of years after the fact.
Using data from the Gaia-ESO project, researchers have found evidence to support a theory of how the Milky Way formed stars and grew. The theory predicts that stars formed much faster in the center of the galaxy then in the outer area. The data supports this by showing different metallicity between stars within the orbit of the Solar System (the Solar Circle) and those beyond it. Within the Solar Circle, stars have high concentrations of magnesium, which is typically made when a massive star quickly forms and dies young, while those outside the Solar Circle contain significantly less magnesium. This indicates that those short-lived stars formed and died in the center of the galaxy, but did not form further out.
This research also has implications with theories concerning the so-called thin and thick disks of the galaxy. These different regions are represented by objects of different ages, with the thin disk containing younger objects and the thick disk holding older objects. While such a distinction does exist, indicating the two disks also exist, there is no clear separation between them, with stars of any age and composition being found almost anywhere.
Source: University of Cambridge