Leibniz Institute for Astrophysics Potsdam | 2018 Sep 13
An international team of scientists led by Ivan Minchev of the Leibniz Institute for Astrophysics Potsdam (AIP) has found a way to recover the birth places of stars in our Galaxy. This is one of the major goals in the field of Galactic Archaeology, whose aim is to reconstruct the formation history of the Milky Way.Using precise stellar age and iron content measurements, the
stellar birth places could be recovered. Credit: I. Minchev (AIP)
Stars in galactic discs have long been known to wander away from their birth sites owing to a phenomenon known as “radial migration”. This movement across the Galaxy severely hampers inferences of the Milky Way formation history. Radial migration is influenced by a number of parameters that are still poorly known: for example, the size and speed of the Galactic bar, the number and shape of spiral arms in the Galactic disc, and the frequency of smaller galaxies colliding with the Milky Way during the past 10 billion years and their respective masses.
To circumvent these obstacles, the scientists devised a way of recovering the Galactic migration history using the ages and chemical composition of stars as “Archaeological artifacts”. They used the well-established fact that star formation in the Galactic disc progresses gradually outwards, following that stars born at a given position at a particular time have a distinct chemical-abundance pattern. Therefore, if the age and chemical composition (its iron content, for example) of a star can be measured very precisely, it becomes possible to directly infer its birth position in the Galactic disc without additional modeling assumptions. ...
Estimating Stellar Birth Radii and the Time Evolution of the Milky Way’s ISM Metallicity Gradient ~ I. Minchev et al