European Week of Astronomy and Space Science | 2018 Apr 03
The first large-scale age-map of the Milky Way shows that a period of star formation lasting around 4 billion years created the complex structure at the heart of our galaxy. ...
The Milky Way is a spiral galaxy with a bulge at the centre, thousands of light years in diameter, that contains about a quarter of the total mass of stars. Previous studies have shown that the bulge hosts two components: a population of metal-poor stars that have a spherical distribution, and a population of metal-rich stars that form an elongated bar with a “waist”, like an x or a bi-lobed peanut. However, analyses of the ages of the stars to date have produced conflicting results. Now, an international team led by astronomers from the European Southern Observatory (ESO) have analysed the colour, brightness and spectral information on chemistry of individual stars to produce the age-map of the Milky Way. ...
The results presented are based on the analysis of three areas of the VVV infrared map, which, combined, make up the largest area studied so far in the Milky Way bulge. In all three areas, the findings on the age range of the stars are consistent. ...
The ultimate goal of this project is the construction of a map of the star formation history of the entire Milky Way bulge. ...