... Stellar archaeology traces Milky Way's history . By studying white dwarfs in our galaxyт??s halo, astronomers reinforced the view that this area of the Milky Way is composed of a layer-cake structure that formed in stages over billions of years. ... Astronomers have proposed that the Milky Way's halo is composed of two populations of stars. ... Using a new technique, Kalirai probed the burned-out relics of Sun-like stars, called white dwarfs, in the inner region of our Milky Way Galaxy's halo. ...