Like most large galaxies, ours grew by consuming smaller ones
A study of stars in the Milky Way has helped determine which ones began their lives elsewhere.
It’s long been suspected that our Galaxy grew by consuming smaller galaxies, the stars of which are still in the Milky Way. The Gaia space observatory has helped identify stellar populations whose motions indicate they may have extragalactic origins. To confirm this, astronomer Dr Sven Buder and his team at Astro 3D measured the spectra of 600,000 stars to determine their composition.
“We measured how abundant elements, such as sodium, iron, magnesium and manganese were, and how they appeared in different concentrations depending on the star’s origin,” says Buder.
The discovery is another step towards creating a picture of our Galaxy’s ‘childhood’, and understanding the size and type of galaxies it consumed as it grew. astro3d.org.au