Milky Way neighbours “ripped out” by colliding galaxy | Cosmos
Stars currently orbiting the Milky Way were violently ripped from our own galaxy by an invading satellite galaxy, astronomers have discovered.
When galaxies pass close by to each other, massive gravitational forces fling stars, dust and gas around like a giant cosmic blender. These interactions can dramatically distort a galaxy’s structure and shape, and even influence its future evolution. The Milky Way has led an active and often violent life with many close gravitational shaves; its iconic spiral structure may even be the result of one such tussle.
Now an international team of astronomers, led by Maria Bergemann from the Max Planck Institute for Astronomy in Germany, has studied two groups of stars in the stellar halo that encircles the Milky Way’s star-studded spiral disc. The chemical composition of these stars was found to closely match those in the galactic disc, providing compelling evidence that they have been evicted from their original birthplace in the Milky Way.