Streams of stars orbiting the Milky Way shed light on galaxy’s dark matter

Stellar groupings orbiting in the outskirts of the Milky Way shed new light on the evolution of our galaxy as well as the elusive dark matter that surrounds it.

Scientists from the Carnegie Institution for Science mapped a dozen associations of stars that orbit within the gaseous halo that envelopes our galaxy, the Milky Way. The stars form elongated threads, called stellar streams, which arc around the host galaxy’s edges. Studying these stellar structures helps astronomers better understand the distribution of dark matter in our galaxy and retrace how the galaxy grew over time by devouring smaller groups of stars.