Astrophysicians have used AI to discover 250 new stars in the Milky Way, which they believe were born outside the galaxy.

Caltech researcher Lina Necib named the collection Nyx, after the Greek goddess of the night. She suspects the stars are remnants of a dwarf galaxy that merged with the Milky Way many moons ago.

To develop the AI, Necib and her team first tracked stars across a simulated galaxy created by the Feedback in Realistic Environments (FIRE) project. They labeled the stars as either born in the host galaxy, or formed through galaxy mergers. These labels were used to train a deep learning model to spot where a star was born.