Stream of Stars From Beyond Milky Way Found Moving Toward Galaxy Center
Researchers have found a stream of stars that appear to be from beyond our galaxy moving toward the center of the Milky Way. (iStock)
By: Hannah Osborne
A "vast" stream of stars that appear to have come from outside the Milky Way has been discovered moving toward the galaxy center. Researchers believe the stream, which contains around 200 stars, is the result of a merger event between the Milky Way and a dwarf galaxy, with the latter being consumed by our home galaxy a long time ago.
Lina Necib, a Postdoctoral Fellow at the California Institute of Technology, and colleagues were attempting to build a catalog of stars in the Milky Way that were born outside the galaxy. They created a machine learning program that can distinguish between stars from the Milky Way and those from outside it. They used this to look at data from Gaia, a mission to categorize one billion stars in the Milky Way.
Necib had initially been interested in building a link between dark matter, the mystery form of matter that makes up most of the universe, and stars. Scientists had previously found evidence to suggest the kinematics—which describes motion without reference to the force causing it—of dark matter were correlated with accreted stars. These are stars born in other galaxies and brought in through mergers.