Dark star clusters or extreme dwarf galaxies? Astrophysicists revisit Ursa Major III’s true nature

Ursa Major III, the faintest object in our galaxy, orbits the Milky Way at a distance of more than 30,000 light years. Until now, it was considered a dwarf galaxy, thought to consist mainly of dark matter due to its large mass. However, an international team of astrophysicists from the University of Bonn and the Institute for Advanced Studies in Basic Sciences in Iran has found evidence suggesting that it is actually a compact star cluster containing a black hole core. The study has been published in The Astrophysical Journal Letters.