Overview

• Direct N-body simulations show a dark star cluster model with a central black-hole subsystem can reproduce Ursa Major III’s compact structure and elevated mass-to-light ratio.
• Evolutionary tracks mapped in size–luminosity and mass-to-light diagrams place dark star clusters in the same parameter space as ambiguous faint satellites.
• Models indicate UMa III entered a dark star cluster phase about 4 billion years ago and will lose most of its luminous stars within roughly 1 billion years.
• Energy injection from centrally segregated black holes can accelerate star evaporation and produce super-virial velocity dispersions previously attributed to dark matter.
• Authors call for deeper spectroscopic, proper-motion and chemical abundance data to resolve UMa III’s true nature, as current measurements remain too sparse for definitive classification.