Overview
- Researchers identify a distinct population of globular clusters that they say came from a dwarf galaxy, which was accreted by the Milky Way roughly 11.8 to 12 billion years ago.
- The finding rests on deep Hubble photometry for precise cluster ages and chemical content combined with Gaia astrometry to separate cluster groups by origin.
- The team estimates the progenitor, dubbed Low-energy–Kraken–Heracles or LKH, had about 5 × 10^8 times the mass of the Sun, comparable to the present-day Sagittarius dwarf.
- The merger likely delivered stars, gas and dark matter that could have sparked new star formation and altered the Milky Way’s chemical mix as those stars evolved and died.
- Authors warn the result is limited by current sampling, note the informal naming of the progenitor, and say deeper, wider surveys could reveal additional early mergers.