Hidden Dwarf Galaxy May Be Lying at the Heart of the Milky Way

A new study published in the Monthly Notices of the Royal Astronomical Society indicates that a dwarf galaxy called Loki could be hidden in the core of the Milky Way. This discovery comes after examining 20 stars with low metal content located in the galactic plane, which seem to share a common past. Astronomers believe these stars once belonged to a dwarf galaxy that was incorporated into the Milky Way during its early formation stages, contributing to its current structure.

The research compared the chemical signatures and orbits of these stars with other populations in the galactic halo and dwarf galaxies. The evidence strongly suggests they originate from an external system that played a key role in the galaxy’s early evolution. The presence of stars with very low metallicity, typical of foundational building blocks, supports this idea.

Stars with retrograde orbits can only form during the primitive stages of the Milky Way, while prograde orbits tend to be acquired through later captures.

Stars poor in metals, containing few heavy elements, serve as traces of ancient galactic mergers. Most are found in the halo, but some move within the galactic plane, like those studied here. These stars, with high eccentricity orbits, indicate an external origin, likely from systems that merged with the Milky Way in its early history.

This discovery helps us better understand how our galaxy formed and grew, revealing that its core may hide a history of mergers and acquisitions that shaped its current structure.