Scientists Identify 20 Metal-Poor Milky Way Stars as Possible Remnants of Loki Merger 10 Billion Years Ago
Updated
Updated · spacedaily.com · May 27
Scientists Identify 20 Metal-Poor Milky Way Stars as Possible Remnants of Loki Merger 10 Billion Years Ago
10 articles · Updated · spacedaily.com · May 27
Twenty very metal-poor stars in the Milky Way disk have been flagged as a possible single merger remnant, with researchers proposing they came from a dwarf galaxy dubbed Loki.
Gaia Data Release 3 and Canada-France-Hawaii Telescope spectroscopy showed the 20 stars share nearly identical abundances across 23 chemical species despite split motions—11 prograde and 9 retrograde.
That unusual mix could fit a merger about 10 billion years ago, when the young Milky Way’s weaker gravity may have scattered one incoming system’s stars into both orbital directions.
The team says the Loki explanation remains provisional, with outside astronomers noting some apparent new merger signals later prove to be parts of already known structures.
If confirmed, the finding would add to evidence that the Milky Way was assembled through repeated dwarf-galaxy accretions and that key parts of its formation history are still being uncovered.
If Loki's stars are ancient immigrants, what other major events in our galaxy's formation have we missed?
Is the Milky Way's disc a graveyard of consumed galaxies, hiding more secrets than we ever imagined?
How will new telescopes rewrite the violent, cannibalistic origin story of our own galaxy?
"Unveiling Loki: How a 1.4-Billion-Solar-Mass Dwarf Galaxy Merger Changed the Milky Way Forever"
Overview
Recent astronomical research has revealed a major, previously unknown event in the Milky Way’s early history. Scientists identified a group of ancient, metal-poor stars unusually close to the galaxy’s disk. Further study showed these stars are likely remnants of a dwarf galaxy, called Loki, that merged with the young Milky Way billions of years ago. Using advanced computer simulations, researchers traced the origins of these stars and found evidence of a complex and dynamic galactic assembly. This discovery challenges earlier ideas about the Milky Way’s formation, showing it was shaped by significant early mergers.