The astronomers finding was made using data from ESAs Gaia space telescope, which launched in December 2013.
The teams analysis of the Gaia data waspublishedlast month in Monthly Notices of the Royal Astronomical Society.
The region of interest in the Gaia data is the Milky Ways inner stellar halo.
An artist’s impression of the Gaia spacecraft, the Milky Way in background.Illustration:Spacecraft: ESA/ATG medialab; Milky Way: ESA/Gaia/DPAC. Acknowledgement: A. Moitinho.
This area features a stretch with a high concentration of iron and hydrogen.
The stars in this stretch have eccentric orbits compared to the surrounding stars.
Its a sort of cosmicBenjamin Button, getting less wrinkly over time.
The Milky Way’s halo of stars as seen by Gaia (left), and how it would look if a merger happened in the ancient past.Image:Halo stars: ESA/Gaia/DPAC, T Donlon et al. 2024; Background Milky Way and Magellanic Clouds: Stefan Payne-Wardenaar
The three-billion-year-old collision likely occurred between the Milky Way and a dwarf galaxy, Donlon added.
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