Potential impact of the Sagittarius dwarf galaxy on the formation of young O-rich stars.

ABSTRACT: The Milky Way underwent significant transformations in its early history, characterised by violent mergers and satellite galaxy accretion. However, recent observations reveal notable star formation events over the past 4 Gyr, likely triggered by perturbations from the Sagittarius dwarf galaxy. Here, we present chemical signatures of this accretion event, using the [Fe/H] (metallicity) and [O/Fe] (oxygen abundance) ratios of thin-disc stars. In the normalised age-metallicity plane, we identify a discontinuous V-shape structure at zmax (maximum vertical distance from the disc plane)  < 0.4 kpc in the local disc, interrupted by a star formation burst between 4 and 2 Gyr ago. This event is characterised by a significant increase in oxygen abundance, resulting in a distinct [O/Fe] gradient and

SUBMITTER: Sun T 

PROVIDER: S-EPMC11822012 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature