Nitrogen-rich field stars are not necessarily old

Globular cluster (GC) stars exhibit distinct chemical abundance patterns, which can classify them into multiple stellar populations. When red giant stars with these chemical signatures are discovered in the Galactic field, rather than within GCs, they are assumed to have once belonged to GCs. We have expanded the search for such chemically peculiar stars in the Kepler field, targeting metal-poor stars located in the halo, thin and thick disk, combining asteroseismic properties with chemical abundances and kinematics, in order to investigate their potential origins. Combining data from APOGEE DR17, Gaia DR3, and Kepler, we have identified a sample containing: primordial stars - with chemical signatures typical of field stars, and enriched stars - with strong nitrogen enrichment and corresponding carbon and oxygen depletion. The asteroseismic ages of stars in our sample indicate that most of the enriched stars are too young to have originated from globular clusters. This has prompted a search for alternative explanations of their origins, such as enrichment through a binary companion, which could mimic the enrichment signature observed in GCs.