Not all nitrogen-rich field stars originate from globular clusters

Fuente: arXiv
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Main Authors: Leitinger, Ellen I., Miglio, Andrea, Montalbán, Josefina, Massari, Davide, Bragaglia, Angela, van Rossem, Walter E., Brogaard, Karsten, Mazzi, Alessandro, Thomsen, Jeppe Sinkbæk, Willett, Emma
Format: Preprint
Published: 2026
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author Leitinger, Ellen I.
Miglio, Andrea
Montalbán, Josefina
Massari, Davide
Bragaglia, Angela
van Rossem, Walter E.
Brogaard, Karsten
Mazzi, Alessandro
Thomsen, Jeppe Sinkbæk
Willett, Emma
author_facet Leitinger, Ellen I.
Miglio, Andrea
Montalbán, Josefina
Massari, Davide
Bragaglia, Angela
van Rossem, Walter E.
Brogaard, Karsten
Mazzi, Alessandro
Thomsen, Jeppe Sinkbæk
Willett, Emma
contents Globular clusters (GCs) are important tracers of the early Galactic assembly process, with part of their stars showing distinct chemical abundance patterns. When such stars are found in the Galactic field rather than within GCs, they are assumed to have originated from clusters. We expand the search for such chemically enriched stars in the Kepler field, targeting stars located in the halo, thin and thick disc, to show the potential in using asteroseismology to link the inferred masses and hence, ages, with chemical abundances and kinematics. Using data from APOGEE DR17, Gaia DR3, and the Kepler mission, we identify primordial stars as those with chemical signatures typical of field stars, and enriched stars as those exhibiting strong nitrogen enrichment, with corresponding carbon and oxygen depletion. We present our sample of 133 red giant branch and core-He-burning stars, 92 of which have measured masses and inferred age estimations from asteroseismology. Of the 20 enriched stars identified, 13 have precise asteroseismic ages, of which a maximum of 3 are old enough ($> 8$ Gyr) to plausibly originate from globular clusters. The inferred asteroseismic ages indicate that most enriched stars found in the field appear too young to have originated from GCs; however, these apparently young ages are likely the result of assuming single-star evolution, rather than accounting for binary interactions or mergers. This points to alternative enrichment and evolutionary scenarios, such as mass transfer or coalescence, rather than a globular-cluster origin for most field nitrogen-rich stars.
format Preprint
id arxiv_https___arxiv_org_abs_2603_02327
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Not all nitrogen-rich field stars originate from globular clusters
Leitinger, Ellen I.
Miglio, Andrea
Montalbán, Josefina
Massari, Davide
Bragaglia, Angela
van Rossem, Walter E.
Brogaard, Karsten
Mazzi, Alessandro
Thomsen, Jeppe Sinkbæk
Willett, Emma
Astrophysics of Galaxies
Globular clusters (GCs) are important tracers of the early Galactic assembly process, with part of their stars showing distinct chemical abundance patterns. When such stars are found in the Galactic field rather than within GCs, they are assumed to have originated from clusters. We expand the search for such chemically enriched stars in the Kepler field, targeting stars located in the halo, thin and thick disc, to show the potential in using asteroseismology to link the inferred masses and hence, ages, with chemical abundances and kinematics. Using data from APOGEE DR17, Gaia DR3, and the Kepler mission, we identify primordial stars as those with chemical signatures typical of field stars, and enriched stars as those exhibiting strong nitrogen enrichment, with corresponding carbon and oxygen depletion. We present our sample of 133 red giant branch and core-He-burning stars, 92 of which have measured masses and inferred age estimations from asteroseismology. Of the 20 enriched stars identified, 13 have precise asteroseismic ages, of which a maximum of 3 are old enough ($> 8$ Gyr) to plausibly originate from globular clusters. The inferred asteroseismic ages indicate that most enriched stars found in the field appear too young to have originated from GCs; however, these apparently young ages are likely the result of assuming single-star evolution, rather than accounting for binary interactions or mergers. This points to alternative enrichment and evolutionary scenarios, such as mass transfer or coalescence, rather than a globular-cluster origin for most field nitrogen-rich stars.
title Not all nitrogen-rich field stars originate from globular clusters
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2603.02327