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Nitrogen-rich field stars look younger than expected

Nitrogen-rich field stars have abundance patterns similar to chemically enriched stars in globular clusters (GCs) and are therefore previously thought to originate from disrupted GCs via tidal stripping or evaporation. They may not!

Upper panel: histogram of the ages estimated from asteroseismology against GC ages from Forbes & Bridges (2010) (grey histogram). Lower panel: histogram of the masses derived from asteroseismology. Diagrams are taken from Fig. 1 in the paper.

Ellen I. Leitinger and colleagues in a recent paper in Astronomy & Astrophysics reveal that GCs cannot fully account for the observed population of nitrogen-rich field stars because some stars are too young to have been originating in globular clusters. This indicates alternative enrichment and evolutionary scenarios, such as mass transfer or coalescence, rather than a globular-cluster origin for most field nitrogen-rich stars.

The paper is a collaboration between researchers in Italy, in Birmingham, UK and Karsten Brogaard from Stellar Astrophysics Centre, Aarhus University.

Title of the paper is ' Not all nitrogen-rich field stars originate from globular clusters'. It is available as

 https://doi.org/10.1051/0004-6361/202558003  

This paper also forms a part of a podcast in the series The StarXiv, episode 32 – Ancient star clusters and growing black holes to be found at starxiv.com/2026/03/16/episode-32-ancient-star-clusters-and-growing-black-holes/