English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Anomalously high nitrogen-to-oxygen abundance ratios [N/O] are observed inglobular clusters (GCs), among the field stars of the Milky Way (MW), and evenin the gas in a $z\approx 11$ galaxy. Using data from the APOGEE Data Release17 and the Gaia Data Release 3, we present several independent lines ofevidence that most of the MW's high-[N/O] stars were born in situ in massivebound clusters during the early, pre-disk evolution of the Galaxy.Specifically, we show that distributions of metallicity [Fe/H], energy, theangular momentum $L_z$, and distance of the low-metallicity high-[N/O] starsmatch the corresponding distributions of stars of the Aurora population and ofthe in-situ GCs. We also show that the fraction of in-situ field high-[N/O]stars, $f_{\rm N/O}$, increases rapidly with decreasing metallicity. Duringepochs when metallicity evolves from $\rm [Fe/H]=-1.5$ to $\rm [Fe/H]=-0.9$,the Galaxy spins up and transitions from a turbulent Aurora state to acoherently rotating disk. This transformation is accompanied by manyqualitative changes. In particular, we show that high N/O abundances similar tothose observed in GN-z11 were common before the spin-up ($\rm [Fe/H]\lesssim-1.5$) when up to $\approx 50\%-70\%$ of the in-situ stars formed in massivebound clusters. The dramatic drop of $f_{\rm N/O}$ at $\rm [Fe/H]\gtrsim -0.9$indicates that after the disk emerges the fraction of stars forming in massivebound clusters decreases by two orders of magnitude.

Nitrogen enrichment and clustered star formation at the dawn of the Galaxy