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

(abridged) Fast stellar rotation is currently the most promising mechanismfor producing primary nitrogen in metal-poor massive stars. Chemical evolutionmodels computed with the inclusion of the yields of fast rotating models at ametallicity $Z=10^{-8}$ can account for the high N/O abundances observed innormal metal-poor halo stars. If, as believed, intermediate mass stars did nothave enough time to contribute to the interstellar medium enrichment at suchlow metallicities, the above result constitutes a strong case for the existenceof fast rotators in the primordial Universe. An important result of stellarmodels of fast rotators is that large quantities of primary 13C are produced.Hence, our goal is to investigate the consequence of fast rotation on theevolution of the 12C/13C ratio in the interstellar medium at low metallicity.We predict that, if fast rotating massive stars were common phenomena in theearly Universe, the primordial interstellar medium of galaxies with a starformation history similar to the one inferred for our galactic halo should have12C/13C ratios between 30-300. Without fast rotators, the predicted 12C/13Cratios would be $\sim$ 4500 at [Fe/H]=-3.5, increasing to $\sim$ 31000 ataround [Fe/H]=-5.0. Current data on very metal-poor giant normal stars in thegalactic halo agree better with chemical evolution models including fastrotators. To test our predictions, challenging measurements of the 12C/13C inmore extremely metal-poor giants and turnoff stars are required.

A new imprint of fast rotators: low 12C/13C ratios in extremely metal-poor halo stars