2005/05/01 by R. Hirschi, Raphael Hirschi · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astronomy and Astrophysical Research #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1017/s1743921305005922
2 pages, Conf. Proceedings: From Lithium to Uranium: Elemental Tracers of Early Cosmic Evolution, June 2005, Eds.:V. Hill, P. François and F. Primas
openalex publication_date 2005/05/01 · arxiv created 2006/01/23 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/03
Nine 20 M_\odot models were computed with metallicities ranging from solar, through Z=10-5 ([Fe/H]∼−3.1) down to Z=10-8 ([Fe/H]∼−6.1) and with initial rotational velocities between 0 and 600 km s −1 to study the impact of initial metallicity and rotational velocity (Hirschi (2005)). The very large amounts of 14 N observed (∼0.03 M [odot ] ) are only produced at Z=10-8 (PopII 1/2). The strong dependence of the 14 N yields on rotation and other parameters like the initial mass and metallicity may explain the large scatter in the observations of 14 N abundance. The metallicity trends are best reproduced by the models with υini/υc ∼ 0.75 , which is slightly above the mean observed value for OB solar metallicity stars. Indeed, in the model with υini = 600 km s −1 at Z=10-8 , the 16 O yield is reduced due to strong mixing. This allows in particular to reproduce the upturn for C/O and a slightly decreasing [C/Fe], which are observed below [Fe/H]∼−3.