Abundances of Sr, Y, and Zr in Metal‐Poor Stars and Implications for Chemical Evolution in the Early Galaxy

2008/07/04 by Y. -Z. Qian, Y.‐Z. Qian, G. J. Wasserburg · 4 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Chemical evolution #Galaxy #Galaxy formation and evolution #Physics #Stars #Stellar, planetary, and galactic studies #astro-ph

paper · pdf · doi:10.1086/591545

42 pages, 8 figures, to appear in ApJ

arxiv created 2008/07/04 · openalex publication_date 2008/10/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We have attributed the elements from Sr through Ag in stars of low metallicities ([Fe/H] ≾ -1.5) to charged-particle reactions (CPRs) in neutrino-driven winds, which are associated with neutron star formation in low-mass and normal supernovae (SNe) from progenitors of ~8-11 M⊙ and ~12-25 M⊙, respectively. Using this rule and attributing all Fe production to normal SNe, we previously developed a phenomenological two-component model, which predicts that [Sr/Fe] ≥ -0.32 for all metal-poor stars. This is in direct conflict with the high-resolution data now available, which show that there is a great shortfall of Sr relative to Fe in many stars with [Fe/H] ≾3. The same conflict also exists for the CPR elements Y and Zr. We show that the data require a stellar source leaving behind black holes and that hypernovae (HNe) from progenitors of ~25-50 M⊙ are the most plausible candidates. If we expand our previous model to include three components (low-mass and normal SNe and HNe), we find that essentially all of the data are very well described by the new model. The HN yield pattern for the low-A elements from Na through Zn ( including Fe) is inferred from the stars deficient in Sr, Y, and Zr. We estimate that HNe contributed ~24% of the bulk solar Fe inventory while normal SNe contributed only ~ 9% (not the usually assumed ~33%). This implies a greatly reduced role of normal SNe in the chemical evolution of the low-A elements.

Citations

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Cited by

• Explosive nucleosynthesis in core-collapse supernovae
• Chemical evolution with rotating massive star yields – I. The solar neighbourhood and the s-process elements
• Principal component analysis on chemical abundances spaces
• THE UBIQUITY OF THE RAPID NEUTRON-CAPTURE PROCESS*