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Title: THE ORIGIN OF LOW [α/Fe] RATIOS IN EXTREMELY METAL-POOR STARS

We show that the low ratios of α elements (Mg, Si, and Ca) to Fe recently found for a small fraction of extremely metal-poor stars can be naturally explained with the nucleosynthesis yields of core-collapse supernovae, i.e., 13-25 M {sub ☉} supernovae, or hypernovae. For the case without carbon enhancement, the ejected iron mass is normal, consistent with observed light curves and spectra of nearby supernovae. On the other hand, the carbon enhancement requires much smaller iron production, and the low [α/Fe] of carbon-enhanced metal-poor stars can also be reproduced with 13-25 M {sub ☉} faint supernovae or faint hypernovae. Iron-peak element abundances, in particular Zn abundances, are important to put further constraints on the enrichment sources from galactic archaeology surveys.
Authors:
 [1] ; ; ;  [2]
  1. School of Physics, Astronomy and Mathematics, Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom)
  2. Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)
Publication Date:
OSTI Identifier:
22365918
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 785; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON; DIAGRAMS; ELEMENT ABUNDANCE; GALAXIES; GRAVITATIONAL COLLAPSE; IRON; LIMITING VALUES; MAGNESIUM; MASS; NUCLEOSYNTHESIS; SILICON; SUPERNOVAE; VISIBLE RADIATION