The origin of low [alpha/Fe] ratios in extremely metal-poor stars
View/ Open
Author
Kobayashi, Chiaki
Ishigaki, Miho N.
Tominaga, Nozomu
Nomoto, Ken'ichi
Attention
2299/19373
Abstract
We show that the low ratios of $\alpha$ 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., $13-25M_\odot$ 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 [$\alpha$/Fe] of carbon enhanced metal-poor stars can also be reproduced with $13-25M_\odot$ 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.