  There have been suggestions that the abundance of Extremely Metal-Poor (EMP)
stars can be reproduced by Hypernovae (HNe), not by normal supernovae (SNe).
However, recently it was also suggested that if the innermost neutron-rich or
proton-rich matter is ejected, the abundance patterns of ejected matter are
changed, and normal SNe may also reproduce the observations of EMP stars. In
this letter, we calculate explosive nucleosynthesis with various Ye and
entropy, and investigate whether normal SNe with this innermost matter, which
we call "hot-bubble" component, can reproduce the abundance of EMP stars. We
find that neutron-rich (Ye = 0.45-0.49) and proton-rich (Ye = 0.51-0.55) matter
can increase Zn/Fe and Co/Fe ratios as observed, but tend to overproduce other
Fe-peak elements. In addition to it, we find that if slightly proton-rich
matter with 0.50 <= Ye < 0.501 with s/kb ~ 15-40 is ejected as much as ~ 0.06
Msolar, even normal SNe can reproduce the abundance of EMP stars, though it
requires fine-tuning of Ye. On the other hand, HNe can more easily reproduce
the observations of EMP stars without fine-tuning. Our results imply that HNe
are the most possible origin of the abundance pattern of EMP stars.
