Abundance Profiling of Extremely Metal-Poor Stars and Supernova
  Properties in the Early Universe
  After the Big Bang nucleosynthesis, the first heavy element enrichment in the
Universe was made by a supernova (SN) explosion of a population (Pop) III star
(Pop III SN). The abundance ratios of elements produced from Pop III SNe are
recorded in abundance patterns of extremely metal-poor (EMP) stars. The
observations of the increasing number of EMP stars have made it possible to
statistically constrain the explosion properties of Pop III SNe. We present Pop
III SN models whose nucleosynthesis yields well-reproduce individually the
abundance patterns of 48 such metal-poor stars as [Fe/H] $\mathrel{\rlap{\lower
4pt \hbox{$\sim$}}\raise 1pt \hbox {$<$}}-3.5$. We then derive relations
between the abundance ratios of EMP stars and certain explosion properties of
Pop III SNe: the higher [(C+N)/Fe] and [(C+N)/Mg] ratios correspond to the
smaller ejected Fe mass and the larger compact remnant mass, respectively.
Using these relations, the distributions of the abundance ratios of EMP stars
are converted to those of the explosion properties of Pop III SNe. Such
distributions are compared with those of the explosion properties of present
day SNe: The distribution of the ejected Fe mass of Pop III SNe has the same
peak as that of the resent day SNe but shows an extended tail down to
$\sim10^{-2}-10^{-5}M_\odot$, and the distribution of the mass of the compact
remnant of Pop III SNe is as wide as that of the present day stellar-mass black
holes. Our results demonstrate the importance of large samples of EMP stars
obtained by ongoing and future EMP star surveys and subsequent high-dispersion
spectroscopic observations in clarifying the nature of Pop III SNe in the early
Universe.
