ABUNDANCE PROFILING OF EXTREMELY METAL-POOR STARS AND SUPERNOVA PROPERTIES IN THE EARLY UNIVERSE

Abstract

After the Big Bang nucleosynthesis, the first heavy element enrichment in the\nUniverse was made by a supernova (SN) explosion of a population (Pop) III star\n(Pop III SN). The abundance ratios of elements produced from Pop III SNe are\nrecorded in abundance patterns of extremely metal-poor (EMP) stars. The\nobservations of the increasing number of EMP stars have made it possible to\nstatistically constrain the explosion properties of Pop III SNe. We present Pop\nIII SN models whose nucleosynthesis yields well-reproduce individually the\nabundance patterns of 48 such metal-poor stars as [Fe/H] $\\mathrel{\\rlap{\\lower\n4pt \\hbox{$\\sim$}}\\raise 1pt \\hbox {$<$}}-3.5$. We then derive relations\nbetween the abundance ratios of EMP stars and certain explosion properties of\nPop III SNe: the higher [(C+N)/Fe] and [(C+N)/Mg] ratios correspond to the\nsmaller ejected Fe mass and the larger compact remnant mass, respectively.\nUsing these relations, the distributions of the abundance ratios of EMP stars\nare converted to those of the explosion properties of Pop III SNe. Such\ndistributions are compared with those of the explosion properties of present\nday SNe: The distribution of the ejected Fe mass of Pop III SNe has the same\npeak as that of the resent day SNe but shows an extended tail down to\n$\\sim10^{-2}-10^{-5}M_\\odot$, and the distribution of the mass of the compact\nremnant of Pop III SNe is as wide as that of the present day stellar-mass black\nholes. Our results demonstrate the importance of large samples of EMP stars\nobtained by ongoing and future EMP star surveys and subsequent high-dispersion\nspectroscopic observations in clarifying the nature of Pop III SNe in the early\nUniverse.\n