Preserving chemical signatures of primordial star formation in the first low-mass stars
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Author(s)
Ji, Alexander Pung
Frebel, Anna L.
Bromm, Volker
Date Issued
September 2015
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Citation
Ji, Alexander P. et al. “Preserving Chemical Signatures of Primordial Star Formation in the First Low-Mass Stars.” Monthly Notices of the Royal Astronomical Society 454, 1 (September 2015): 659–674 © The Authors
Version
Author's final manuscript
Abstract
We model early star-forming regions and their chemical enrichment by Population III (Pop III) supernovae with nucleosynthetic yields featuring high [C/Fe] ratios and pair-instability supernova (PISN) signatures. We aim to test how well these chemical abundance signatures are preserved in the gas prior to forming the first long-lived low-mass stars (or second-generation stars). Our results show that second-generation stars can retain the nucleosynthetic signature of their Pop III progenitors, even in the presence of nucleosynthetically normal Pop III core-collapse supernovae. We find that carbon-enhanced metal-poor stars are likely second-generation stars that form in minihaloes. Furthermore, it is likely that the majority of Pop III supernovae produce high [C/Fe] yields. In contrast, metals ejected by a PISN are not concentrated in the first star-forming haloes, which may explain the absence of observed PISN signatures in metal-poor stars. We also find that unique Pop III abundance signatures in the gas are quickly wiped out by the emergence of Pop II supernovae. We caution that the observed fractions of stars with Pop III signatures cannot be directly interpreted as the fraction of Pop III stars producing that signature. Such interpretations require modelling the metal enrichment process prior to the second-generation stars' formation, including results from simulations of metal mixing. The full potential of stellar archaeology can likely be reached in ultrafaint dwarf galaxies, where the simple formation history may allow for straightforward identification of second-generation stars.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1093/MNRAS/STV2052
