Massive first star binaries as new tools for Galactic archaeology

¹ Department of Liberal Arts, Tokyo University of Technology, Tokyo 144-8535, Japan
² Department of Planetology, Graduate School of Science, Kobe University, Hyogo 657-8501, Japan
³ Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes of Advanced Study, Tokyo 277-8583, Japan
⁴ Kapteyn Astronomical Institute, University of Groningen, 9747AD Groningen, the Netherlands
⁵ Research Center for the Early Universe, The University of Tokyo, Tokyo 113-0033, Japan

^* e-mail: sudatkm@stf.teu.ac.jp

Published online: 24 February 2022

Abstract

Binary systems are important probes of the origin of stars with peculiar chemical features through the interactions between two stars. We have studied the evolution of a metal-free massive binary after the collision of the supernova ejecta with a low-mass companion. Theoretical models are developed using simulations of binaries after core-collapse supernovae using stellar evolution models, supernova ejecta models, and hydrodynamic simulations of the system consisting of supernova ejecta and companion stars. We find that these first star survivors will be observed as metal-rich halo stars in our Galaxy. In combination with the theoretical research, we looked for observational counterparts in the Galactic halo using the observational database where elemental abundances and kinematic data are available. We have also searched for the progenitor binary systems based on radial velocity monitoring. We report the current status of the search for massive binaries in the solar vicinity. The proposed scenario demands a new channel of star formation in the early universe and is a supplementary scenario for the origin of the known metal-poor stars.