Low-mass star formation triggered by early supernova explosions

Gen Chiaki, Naoki Yoshida, Tetsu Kitayama

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

We study the formation of low-mass and extremely metal-poor stars in the early universe. Our study is motivated by the recent discovery of a low-mass (M* ≤ 0.8 M) and extremely metal-poor (Z ≤ 4.5 × 10-5 Z) star in the Galactic halo by Caffau et al. We propose a model that early supernova (SN) explosions trigger the formation of low-mass stars via shell fragmentation. We first perform one-dimensional hydrodynamic simulations of the evolution of an early SN remnant. We show that the shocked shell undergoes efficient radiative cooling and then becomes gravitationally unstable to fragment and collapse in about a million years. We then follow the thermal evolution of the collapsing fragments using a one-zone code. Our one-zone calculation treats chemistry and radiative cooling self-consistently in low-metallicity gas. The collapsing gas cloud evolves roughly isothermally, until it cools rapidly by dust continuum emission at the density 1013-1014 cm-3. The cloud core then becomes unstable and fragments again. We argue that early SNe can trigger the formation of low-mass stars in the extremely metal-poor environment as Caffau et al. discovered recently.

Original languageEnglish
Article number50
JournalAstrophysical Journal
Volume762
Issue number1
DOIs
Publication statusPublished - 2013 Jan 1
Externally publishedYes

Keywords

  • stars: formation
  • supernovae: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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