Massive stars and globular cluster formation

Abstract

We first present chemodynamical simulations to investigate how stellar winds of massive stars influence early dynamical and chemical evolution of forming globular clusters (GCs). In our numerical models, GCs form in turbulent,high-density giant molecular clouds (GMCs), which are embedded in a massive dark matter halo at high redshifts. We show how high-density, compact stellar systems are formed from GMCs influenced both by physical processes associated with star formation and by tidal fields of their host halos. We also show that chemical pollution of GC-forming GMCs by stellar winds from massive stars can result in star-to-star abundance inhomogeneities among light elements (e.g., C, N, and O) of stars in GCs. The present model with a canonical initial mass function (IMF) also shows a C-N anticorrelation that stars with smaller [C/Fe] have larger [N/Fe] in a GC. Although these results imply that ``self-pollution'' of GC-forming GMCs by stellar winds from massive stars can cause abundance inhomogeneities of GCs, the present models with different parameters and canonical IMFs can not show N-rich stars with [N/Fe] ~ 0.8 observed in some GCs (e.g., NGC 6752). We discuss this apparent failure in the context of massive star formation preceding low-mass one within GC-forming GMCs (``bimodal star formation scenario''). We also show that although almost all stars (~97%) show normal He abundances (Y) of ~0.24 some stars later formed in GMCs can have Y as high as ~0.3 in some models. The number fraction of He-rich stars with Y >0.26 is however found to be small (~10^-3) for most models.

10 pages, 8 figures, accepted by ApJ

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• Two-Dimensional Hydrodynamic Models of Super Star Clusters with a Positive Star Formation Feedback
• On the origin of double main-sequence turn-offs in star clusters of the Magellanic Clouds
• Evolution of star cluster systems in isolated galaxies: first results from direct $N$-body simulations
• Globular cluster formation with multiple stellar populations: self-enrichment in fractal massive molecular clouds
• Dark impact and galactic star formation: Origin of the Gould belt
• Formation of N-rich field stars in the high-density building blocks of the Galactic bulge
• A model for GN-z11: top-heavy stellar initial mass functions in forming galactic nuclei and ultra-compact dwarfs
• Self-consistent simulations of star cluster formation from gas clouds under the influence of galaxy-scale tidal fields
• Formation of Massive Star Clusters by Fast HI Gas Collision
• Star formation within globular clusters:discrete multiple bursts and top-light mass functions
• Formation of the Galactic globular clusters with He-rich stars in low-mass halos virialized at high redshift
• A new formation model for omega Centauri: the crossroad of astrophysical processes