Star formation within globular clusters:discrete multiple bursts and top-light mass functions

Abstract

The observed discrete multiple stellar populations and internal abundance spreads in r- and s-process elements within globular clusters (GCs) have been suggested to be explained self-consistently by discrete star formation events over a longer timescale (10^8 yr). We here investigate whether such star formation is really possible within GCs using numerical simulations that include effects of dynamical interaction between individual stars and the accumulated gas ("star-gas interaction") on star formation. The principal results are as follows. Small gas clouds with densities larger than $10^{10}$ atoms cm^{-3} corresponding to first stellar cores can be developed from gas without turbulence. Consequently, new stars can be formed from the gas with high star formation efficiencies (>0.5) in a bursty manner. However, star formation can be suppressed when the gas mass fractions within GCs (f_g) are less than a threshold value (f_g, th). This f_g, th is larger for GCs with lower masses and larger gas disks. Star-gas interaction and gravitational potentials of GCs can combine to suppress the formation of massive stars (i.e., "top-light" stellar initial mass function). Formation of He-rich stars directly from gas of massive AGB stars is possible in massive GCs due to low f_g, th (<0.01). Short bursty star formation only for f_g>f_g, th can be partly responsible for discrete multiple star formation events within GCs.

Now published in MNRAS, 19 pages, 12 figures

References in corpus (21)

• Formation and Dynamical Evolution of Multiple Stellar Generations in Globular Clusters
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• On the self-enrichment scenario of galactic globular clusters: Constraints on the IMF
• Before the first supernova: combined effects of HII regions and winds on molecular clouds
• Iron and neutron-capture element abundance variations in the globular cluster M2 (NGC 7089)
• Numerical requirements for simulations of self gravitating and non-self gravitating disks
• Extended Main Sequence Turnoffs in Intermediate-Age Star Clusters: A Correlation Between Turnoff Width and Early Escape Velocity
• Origin of Abundance Inhomogeneity in Globular Clusters
• Dust-regulated galaxy formation and evolution:A new chemodynamical model with live dust particles
• Constraining globular cluster formation through studies of young massive clusters - II. A Single Stellar Population Young Massive Cluster in NGC 34
• Primordial r-process Dispersion in Metal-Poor Globular Clusters
• Accretion of pristine gas and dilution during the formation of multiple-population globular clusters
• Globular Cluster Formation at High Density: A model for Elemental Enrichment with Fast Recycling of Massive-Star Debris
• On the origin of double main-sequence turn-offs in star clusters of the Magellanic Clouds
• Three discrete groups with homogeneous chemistry along the red giant branch in the globular cluster NGC 2808
• Rapidly rotating second-generation progenitors for the blue hook stars of ω Cen
• The origin of discrete multiple stellar populations in globular clusters
• Globular cluster formation with multiple stellar populations: self-enrichment in fractal massive molecular clouds
• Massive stars and globular cluster formation
• Formation of globular clusters with internal abundance spreads in r-process elements: strong evidence for prolonged star formation
• A discovery of young stellar objects in older clusters of the Large Magellanic Cloud