Disc fragmentation and oligarchic growth of protostellar systems in low-metallicity gas clouds

Abstract

We study low-metallicity star formation with a set of high-resolution hydrodynamics simulations for various gas metallicities over a wide range $0$--$10^{-3}{\mathrm{Z}}_{⨀}$. Our simulations follow non-equilibrium chemistry and radiative cooling by adopting realistic elemental abundance and dust size distribution. We examine the condition for the fragmentation of collapsing clouds (cloud fragmentation; CF) and of accretion discs (disc fragmentation; DF). We find that CF is suppressed due to rapid gas heating accompanied with molecular hydrogen formation even with efficient dust cooling for metallicities $\gtrsim 10^{-5}{\mathrm{Z}}_{⨀}$. Instead, DF occurs in almost all runs regardless of metallicity. We also find that, in the accretion discs, the growth of the protostellar systems is overall oligarchic. The primary protostar grows through the accretion of gas, and secondary protostars form through the interaction of spiral arms or the break-up of a rapidly rotating protostar. Despite vigorous fragmentation, a large fraction of secondary protostars are destroyed through mergers or tidal disruption events. For a few hundred years after the first adiabatic core formation, only several protostars survive in the disc, and the total mass of protostars is $0.52$--$3.8{\mathrm{M}}_{⨀}$.

arXiv comment29 pages, 24 figures, 4 tables, accepted for publication in MNRAS

References in corpus (62)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• The chemical composition of the Sun
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• The cosmological simulation code GADGET-2
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Simulations of Early Structure Formation: Primordial Gas Clouds
• One Hundred First Stars : Protostellar Evolution and the Final Masses
• Nucleosynthesis of Zinc and Iron-Peak Elements in Pop III Type II Supernovae : Comparison with abundances of Very Metal-Poor Halo Stars
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• Thermal and Fragmentation Properties of Star-forming Clouds in Low-metallicity Environments
• Formation of Primordial Stars in a LCDM Universe
• Dust in the Early Universe: Dust Formation in the Ejecta of Population III Supernovae
• First-generation black-hole-forming supernovae and the metal abundance pattern of a very iron-poor star
• Dust Formation and Survival in Supernova Ejecta
• The Formation and Fragmentation of Disks around Primordial Protostars
• Grackle: a Chemistry and Cooling Library for Astrophysics
• Protostellar Collapse with Various Metallicities
• The Mass Spectrum of the First Stars
• Radiation Hydrodynamical Evolution of Primordial H II Regions
• Evolution of Dust in Primordial Supernova Remnants: Can Dust Grains Formed in the Ejecta Survive and be Injected into the Early Interstellar Medium?
• The Structure and Evolution of Early Cosmological HII Regions
• Low-Mass Relics of Early Star Formation
• The First Stars: Mass Growth Under Protostellar Feedback
• Formation of Massive Primordial Stars: Intermittent UV Feedback with Episodic Mass Accretion
• The Destruction of Cosmological Minihalos by Primordial Supernovae
• Observational Constraints on First-Star Nucleosynthesis. I. Evidence for Multiple Progenitors of CEMP-no Stars
• The first generation of stars: first steps towards chemical evolution of galaxies
• The First Population II Stars Formed in Externally Enriched Mini-halos
• The Initial mass function of the first stars inferred from extremely metal-poor stars
• The Birth of a Massive First-Star Binary
• Descendants of the first stars: the distinct chemical signature of second generation stars
• Low-Metallicity Star Formation : Prestellar Collapse and Protostellar Accretion in the Spherical Symmetry
• Formation and survival of Population III stellar systems
• The effect of dust cooling on low-metallicity star-forming clouds
• Formation sites of Population III star formation: The effects of different levels of rotation and turbulence on the fragmentation behavior of primordial gas
• Merge or survive: Number of Population III stars per minihalo
• Binarity among CEMP-no stars: an indication of multiple formation pathways?
• Dust-cooling--induced Fragmentation of Low-metallicity Clouds
• Galactic Archeology with the AEGIS Survey: The Evolution of Carbon and Iron in the Galactic Halo
• A revised condition for self-gravitational fragmentation of protoplanetary disks
• Seeding the Second Star: enrichment from population III, dust evolution, and cloud collapse
• Gravitational instability in protostellar disks at low metallicities
• Gravitational collapse and the thermal evolution of low-metallicity gas clouds in the early Universe
• Supernova dust formation and the grain growth in the early universe: The critical metallicity for low-mass star formation
• An Ultra Metal-poor Star Near the Hydrogen-burning Limit
• Accretion Phase of Star Formation in Clouds with Different Metallicities
• Stability of Dynamically Collapsing Gas Sphere
• Spectroscopic Validation of Low-Metallicity Stars from RAVE
• Global Nonradial Instabilities of Dynamically Collapsing Gas Spheres
• Formation of the First Low-Mass Stars from Cosmological Initial Conditions
• Spiral-arm instability: giant clump formation via fragmentation of a galactic spiral arm
• Forming Pop III binaries in self-gravitating disks: how to keep the orbital angular momentum
• Physical Mechanism for the Intermediate Characteristic Stellar Mass in the Extremely Metal-poor Environments
• Formation of massive stars under protostellar radiation feedback: Very metal-poor stars
• Dust coagulation in star formation with different metallicities
• Particle splitting in smoothed particle hydrodynamics based on Voronoi diagram
• Amplification of turbulence in contracting prestellar cores in primordial minihalos
• Seeding the second star -- II. CEMP star formation enriched from faint supernovae
• Can the Growth of Dust Grains in Low-Metallicity Star-Forming Clouds Affect the Formation of Metal-Poor Low-Mass Stars?
• Spiral arm instability -- III. Fragmentation of primordial protostellar discs
• Fates of the dense cores formed by fragmentation of filaments: do they fragment again or not?
• Fragmentation in a Primordial Accretion Flow

Cited by in corpus (5)

• Dynamical evolution of Population III stellar systems and the resulting binary statistics
• Gravitational waves from the remnants of the first stars in nuclear star clusters
• Gravitational Fragmentation of Extremely Metal-poor Circumstellar Discs
• Coronal Properties of Low-mass Population III Stars and the Radiative Feedback in the Early Universe
• When did the initial mass function become bottom-heavy?