Exponentially amplified magnetic field eliminates disk fragmentation around the Population III protostar

Abstract

One critical remaining issue to unclear the initial mass function of the first (Population III) stars is the final fate of secondary protostars formed in the accretion disk, specifically whether they merge or survive. We focus on the magnetic effects on the first star formation under the cosmological magnetic field. We perform a suite of ideal magnetohydrodynamic simulations until 1000 years after the first protostar formation. Instead of the sink particle technique, we employ a stiff equation of state approach to represent the magnetic field structure connecting to protostars. Ten years after the first protostar formation in the cloud initialized with $B_0=10^{-20}$ G at $n_0=10^4\mathrm{c}{\mathrm{m}}^{-3}$, the magnetic field strength around protostars amplifies from pico- to kilo-gauss, which is the same strength as the present-day star. The magnetic field rapidly winds up since the gas in the vicinity of the protostar ($\le 10$ au) has undergone several tens orbital rotations in the first decade after protostar formation. As the mass accretion progresses, the vital magnetic field region extends outward, and the magnetic braking eliminates fragmentation of the disk that would form in the unmagnetized model. On the other hand, assuming a gas cloud with small angular momentum, this amplification might not work because the rotation would be slower. However, disk fragmentation would not occur in that case. We conclude that the exponential amplification of the cosmological magnetic field strength, about $10^{-18}$ G, eliminates disk fragmentation around the Population III protostars.

arXiv comment9 pages, 5 figures, accepted for publication in ApJL

References in corpus (34)

• Reconnection in a Weakly Stochastic Field
• The Assembly of the First Massive Black Holes
• One Hundred First Stars : Protostellar Evolution and the Final Masses
• The Magnetic Fields of Classical T Tauri Stars
• Primordial Star Formation under the Influence of Far Ultraviolet Radiation: 1540 Cosmological Halos and the Stellar Mass Distribution
• A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence
• Possible Indirect Confirmation of the Existence of Pop III Massive Stars by Gravitational Wave
• Can Supermassive Black Holes Form in Metal-Enriched High-Redshift Protogalaxies ?
• Evolution of Massive Protostars via Disk Accretion
• Evolution of massive population III stars with rotation and magnetic fields
• 3D Turbulent Reconnection: Theory, Tests and Astrophysical Implications
• The generation of strong magnetic fields during the formation of the first stars
• Magnetic Fields in Population III Star Formation
• Cosmological Magnetic Field: a fossil of density perturbations in the early universe
• The Birth of a Massive First-Star Binary
• Formation and survival of Population III stellar systems
• The Formation of Population III Stars in Gas Accretion Stage: Effects of Magnetic Fields
• Merge or survive: Number of Population III stars per minihalo
• The importance of magnetic fields for the initial mass function of the first stars
• Magnetic field amplification during gravitational collapse - Influence of initial conditions on dynamo evolution and saturation
• Predicting the locations of possible long-lived low-mass first stars: Importance of satellite dwarf galaxies
• Protostellar Jets Enclosed by Low-velocity Outflows
• Magnetic Fields in the Formation of the First Stars. I. Theory vs. Simulation
• Magnetic field amplification in accretion discs around the first stars: implications for the primordial IMF
• Formation of the first star clusters and massive star binaries by fragmentation of filamentary primordial gas clouds
• Accretion Phase of Star Formation in Clouds with Different Metallicities
• Magnetic Flux Expulsion in Star Formation
• Magnetic fields in the formation of the first stars.--II Results
• Angular momentum transfer in primordial discs and the rotation of the first stars
• Magnetohydrodynamic effect on first star formation: prestellar core collapse and protostar formation
• Different Modes of Star Formation II: Gas Accretion Phase of Initially Subcritical Star-Forming Clouds
• Evolution of Magnetic Fields in Collapsing Star-forming Clouds under Different Environments
• Supermassive Star Formation in Magnetized Atomic-Cooling Gas Clouds: Enhanced Accretion, Intermittent Fragmentation, and Continuous Mergers
• First Star Formation in the Presence of Primordial Magnetic Fields

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• Magnetic braking during direct collapse black hole formation
• Merger Conditions of Population III Protostar Binaries
• Effects of chemically homogeneous evolution of the first stars on the 21-cm signal and reionization
• Halo Mergers Enhance the Growth of Massive Black Hole Seeds
• Population III star formation: multiple gas phases prevent the use of an equation of state at high densities
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