Angular momentum transfer in primordial discs and the rotation of the first stars

Abstract

We investigate the rotation velocity of the first stars by modelling the angular momentum transfer in the primordial accretion disc.Assessing the impact of magnetic braking, we consider the transition in angular momentum transport mode at the Alfv$\acute{\mathrm{e}}$n radius, from the dynamically dominated free-fall accretion to the magnetically dominated solid-body one.The accreting protostar at the centre of the primordial star-forming cloud rotates with close to breakup speed in the case without magnetic fields.Considering a physically-motivated model for small-scale turbulent dynamo amplification, we find that stellar rotation speed quickly declines if a large fraction of the initial turbulent energy is converted to magnetic energy ($\gtrsim 0.14$). Alternatively, if the dynamo process were inefficient, for amplification due to flux-freezing, stars would become slow rotators if the pre-galactic magnetic field strength is above a critical value, $\simeq 10^{-8.2}$G, evaluated at a scale of $n_{\mathrm{H}}=1{\mathrm{cm}}^{-3}$, which is significantly higher than plausible cosmological seed values ($\sim 10^{-15}$G). Because of the rapid decline of the stellar rotational speed over a narrow range in model parameters, the first stars encounter a bimodal fate: rapid rotation at almost the breakup level, or the near absence of any rotation.

10 pages, 7 figures, accepted to MNRAS

References in corpus (14)

• Theory of Star Formation
• Nucleosynthetic signatures of the first stars
• The Magnetic Fields of Classical T Tauri Stars
• The Mass Spectrum of the First Stars
• A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence
• The Formation of the First Stars II. Radiative Feedback Processes and Implications for the Initial Mass Function
• Effects of rotation on the evolution of primordial stars
• The Turbulent Origin of Spin-Orbit Misalignment in Planetary Systems
• The Biermann Battery in Cosmological MHD Simulations of Population III Star Formation
• Formation and survival of Population III stellar systems
• Gamma-ray burst progenitors
• On the Rotation of Supermassive Stars
• On the First Generation of Stars
• A Single Progenitor Model for GW150914 and GW170104

Cited by in corpus (22)

• Assembly of supermassive black hole seeds
• Conditions for detecting lensed Population III galaxies in blind surveys with the James Webb Space Telescope, the Roman Space Telescope and Euclid
• Stellar winds and metal enrichment from fast-rotating Population III stars
• Probing the initial mass function of the first stars with transients
• Rapidly rotating Population III stellar models as a source of primary nitrogen
• Exponentially amplified magnetic field eliminates disk fragmentation around the Population III protostar
• Searches for Population III pair-instability supernovae: Predictions for ULTIMATE-Subaru and WFIRST
• Impact of magnetic fields on Population III star formation
• Ionization degree and magnetic diffusivity in the primordial star-forming clouds
• Inferring the velocity of early massive stars from the abundances of extremely metal-poor stars
• Supermassive Star Formation in Magnetized Atomic-Cooling Gas Clouds: Enhanced Accretion, Intermittent Fragmentation, and Continuous Mergers
• Signatures of Rapidly Rotating Stars with Chemically Homogeneous Evolution in the First Galaxies
• Discrimination of heavy elements originating from Pop III stars in z = 3 intergalactic medium
• Shape and Spin of Minihaloes: From Large Scales to the Centres
• Rotating Supermassive Pop III Stars On The Main Sequence
• Magnetic fields limit the mass of Population III stars even before the onset of protostellar radiation feedback
• Population III star formation in the presence of turbulence, magnetic fields and ionizing radiation feedback
• Large Scale Dynamo in a Primordial Accretion Flow -- An Interpretation from Hydrodynamic Simulation
• Effects of chemically homogeneous evolution of the first stars on the 21-cm signal and reionization
• Simulating the collapse of rotating primordial gas clouds to study the survival possibility of Pop III protostars
• Ultraviolet photon production rates of the first stars: Impact on the He II $\lambda$ 1640 Å emission line from primordial star clusters and the 21-cm signal from cosmic dawn
• Direct N-body simulations of rotating and extremely massive Population III star clusters