The influence of magnetic fields on the thermodynamics of primordial star formation

Abstract

We explore the effects of magnetic energy dissipation on the formation of the first stars. For this purpose, we follow the evolution of primordial chemistry in the presence of magnetic fields in the post-recombination universe until the formation of the first virialized halos. From the point of virialization, we follow the protostellar collapse up to densities of $\sim 10^{12}$ cm${}^{-3}$ in a one-zone model. In the intergalactic medium (IGM), comoving field strengths of $\gtrsim 0.1$ nG lead to Jeans masses of $10^8{M}_{\odot }$ or more and thus delay gravitational collapse in the first halos until they are sufficiently massive. During protostellar collapse, we find that the temperature minimum at densities of $\sim 10^3$ cm${}^{-3}$ does not change significantly, such that the characteristic mass scale for fragmentation is not affected. However, we find a significant temperature increase at higher densities for comoving field strengths of $\gtrsim 0.1$ nG. This may delay gravitational collapse, in particular at densities of $\sim 10^9$ cm${}^{-3}$, where the proton abundance drops rapidly and the main contribution to the ambipolar diffusion resistivity is due to collisions with Li${}^{+}$. After the formation of the protostar, the increased gas temperatures may enhance the protostellar accretion rate. Our model confirms that initial weak magnetic fields may be amplified considerably during gravitational collapse and become dynamically relevant. For instance, a comoving field strength above $10^{-5}$ nG will be amplified above the critical value for the onset of jets which can magnetize the IGM.

17 pages, 12 figures, minor clarifications, accepted at ApJ

References in corpus (29)

• On the Origin of Cosmic Magnetic Fields
• Protostar Formation in the Early Universe
• Strong magnetic fields in normal galaxies at high redshifts
• Magnetic processes in a collapsing dense core. I Accretion and Ejection
• A galaxy at a redshift z = 6.96
• Can Supermassive Black Holes Form in Metal-Enriched High-Redshift Protogalaxies ?
• Population III stars: hidden or disappeared ?
• The First Galaxies: Assembly, Cooling and the Onset of Turbulence
• Early Cosmological HII/HeIII Regions and Their Impact on Second-Generation Star Formation
• Star formation at very low metallicity. I: Chemistry and cooling at low densities
• Magnetic processes in a collapsing dense core. II Fragmentation. Is there a fragmentation crisis ?
• The effect of magnetic fields on star cluster formation
• How well do we understand cosmological recombination?
• The Biermann Battery in Cosmological MHD Simulations of Population III Star Formation
• Formation of Massive Primordial Stars in a Reionized Gas
• Is H3+ cooling ever important in primordial gas?
• Rapid Evolution in the Most Luminous Galaxies During the First 900 Million Years
• Three-fluid plasmas in star formation II. Momentum transfer rate coefficients
• HD and H2 formation in low-metallicity dusty gas clouds at high redshift
• Reionization - A probe for the stellar population and the physics of the early universe
• Effects of primordial chemistry on the cosmic microwave background
• The First Jet in the Universe: Protostellar Jets from the First Stars
• Inflation-Produced Magnetic Fields in Nonlinear Electrodynamics
• Constraints on the Evolution of the Primordial Magnetic Field from the Small-Scale Cosmic Microwave Background Angular Anisotropy
• On the First Generation of Stars
• Three-fluid plasmas in star formation I. Magneto-hydrodynamic equations
• Primordial magnetic fields and formation of molecular hydrogen
• Galactic Dynamos and Galactic Winds
• Constraints on the Primordial Magnetic Field from ${\sigma }_8$

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• Constraints on primordial magnetic fields from magnetically-induced perturbations: current status and future perspectives with LiteBIRD and future ground based experiments
• Constraints on Primordial Magnetic Fields from their impact on the ionization history with Planck 2018
• Magnetohydrodynamic effect on first star formation: prestellar core collapse and protostar formation
• Amplification of turbulence in contracting prestellar cores in primordial minihalos
• Effects of turbulence and rotation on protostar formation as a precursor to seed black holes
• Impact of magnetic fields on Population III star formation
• Ionization degree and magnetic diffusivity in the primordial star-forming clouds
• Non-ideal magnetohydrodynamic simulations of the first star formation: the effect of ambipolar diffusion
• LiteBIRD Science Goals and Forecasts: Primordial Magnetic Fields
• Cosmological magnetic braking and the formation of high-redshift, super-massive black holes
• Amplification of Magnetic Fields in a Primordial HII Region and Supernova
• Population III star formation in the presence of turbulence, magnetic fields and ionizing radiation feedback
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• The Dawn of Black Holes
• Population III star formation: multiple gas phases prevent the use of an equation of state at high densities
• HI absorption from the epoch of reionization and primordial magnetic fields
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