High-Entropy Polar Regions Around the First Protostars

Abstract

We report on simulations of the formation of the first stars in the Universe, where we identify regions of hot atomic gas (fH2 < 10-6) at densities above 10-14 g/cc, heated to temperatures ranging between 3000 and 8000 K. Within this temperature range atomic hydrogen is unable to cool effectively. We describe the kinetic and thermal characteristics of these regions and investigate their origin. We find that these regions, while small in total mass fraction of the cloud, may be dynamically important over the accretion timescale for the central clump in the cloud, particularly as a chemical, rather than radiative, mechanism for clearing the polar regions of the accretion disk of material and terminating accretion along these directions. These inherently three-dimensional effects stress the need for multi-dimensional calculations of protostellar accretion for reliable predictions of the masses of the very first stars.

12 pages, 2 figures; accepted for publication in The Astrophysical Journal Letters

References in corpus (4)

• The Formation of Population III Binaries from Cosmological Initial Conditions
• Uncertainties in H2 and HD Chemistry and Cooling and their Role in Early Structure Formation
• The Formation of the First Stars II. Radiative Feedback Processes and Implications for the Initial Mass Function
• Population III star formation in a Lambda CDM universe, I: The effect of formation redshift and environment on protostellar accretion rate

Cited by in corpus (14)

• Simulations on a Moving Mesh: The Clustered Formation of Population III Protostars
• The Mass Spectrum of the First Stars
• Constraining the Statistics of Population III Binaries
• Magnetic Fields in Population III Star Formation
• The First Population II Stars Formed in Externally Enriched Mini-halos
• Formation of massive protostars in atomic cooling haloes
• The Growth of Black Holes from Population III Remnants in the Renaissance Simulations
• The First Stars: A Low-Mass Formation Mode
• The First Stars
• Thermal instability and multi-phase interstellar medium in the first galaxies
• Multifrequency radiation hydrodynamics simulations of H2 line emission in primordial, star-forming clouds
• Impact of an accurate modeling of primordial chemistry in high resolution studies
• Impact of magnetic fields on Population III star formation
• On the operation of the chemothermal instability in primordial star-forming clouds