Limiting Accretion onto Massive Stars by Fragmentation-Induced Starvation

Abstract

Massive stars influence their surroundings through radiation, winds, and supernova explosions far out of proportion to their small numbers. However, the physical processes that initiate and govern the birth of massive stars remain poorly understood. Two widely discussed models are monolithic collapse of molecular cloud cores and competitive accretion. To learn more about massive star formation, we perform simulations of the collapse of rotating, massive, cloud cores including radiative heating by both non-ionizing and ionizing radiation using the FLASH adaptive mesh refinement code. These simulations show fragmentation from gravitational instability in the enormously dense accretion flows required to build up massive stars. Secondary stars form rapidly in these flows and accrete mass that would have otherwise been consumed by the massive star in the center, in a process that we term fragmentation-induced starvation. This explains why massive stars are usually found as members of high-order stellar systems that themselves belong to large clusters containing stars of all masses. The radiative heating does not prevent fragmentation, but does lead to a higher Jeans mass, resulting in fewer and more massive stars than would form without the heating. This mechanism reproduces the observed relation between the total stellar mass in the cluster and the mass of the largest star. It predicts strong clumping and filamentary structure in the center of collapsing cores, as has recently been observed. We speculate that a similar mechanism will act during primordial star formation.

extended version, ApJ in press

References in corpus (31)

• Theory of Star Formation
• Cold streams in early massive hot haloes as the main mode of galaxy formation
• Cold Dark Clouds: The Initial Conditions for Star Formation
• The Hubble Ultra Deep Field
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• Modeling Collapse and Accretion in Turbulent Gas Clouds: Implementation and Comparison of Sink Particles in AMR and SPH
• Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
• Star formation through gravitational collapse and competitive accretion
• Protostar Formation in the Early Universe
• The Formation of Population III Binaries from Cosmological Initial Conditions
• Stellar Multiplicity and the IMF: Most Stars Are Single
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• The Effects of Radiative Transfer on Low-Mass Star Formation
• Magnetic processes in a collapsing dense core. I Accretion and Ejection
• The Dynamics of Radiation Pressure-Dominated HII Regions
• Circumventing the radiation pressure barrier in the formation of massive stars via disk accretion
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• Fragmentation of Massive Protostellar Disks
• 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 ?
• Resolving the Formation of Protogalaxies. I. Virialization
• Understanding Spatial and Spectral Morphologies of Ultracompact H II Regions
• Driven and Decaying Turbulence Simulations of Low-Mass Star Formation: From Clumps to Cores to Protostars
• Ionisation-induced star formation II: External irradiation of a turbulent molecular cloud
• Molecular Line Emission from Massive Protostellar Disks: Predictions for ALMA and the EVLA
• Clump Lifetimes and the Initial Mass Function
• The structure of molecular clouds and the universality of the clump mass function
• High-Resolution Infrared Imaging of Herschel 36 SE: A Showcase for the Influence of Massive Stars in Cluster Environments
• The scale-free character of the cluster mass function and the universality of the stellar IMF
• Clumpy shocks and the clump mass function
• Disks around massive young stellar objects: are they common?

Cited by in corpus (2)

• Three-dimensional simulation of massive star formation in the disk accretion scenario
• Metallicity and the Universality of the IMF