On the emergent System Mass Function: the contest between accretion and fragmentation

Abstract

We propose a new model for the evolution of a star cluster's System Mass Function (SMF). The model involves both turbulent fragmentation and competitive accretion. Turbulent fragmentation creates low-mass seed proto-systems (i.e. single and multiple protostars). Some of these low-mass seed proto-systems then grow by competitive accretion to produce the high-mass power-law tail of the SMF. Turbulent fragmentation is relatively inefficient, in the sense that the creation of low-mass seed proto-systems only consumes a fraction, $\sim 23\%$ (at most $\sim 50\%$), of the mass available for star formation. The remaining mass is consumed by competitive accretion. Provided the accretion rate onto a proto-system is approximately proportional to its mass ($dm/dt\propto m$), the SMF develops a power-law tail at high masses with the Salpeter slope ($\sim -2.3$). If the rate of supply of mass accelerates, the rate of proto-system formation also accelerates, as appears to be observed in many clusters. However, even if the rate of supply of mass decreases, or ceases and then resumes, the SMF evolves homologously, retaining the same overall shape, and the high-mass power-law tail simply extends to ever higher masses until the supply of gas runs out completely. The Chabrier SMF can be reproduced very accurately if the seed proto-systems have an approximately log-normal mass distribution with median mass $\sim 0.11{\mathrm{M}}_{{}_{\odot }}$ and logarithmic standard deviation ${\sigma }_{{\log }_{10}(M/{\mathrm{M}}_{\odot })}\sim 0.47$).

Accepted for publication in MNRAS. 13 pages, 4 figures, 1 appendix

References in corpus (21)

• Analytical theory for the initial mass function: CO clumps and prestellar cores
• On the Star Formation Efficiency of Turbulent Magnetized Clouds
• Star formation through gravitational collapse and competitive accretion
• ATLASGAL --- properties of a complete sample of Galactic clumps
• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• Before the first supernova: combined effects of HII regions and winds on molecular clouds
• The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline
• A SCUBA survey of Orion, the low-mass end of the core mass function
• Limiting Accretion onto Massive Stars by Fragmentation-Induced Starvation
• Gravitational fragmentation and the formation of brown dwarfs in stellar clusters
• The minimum mass for star formation, and the origin of binary brown dwarfs
• The Jeans mass and the origin of the knee in the IMF
• Driven and Decaying Turbulence Simulations of Low-Mass Star Formation: From Clumps to Cores to Protostars
• Star Formation in Self-Gravitating Turbulent Fluids
• Clump Lifetimes and the Initial Mass Function
• Bondi-Hoyle-Littleton accretion and the upper mass stellar IMF
• The star formation efficiency and its relation to variations in the initial mass function
• Simulations of star formation in Ophiuchus, II: Multiplicity
• The Accelerating Pace of Star Formation
• The apparent anti-correlation between the mass opacity of interstellar dust and the surface-density of interstellar gas

Cited by in corpus (14)

• Dynamical evolution of Population III stellar systems and the resulting binary statistics
• Dynamical Accretion Flows -- ALMAGAL: Flows along filamentary structures in high-mass star-forming clusters
• Resolved Gaia Triples
• 10,000 Resolved Triples from Gaia: Empirical Constraints on Triple Star Populations
• Variation of the low-mass end of the stellar initial mass function with redshift and metallicity
• The initial magnetic criticality of prestellar cores
• Probing the Global Dust Properties and Cluster Formation Potential of the Giant Molecular Cloud G148.24+00.41
• A stochastic and analytical model of hierarchical fragmentation: The fragmentation of gas structures into young stellar objects in the interstellar medium
• Turbulence and its connection to episodic accretion in binary YSOs
• Differences in chemical evolution between isolated and embedded prestellar cores
• The fragmentation of molecular clouds in starburst environments
• Gamma Analytical Modeling Evolution (GAME) I: The physical implications of deriving the stellar mass functions from z=0 to z=8
• The fragmentation properties of massive star-forming regions in 30Dor-10 at 2000 au resolution
• On the coupled origin of the stellar IMF and multiplicity