Two-Stage Fragmentation for Cluster Formation: Analytical Model and Observational Considerations

Abstract

Linear analysis of the formation of protostellar cores in planar magnetic interstellar clouds shows that molecular clouds exhibit a preferred length scale for collapse that depends on the mass-to-flux ratio and neutral-ion collision time within the cloud. We extend this linear analysis to the context of clustered star formation. By combining the results of the linear analysis with a realistic ionization profile for the cloud, we find that a molecular cloud may evolve through two fragmentation events in the evolution toward the formation of stars. Our model suggests that the initial fragmentation into clumps occurs for a transcritical cloud on parsec scales while the second fragmentation can occur for transcritical and supercritical cores on subparsec scales. Comparison of our results with several star forming regions (Perseus, Taurus, Pipe Nebula) shows support for a two-stage fragmentation model.

arXiv comment15 pages, 6 figures, 7 tables. Accepted for publication in ApJ

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Cited by in corpus (13)

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• Does the magnetic field suppress fragmentation in massive dense cores?
• The Dynamical State of The Serpens South Filamentary Infrared Dark Cloud
• A Mathematical Model for an Hourglass Magnetic Field
• Not so different after all: Properties and Spatial Structure of Column Density Peaks in the Pipe and Orion A Clouds
• Ambipolar diffusion regulated collapse of filaments threaded by perpendicular magnetic fields
• Kinematics in Partially Ionised Molecular Clouds: Implications for the Transition to Coherence
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• Linear Stability Analysis of a Magnetic Rotating Disk with Ohmic Dissipation and Ambipolar Diffusion
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• Ionisation in Turbulent Magnetic Molecular Clouds I. Effect on Density and Mass-to-Flux Ratio Structures