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.

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

References in corpus (7)

• Theory of Star Formation
• The relation between gas and dust in the Taurus Molecular Cloud
• The Large and Small Scale Structures of Dust in the Star-Forming Perseus Molecular Cloud
• Current Star Formation in the Perseus Molecular Cloud: Constraints from Unbiased Submillimeter and Mid-Infrared Surveys
• Optical polarimetry toward the Pipe nebula: Revealing the importance of the magnetic field
• Deep Near-Infrared Survey of the Pipe Nebula II: Data, Methods, and Dust Extinction Maps
• Nonlinear Evolution of Gravitational Fragmentation Regulated by Magnetic Fields and Ambipolar Diffusion

Cited by in corpus (13)

• IN-SYNC I: Homogeneous Stellar Parameters from High Resolution APOGEE Spectra for Thousands of Pre-main Sequence Star
• 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
• Variation of the Core Lifetime and Fragmentation Scale in Molecular Clouds as an Indication of Ambipolar Diffusion
• Linear Stability Analysis of a Magnetic Rotating Disk with Ohmic Dissipation and Ambipolar Diffusion
• Non-Ideal Magnetohydrodynamic Simulations of the Two-Stage Fragmentation Model for Cluster Formation
• The Effect of Magnetic Fields and Ambipolar Diffusion on Core Mass Functions
• The Kinematic and Chemical Properties of a Potential Core-Forming Clump: Perseus B1-E
• Ionisation in Turbulent Magnetic Molecular Clouds I. Effect on Density and Mass-to-Flux Ratio Structures