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

TL;DR

This paper presents a two-stage fragmentation model for star formation in molecular clouds, combining linear analysis with observational data, highlighting how clouds evolve through initial large-scale clump formation followed by smaller core fragmentation.

Contribution

It introduces a novel two-stage fragmentation framework for star formation, integrating analytical models with observational considerations and ionization profiles.

Findings

Initial fragmentation occurs at parsec scales in transcritical clouds.

Second fragmentation occurs at subparsec scales in transcritical and supercritical cores.

Model aligns with observations from Perseus, Taurus, and Pipe Nebula.

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.