Primordial Mass and Density Segregation in a Young Molecular Cloud

TL;DR

This study investigates the early spatial distribution of cores in the Pipe Nebula, revealing primordial mass and density segregation likely established in initial cluster formation stages, with volume density being a key factor.

Contribution

It provides evidence that mass and density segregation are primordial features in a young molecular cloud, emphasizing the role of volume density in initial core distribution.

Findings

Mass and volume density are spatially segregated.

Segregation shows a high degree of substructure.

Volume density influences initial core distribution.

Abstract

We analyse the geometry of the Pipe Nebula, drawn by the distribution ($Q$-spatial parameter) and hierarchy ($\Lambda$ spatial segregation) of column density peaks previously detected and catalogued. By analysing the mass and volume density of the cores, we determine that both variables shown to be spatially segregated and with a high degree of substructure. Given the early evolutionary state of the Pipe Nebula, our results suggest that both, mass and volume-density segregations, may be primordial, in the sense of appearing in the early phases of the chain of physical mechanisms which conform the cluster-formation process. We also propose that volume density, and not mass, is the parameter that most clearly determines the initial spatial distribution of pre-stellar cores.