The Evolution of Density Structure of Starless and Protostellar Cores

TL;DR

This study analyzes the density structures of nine dense cores at various evolutionary stages, revealing different power-law profiles and suggesting evolutionary links between starless and protostellar cores.

Contribution

It provides detailed near-infrared extinction measurements and models the density profiles of cores, highlighting the evolution of density structures from starless to protostellar stages.

Findings

Starless cores show two density profiles: p ~ -1.0 and p ~ -2.5.

Protostellar cores predominantly have p ~ -2.5.

Prestellar cores with p ~ -2.5 may evolve into protostellar cores.

Abstract

We present a near-infrared extinction study of nine dense cores at evolutionary stages between starless to Class I. Our results show that the density structure of all but one observed cores can be modeled with a single power law rho \propto r^p between ~ 0.2R-R of the cores. The starless cores in our sample show two different types of density structures, one follows p ~ -1.0 and the other follows p ~ -2.5, while the protostellar cores all have p ~ -2.5. The similarity between the prestellar cores with p ~ -2.5 and protostellar cores implies that those prestellar cores could be evolving towards the protostellar stage. The slope of p ~ -2.5 is steeper than that of an singular isothermal sphere, which may be interpreted with the evolutionary model of cores with finite mass.