The Different Structures of the Two Classes of Starless Cores

TL;DR

This paper presents a model distinguishing two classes of starless cores based on their central density, revealing significant structural and behavioral differences that improve interpretation of observational data.

Contribution

The study introduces a model that differentiates starless cores into thermally super-critical and sub-critical classes based on density, enhancing understanding of their properties.

Findings

Cores with density above 10^5 cm^-3 are thermally super-critical.

Cores below this density are thermally sub-critical.

The model explains observational differences among starless cores.

Abstract

We describe a model for the thermal and dynamical equilibrium of starless cores that includes the radiative transfer of the gas and dust and simple CO chemistry. The model shows that the structure and behavior of the cores is significantly different depending on whether the central density is either above or below about 10^5 cm-3. This density is significant as the critical density for gas cooling by gas-dust collisions and also as the critical density for dynamical stability, given the typical properties of the starless cores. The starless cores thus divide into two classes that we refer to as thermally super-critical and thermally sub-critical.This two-class distinction allows an improved interpretation of the different observational data of starless cores within a single model.