Looking into the hearts of Bok globules: MM and submm continuum images of isolated star-forming cores

TL;DR

This study investigates the physical properties and evolutionary stages of star-forming cores in 32 Bok globules using infrared, submillimetre, and millimetre continuum observations, revealing diverse stages and evidence of multiple star formation.

Contribution

It provides a comprehensive analysis of isolated low-mass star-forming cores, combining multi-wavelength data to classify evolutionary stages and assess star formation processes in Bok globules.

Findings

Submm emission detected in 26 of 32 cores

Identified 9 starless cores, 9 Class 0, and 12 Class I YSOs

Most globules show evidence of forming multiple stars with different stages

Abstract

We present the results of a comprehensive infrared, submillimetre, and millimetre continuum emission study of isolated low-mass star-forming cores in 32 Bok globules, with the aim to investigate the process of star formation in these regions. The submillimetre and millimetre dust continuum emission maps together with the spectral energy distributions are used to model and derive the physical properties of the star-forming cores, such as luminosities, sizes, masses, densities, etc. Comparisons with ground-based near-infrared and space-based mid and far-infrared images from Spitzer are used to reveal the stellar content of the Bok globules, association of embedded young stellar objects with the submm dust cores, and the evolutionary stages of the individual sources. Submm dust continuum emission was detected in 26 out of the 32 globule cores observed. For 18 globules with detected (sub)mm cores we derive evolutionary stages and physical parameters of the embedded sources. We identify nine starless cores, most of which are presumably prestellar, nine Class 0 protostars, and twelve Class I YSOs. Specific source properties like bolometric temperature, core size, and central densities are discussed as function of evolutionary stage. We find that at least two thirds (16 out of 24) of the star-forming globules studied here show evidence of forming multiple stars on scales between 1,000 and 50,000 AU. However, we also find that most of these small prototstar and star groups are comprised of sources with different evolutionary stages, suggesting a picture of slow and sequential star formation in isolated globules