The Stellar Content of the Infalling Molecular Clump G286.21+0.17

• Published in: The Astrophysical journal Vol. 850; no. 1; pp. 12 - 19
• Main Authors: Andersen, M., Barnes, P. J., Tan, J. C., Kainulainen, J., Marchi, G. de
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 20.11.2017; IOP Publishing
• Subjects: Astrophysics; Infrared imaging; ISM: clouds; ISM: individual objects (G286.21+0.17); Massive stars; Order parameters; Pre-main sequence stars; Space telescopes; Spatial distribution; Star & galaxy formation; Star clusters; Star formation; stars: formation; stars: pre-main sequence; Stellar age; Stellar evolution; Stellar mass; Temporal distribution
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.3847/1538-4357/aa9072

The early evolution during massive star cluster formation is still uncertain. Observing embedded clusters at their earliest stages of formation can provide insight into the spatial and temporal distribution of the stars and thus probe different star cluster formation models. We present near-infrared imaging of an 8′ × 13′ (5.4 pc × 8.7 pc) region around the massive infalling clump G286.21+0.17 (also known as BYF73). The stellar content across the field is determined and photometry is derived in order to obtain stellar parameters for the cluster members. We find evidence for some sub-structure (on scales less than a parsec in diameter) within the region with apparently at least three different sub-clusters associated with the molecular clump based on differences in extinction and disk fractions. At the center of the clump we identify a deeply embedded sub-cluster. Near-infrared excess is detected for 39%-44% in the two sub-clusters associated with molecular material and 27% for the exposed cluster. Using the disk excess as a proxy for age, this suggests the clusters are very young. The current total stellar mass is estimated to be at least 200 M . The molecular core hosts a rich population of pre-main-sequence stars. There is evidence for multiple events of star formation both in terms of the spatial distribution within the star-forming region and possibly from the disk frequency.