Embedded cluster
Embedded clusters are stellar clusters that are still encased in its progenitor gas and are therefore areas of active low mass and high mass star formation.
Due to the dense material that surrounds them, they are impervious to optical observation but reveal themselves in other spectra such as in the near infrared and X-rays.
In these spectra, like open stellar clusters for the optical, they may be detected as stellar enhancements above expected galactic background stellar counts.
Many embedded stellar clusters are know to exist. In the case where an embedded cluster , an named object believed to exist in its vicinity is labelled.