Cluster 1806-20 is made up of some highly unusual stars, including at least two carbon-rich Wolf–Rayet stars (WC9d and WCL), two blue hypergiants, and a magnetar (SGR 1806-20).
Este cúmulo contiene otras estrellas supermasivas, como dos estrellas de Wolf-Rayet ricas en carbono (WC9d y WCL), dos hipergigantes azules y un magnetar (SGR 1806-20).