But­ter­fly Cluster (M6) in Scorpius

The But­ter­fly Cluster (Messi­er 6, NGC 6405) is an open cluster of stars in the south­ern con­stel­la­tion of Scorpi­us. Its name derives from the vague resemb­lance of its shape to a but­ter­fly. The cluster is estim­ated to be 94.2 mil­lion years old and lies at a dis­tance of about 1’500 light years. 120 stars, ran­ging down to visu­al mag­nitude 15.1, have been iden­ti­fied as most likely cluster mem­bers. Most of the bright stars in this cluster are hot, blue B‑type stars but the bright­est mem­ber is a K‑type orange giant star, BM Scorpii.

To cre­ate the image, Ha data have been mixed into the red chan­nel to bring out some more details of the struc­ture. North is up in the image.

[descrip­tion from wikipedia]