A Highly Reddened Star Cluster Embedded in the Galactic Plane

We found a cluster of early-type star candidates embedded in the Galactic plane by using optical to near-infrared broadband imaging. The observed region is around the 10 highly reddened stars found as a possible new and very remote open cluster by Stephenson. The 10 stars are identified as red supergiants, and several similar stars are newly found in our images. Furthermore, 25 early-type star candidates suffering visual extinction of A_V~11.2 have been identified from various color-magnitude and color-color diagrams. These stars are likely to make a star cluster, and we estimate its age and distance to be ~10^7.7 yr and ~1.5 kpc, respectively.