The Arches Cluster is the densest known star cluster in the Milky Way, and is located about 100 light years distant, in the constellation Sagittarius. Due to extremely heavy optical extinction by dust in this region, the cluster is obscured in the visual bands, and is observed in the X-ray, infrared, and radio bands. It contains about 150 young, very hot stars that are many times larger and more massive than our Sun.The cluster also contains hot gas, produced in shocks by collisions among the massive, high-velocity stellar winds flowing outwards from the stars.
This star cluster and the Quintuplet cluster, another massive young cluster in the region, are estimated to be two to four million years old. The most massive of their stars are expected to become supernovas, forming neutron stars or black holes, or else be torn apart by tidal forces from SagA*, the supermassive black hole known to lie at the Galactic center.