The concentration of ultraviolet-bright stars suggests that they are a product of stellar collisions or mergers. Stars’ interiors are very hot compared with their outer, low-density envelopes; if the outer layers are removed, stars will emit a great deal of ultraviolet light. The stars in this image are close to each other—500 to 5,000 times the distance of Earth to the Sun—so it is likely that they collided or merged, ripping off each other’s outer layers and causing the bright ultraviolet emissions seen here.