The Young Cluster NGC 6604 and the Serpens OB2 Association

NGC 6604 is a young cluster in Serpens with an age of 4-5 Myr and at a distance of about 1.7 kpc. It forms the densest part of the wider Ser OB2 association, which contains about 100 OB stars. NGC 6604 lies about 65 pc above the Galactic plane, and has attracted special interest since it has produced a thermal chimney stretching 200 pc out of the plane. The combined effect of winds and radiation from the many OB stars has produced a rim of dense molecular material in which second-generation star formation is currently taking place.