NGC 6188 and 6193
Distance: 4300 Light Years

Right Ascension: 16 : 40.5 (hours : minutes)
Declination: -48 : 47 (degrees : minutes)

text copyright Robert Gendler 2006


NGC 6193 is a remarkable young stellar cluster which represents the core of the Ara OB1 stellar association. The stars of the vast Ara OB1 association span a full square degree of southern sky. The cluster NGC 6193 is imbedded in an area cloaked by thick gas clouds and obscuring lanes of dust. The hottest stars of the cluster, two closely spaced O-type giants HD 150135 and HD 150136, (the bright stars in the image) are the illumination source of the emission nebula NGC 6188. HD 150136 is a remarkable binary system comprised of a massive O3 type and O6V type stars which are nearly in contact with each other. Colliding stellar winds from the pair may be responsible for the prodigious x-ray emission emitted from this bright stellar system.

NGC 6193 and its emission counterpart NGC 6188 are seen in projection along the edge of a molecular cloud and immense expanding bubble of neutral hydrogen gas spanning some 300 light years. Ultraviolet radiation from the O-type giants of NGC 6193 is presently eroding the eastern edge of the parent molecular cloud and may be triggering and sustaining further star formation in other regions within it.

A likely evolutionary scenario of this region began with the formation of the older cluster NGC 6167 which is currently at the center of the expanding gas bubble. Powerful winds blasted from the first supernovae of this cluster produced the expanding bubble of neutral hydrogen gas. The expanding shell subsequently plowed into the surrounding interstellar medium, triggering the formation of the Ara OB1 association and NGC 6193 along the edge of the massive bubble some 1 to 3 million years ago.