Wild Duck Cluster Captured in Spectacular New Image from ESO

The Wide Field Imager on the MPG/ESO 2.2-meter telescope has captured a spectacular new image of one of the most star-rich open clusters currently known. Called Messier 11, or the Wild Duck Cluster, the picture reveals a host of blue stars against the backdrop of space.

Messier 11, known as NGC 6705, is an open cluster, which is sometimes referred to as a galactic cluster. It's located about 6,000 light-years away in the constellation Scutum. Open clusters are typically found lying in the arms of spiral galaxies in the denser regions of irregular galaxies and Messier 11, in particular, is one of the most star-rich and compact of the open clusters. It's almost 20 light-years across and possesses about 3,000 stars.

Open clusters are different from globular clusters, which tend to be very dense and tightly bound by gravity. Globular clusters usually contain hundreds of thousands of very old stars.

Studying open clusters is a good way to test theories of stellar evolution. The stars form from the same initial cloud of gas and dust and are therefore very similar to one another, possessing relatively the same age and chemical composition. This means that scientists can make direct comparisons between the different evolutionary stages within the same cluster.

For example, the researchers can ask whether a 10 million year old star with the same mass as the sun evolve in a different way to another star that is the same age, but half as massive. In this sense, open clusters are the closest thing that astronomers have to laboratory conditions.

Because the stars within open clusters are so loosely bound to one another, though, they're subject to the effects of gravity from neighboring celestial objects. In just a few million years, it's likely that Messier 11 will disperse and the cluster will merge with its surroundings. For now, though, it's producing some spectacular images.