New giant star-forming cluster found

Washington – Researchers have discovered a star-forming region that shines 100 times brighter than the Orion nebula, however, it is so obscured by dust that very little visible or infrared light escapes.

The Smithsonian’s Submillimeter Array (SMA) has peered through the dusty fog to provide the first clear view of this stellar nursery W49A. The SMA revealed an active site of star formation being fed by streamers of infalling gas.

W49A is located about 36,000 light-years from Earth, on the opposite side of the Milky Way. It represents a nearby example of the sort of vigorous star formation seen in so-called “starburst” galaxies, where stars form 100 times faster than in our galaxy.

The heart of W49A holds a giant yet surprisingly compact star cluster. About 100,000 stars already exist within a space only 10 light-years on a side.

In contrast, fewer than 10 stars lie within 10 light-years of our Sun. In a few million years, the giant star cluster in W49A will be almost as crowded as a globular cluster.

The SMA also revealed an intricate network of filaments feeding gas into the center, much like tributaries feed water into mighty rivers on Earth. The gaseous filaments in W49A form three big streamers, which funnel star-building material inward at speeds of about 4,500 miles per hour (2 km/sec).

Being denser than average will help the W49A star cluster to survive. Most star clusters in the galactic disk dissolve rapidly, their stars migrating away from each other under the influence of gravitational tides. This is why none of the Sun’s sibling stars remain nearby. Since it is so compact, the cluster in W49A might remain intact for billions of years.

Their research has been published in the Astrophysical Journal.