SMA Spots Giant Star Cluster Forming Behind Dusty Fog

It may be one of the best-kept secrets in our galaxy. The Smithsonian's Submillimeter Array (SMA) has now peered through a cloud of dusty fog in order to provide the first-ever clear view of W49A, a giant star-forming region. The new image reveals a bit more about this stellar nursery, which shines 100 times brighter than the Orion nebula but is so obscured by dust that very little visible or infrared light escapes.

"We were amazed by all the features we saw in the SMA images," said Roberto Galvan-Madrid, one of the researchers, in a news release.

W49A itself is located about 36,000 light-years from Earth on the opposite side of the Milky Way. It actually represents a type of vigorous star formation of the sort seen in starburst galaxies. That's where stars form about 100 times faster than in our own galaxy.

At the heart of W49A is a giant and yet surprisingly compact star cluster. About 100,000 stars are packed into a space only 10 light-years wide 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 will almost be as crowded as a globular cluster.

What was more interesting was the detail that the new image provides. The scientists spotted an intricate network of filaments feeding gas into the center, much like tributaries feed water into rivers on Earth. The gaseous filaments in W49A form three big streamers which funnel star-building material inward at speeds up about 4,500 miles per hour. In addition, the compactness of the star cluster will allow it to remain intact for billions of years.

"We suspect that the organized architecture seen in W49A is rather common in massive stellar cluster-formation," said Hauyu Baobab, one of the researchers, in a news release.

The findings reveal a bit more about this particular region of massive star formation. In addition, it shows that as instruments improve, we're learning more and more about our universe.

The findings are published in the Astrophysical Journal.