Many stars form in giant groups known as open clusters, which are crucial for the galaxy's development. There should be about 30,000 clusters in the Milky Way, but we've only ever found 2,500. Now, you can raise that number to 2,596.
The VISTA Variables telescope, an infrared telescope housed at the European Southern Observatory's Panaral Observatory in Chile, was responsible for detecting 96 new open clusters through the thick cosmic dust. It's particularly difficult finding these open clusters because they're composed of young stars about half the mass of our Sun, meaning they give off relatively little light, and they generally form in naturally dusty regions that block and absorb most of that light.
This means that it's difficult to see much evidence at all of these open cluster in the visible wavelengths that we're used to, so we have to turn to huge infrared telescopes to have much chance of seeing them. The 96 newly discovered clusters represent the single biggest discovery of such clusters ever, and the hope is that further observations of the galaxy with the infrared telescope will reveal tons more of these clusters.
Further understanding the age, composition, and structure of these previously hidden clusters will help us put into perspective the evolution of the galaxy as a whole. You can see a gorgeous mosaic of some of the newly discovered clusters up top - you'll definitely want to click on this one for a closer look.
Team member Radostin Kurtev describes the new 96 clusters:
"We found that most of the clusters are very small and only have about 10-20 stars. Compared to typical open clusters, these are very faint and compact objects — the dust in front of these clusters makes them appear 10 000 to 100 million times fainter in visible light. It's no wonder they were hidden."
The search will now focus on other dusty areas of our Milky Way where similarly small and faint clusters might be hiding. It's basically the astronomical equivalent of spring cleaning.
Via the ESO.