What's Behind These Mysterious Crimson Clouds?

The red cloud above the center of the image is RCW 106, a huge hydrogen region that hides large stars in its interior. The stars emit strongly in the ultraviolet, causing the clouds to glow and producing the peculiar shapes.

It’s important to study these clouds because they give us clues as to how the stars within form. These stars, called O-type stars, can be many dozens of times heavier than our Sun – a fact that has puzzled researchers as they don't know how they can hold onto enough gas.

The mass and short lifetimes of O-types stars make them very rare. Only one in about three million stars is an O-type, and they only last for tens of millions of years, compared to the 10 billion years the Sun will shine. 

The stars also can’t be observed directly. The dust and gas in the clouds are too thick to let the visible light of these stars through. Using other instruments, however, it is possible to observe them at longer wavelengths.  

^{ESO / VLT Survey Telescope (VST)}