The birthplace of stars can be a beautiful thing. For evidence of this you need to look no further than the above image of the Prawn Nebula. It was taken by the MPG/ESO 2.2 metre telescope in Chile.
A nebula is a large interstellar cloud composed primarily of hydrogen and helium. There are a few processes through which a nebula can form. One is by the gravitational attraction of matter. Another is in a supernova event when a massive star dies and explodes releasing its raw materials into the surrounding space. Nebulae are commonly referred to as ‘stellar nurseries’ because they are the birthplace of stars. When the mass and pressure inside a nebula reach a certain point, nuclear fusion begins and the first stage of star formation commences. This is what we are seeing in this picture of the Prawn Nebula.
The photograph is dominated by several young, bright blue stars glowing in ultraviolet light, which is not visible to human eyes. These are very large O type stars that live fast and die young. They generally only last about a million years before they go supernova. After their death, the material they release into space is recycled into new stars.
Also seen are several dark patches. These aren’t gaps in the nebula but clouds of dust between the nebula and us. These clouds absorb the light the nebula is releasing and there are probably several more young stars behind them. The bright colours in the background are caused by glowing gases. The red colour seen is from ionized hydrogen while the blue is oxygen. The light from the newly formed stars is what causes these clouds of hydrogen and oxygen gas to glow.
The Prawn Nebula is better known as Gum 56 named after astronomer Colin Stanley Gum who studied the H II regions of galaxies. H II regions are places where new star formation has recently occurred or is occurring. The Prawn Nebula is classified as an H II region because of the recent birth of several large stars.
Most of the stars seen in the picture are actually foreground or background stars and aren’t present in the nebula.
The Prawn Nebula is about 6,000 light-years from Earth so we are seeing these young stars the way they were 6000 years ago. The nebula is about 250 light-years across. Despite being quite large, it is fairly faint and most of the radiation it releases is in parts of the spectrum we humans cannot see so optical telescopes aren’t very useful for observing it.
This is by far the most detailed image of the Prawn Nebula ever taken.