The rich patchwork of gas clouds in this new image make up part of a huge stellar nursery nicknamed the Prawn Nebula (also known as Gum 56 and IC 4628). Taken using the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile, this may well be one of the best pictures ever taken of this object. It shows clumps of hot new-born stars nestled in among the clouds that make up the nebula. Credit: ESO
Deeply immersed in this huge stellar nursery are 3 clusters of hot young stars – only a few million years old – which glow brightly in UV light. It is the light from these stars that causes the nebula’s gas clouds to glow. The radiation strips electrons from atoms ie ionisation, – and when they recombine they release energy in the form of light. Each chemical element emits light in characteristic colours and the large clouds of hydrogen in the nebula are the cause of its rich red glow.
Gum 56 – also known as IC 4628 or by its nickname, the Prawn Nebula – is named after the Australian astronomer Colin Stanley Gum, who, in 1955, published a catalogue of H II regions. H II regions such as Gum 56 are huge, low density clouds containing a large amount of ionised H.
A large portion of the ionisation in Gum 56 is done by 2 O-type stars, hot blue-white stars, also known as blue giants because of their colour.* This type of star is rare in the Universe as the very large mass of blue giants means that they do not live for long. After only ~a million years these stars will collapse in on themselves to become supernovae, as will many of the other massive stars in the nebula.
Besides the many newborn stars in the nebula, this large region is still filled with enough dust and gas to create an even newer generation of stars. The material forming these new stars includes remains of the most massive stars from an older generation that have already ended their lives and ejected their material in violent supernova explosions. Thus the cycle of stellar life and death continues.
Gum 56 has a diameter of 250 light-yrs, 6000 light-years from Earth, constellation Scorpius, but despite its huge size it has also often been overlooked by visual observers due to its faintness, and because most of the light it emits is at wavelengths not visible to the human eye. http://www.eso.org/public/news/eso1535/
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