Within the central regions of Cepheus lies a network of overlapping molecular clouds. Ranging over a wide distance from some 650 to 1,500 light years from the Solar System, these clouds act as stellar nurseries. They are illuminated by the light of the newly-forming stars within them, and crossed by dark lanes of material obscuring sections of the shining nebulae behind.
The Cepheus Bubble, a spherical structure within the nebulosity of the Cepheus Molecular Cloud Complex, seen here in infrared. Around the edges of the bubble, compression of material in the clouds had resulted in the formation of several regions of star-forming activity. Imagery provided by Aladin sky atlas
In the eastern part of the complex is a broad spherical area, the site of an ancient supernova, known as the Cepheus Void. In other regions the nebulous material has been parted by radiation pressure from young stars, and a notable example of this is the Cepheus Bubble in the southwestern part of the cloud complex.
Young clusters of stars are forming throughout this wide region, and in some cases they illuminate parts of the clouds to create bright nebulae. The Iris Nebula (C4 or NGC 7023) is an example of such a nebula, as is the Ghost Nebula (Sh2-136) deep within the complex.
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