Herschel image of IC 5146
This colour-composite image of IC 5146 shows the extended filamentary structure of this star-forming cloud. A detailed study of this complex has shown a total of 27 filaments that all appear to have very similar widths, with a value of about 0.3 light years.
Over 350 compact starless cores have been detected embedded in the filaments in this region: about 45 of these are gravitationally bound, pre-stellar core candidates, the seeds of future stars. All pre-stellar cores are located in the densest, unstable filaments of the cloud - mostly along the main filamentary streamer visible in the central part of the image.
The glowing cavity on the left side of the image, also known as the Cocoon Nebula, is an HII region, where a young and bright B0 star illuminates the ionised hydrogen gas, causing it to shine. Some young stellar objects are visible as bright spots along the main filaments; many other young stellar objects are located in the Cocoon Nebula but are not visible in this image.
Located at a distance of about 1500 light years, the IC 5146 complex belongs to the Gould Belt, a giant ring of stars and star-forming clouds in the vicinity of the Sun.
This image is based on observations performed by SPIRE at 500 and 250 μm and by PACS at 70 μm. These observations of IC 5146 are part of an extensive survey of the Gould Belt currently undertaken with Herschel.