Herschel image of the Polaris Flare
This colour-composite image of the Polaris Flare shows the extended filamentary structure of this quiescent cloud, located at a distance of about 490 light years, and characterised by little or no current star formation activity. A detailed study of this complex has revealed more than 60 filaments, 31 of which have been measured in detail. They all appear to have very similar widths, with a value of about 0.3 light years.
More than 300 compact starless cores have been detected embedded in the filaments in this region, but hardly any of them appear to be gravitationally bound, pre-stellar core candidates, the seeds of future stars. By studying this and other regions, astronomers have inferred that interstellar filaments precede the onset of star formation in molecular clouds.
This image is based on observations performed by SPIRE at 250, 350 and 500 μm. These observations of Polaris are part of an extensive survey of nearby molecular clouds, mostly located in the Gould Belt, currently undertaken with Herschel.