Wealth of new results from AKARI infrared sky-surveyor

This composite image shows star formation revealed by AKARI’s wide-area survey in the reflection nebula IC4954/4955. The nebula is located in the constellation Vulpecula, around 6500 light years from us. The Near- and Mid-infrared Camera (IRC) and the Far-Infrared Surveyor (FIS) instruments onboard AKARI carried out observations of this region at seven different infrared wavelengths and revealed a continuing cycle of star formation over three generations, across enormous spatial scales (the actual scale of the picture is approximately 13x20 light years). Astronomers believe that these high density molecular clouds located in IC4954/4955 often participate in star formation when supernova explosions and intense radiation from young high-mass stars sweeps the interstellar material together into these high-density regions. AKARI infrared observations over the wavelength range from 9 to 160 micrometres detected the evidence of such star formation (marked by green crosses). The left panel is a three-colour composite image from AKARI’s 9 (blue), 11 (green), and 18 (red) micrometre data. The two arc-like structures visible in the panel are formed by a young-massive star (not seen in the image) at the centre of the nebula, sweeping material outward by their strong radiation pressure. The right panel is a colour-composite image from far-infrared data, showing that the arcs are also heated by the central star and appear in blue. This image also shows lower-temperature material in the nebula (seen as red); that this would normally be invisible in the optical wavelengths since interstellar material masks the light from coming from behind. These cooler regions contain large amounts of interstellar material that will eventually form a new generation of stars. Credits: JAXA