A portion of our Milky Way Galaxy is shown in this image constructed from nine fields of the Infrared Astronomical Satellite (IRAS) Sky Survey Atlas. This mosaic covers approximately 35 degrees on each side and shows regions of gas and dust out of which massive new stars, thousands of times brighter than the Sun are now forming. Centered on the diffuse nebula, NGC 7822, the mosaic is a composite of 12 micron (coded blue), 60 micron (coded green), and 100 micron (coded red) wavelengths. The yellow-white areas are bright in the IRAS bands, but not apparent in visual photographs because the newly formed stars are deeply embedded in gas and dust clouds that are very opaque to optical wavelengths. The visible light energy emitted by the stars is absorbed by the clouds, heating them and thereby making them bright infrared sources.
The IRAS Sky Survey Atlas (ISSA) is the latest image product to come from the reprocessing of the IRAS wavelength data. The improved calibration and destriping methods reveal low surface brightness structure not seen in other IRAS products.
INFRARED PROCESSING AND ANALYSIS CENTER