The familiar winter sky constellation Orion takes on a spectacular guise in the infrared, as seen in this false-color image constructed from data collected by IRAS--the Infrared Astronomical Satellite. This picture, covering about 30 degrees x 24 degrees is a composite of IRAS wavelength band data centered at 12 microns, 60 microns, and 100 microns. New processing techniques have been used to enhance faint details and remove the instrumental artifacts (stripes) seen in earlier IRAS images. The warmest features, e.g.~the stars, are brightest at 12 microns. This emission is coded blue. The interstellar dust is cooler and shines brighter at 60 microns (coded green) and 100 microns (coded red).
The bright yellow region in the lower right of the picture is the Sword of Orion, containing the Great Orion Nebula (M42 and M43). Above it to the left is the nebulosity around the belt star Zeta Orionis which contains the often photographed Horsehead Nebula (barely visible as a small indentation on the right side). Higher and to the left is M78, a reflection nebula. The Rosette Nebula is the brightest object near the left margin of the picture.
Most of the visually bright stars of Orion are not prominent in the infrared. However, Betelgeuse can be easily seen in the upper center of the picture as a blue-white dot (the faint tail is an instrumental artifact). The large ring to the right of Betelgeuse is the remnant of a supernova explosion, centered around the star Lambda Orionis. These rings are quite common in the IRAS sky. Another one, fainter and larger, can be seen in the lower left quadrant of the image.
INFRARED PROCESSING AND ANALYSIS CENTER