Credit: J. F. Albacete Colombo, M. Méndez, & N. I. Morrell, 2003,
Monthly Notices of the Royal Astronomical Society, vol. 346, pg. 704.
Carina in Color
Nature uses color to convey information. Our eyes contain detectors called cones which are sensitive to different wavelengths of light; the cones pass signals to our brain which the brain interprets as color, so that we can distinguish red from blue from green from "atomic tangerine". Most objects we see are colored because they reflect certain wavelengths of light better than others; other objects are colored because they emit certain wavelengths more than others. Such colored emission usually indicates how hot an object is. Since X-rays are (usually) not reflected, X-ray colors can indicate how hot or energetic the emitting object is. The image above (taken by the XMM-Newton X-ray Observatory) is an X-ray color image of the Carina Nebula, a famous star-forming region in the Milky Way. In this image red indicates low-energy X-ray emission, green medium energy emission and blue high energy emission. Blue objects have more high energy emission than low energy emission, because they either produce more high energy X-ray photons, or because their low-energy X-ray photons cannot penetrate the material between us and the star. The X-ray sources are stars of various masses and ages. The brightest, blue-white object in the middle of the field is Eta Carinae, one of the Galaxy's more massive and violent stars.
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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:27:16 EDT