The Reddest of the Red Stars by Vincent S. FosterSome stars will make you see red. These are carbon stars, a unique type of variable star, that accumulate soot in their upper atmospheres. which scatters light near the blue end of the spectrum. What remains to be seen is the red component of a star's light. As the carbon particles accumulate, the star's brightness decreases and becomes even redder. Eventually, the carbon absorbs enough radiation to escape the star, and the cycle begins again. Beginning astronomers are often disappointed because they cannot see the rainbow of colors that appears in celestial photos taken by the Hubble telescope. This is because the human eye's color sensors do not work well under low light levels. So why can we see the color of carbon stars, but not most other celestial objects? Because their light is both bright and concentrated in one point rather than being scattered like nebulae and galaxies. Point binoculars or a small telescope at a carbon star and you'll see its color even more clearly. This is because the glasses will capture much more light than your eye and will help stimulate your color receptors. Although carbon stars are the reddest of the red stars, there are varying levels of red in these stars. Astronomers determine the redness of a star by observation and simple calculations. They measure the magnitude of the star using blue (B) and visual (V) filters. Then they subtract the visual magnitude of blue. This leaves a number designated BV called the color index. The more positive the color index, the redder the star. For example, if a star has a blue magnitude of 5 and a visual magnitude of 3, then it has a color index of 2. Color indices range from approximately -0.5 for the star. the bluest stars in middle of paper......orite with a color index of 4.4, making it a visually striking red star. Its magnitude varies between 7.8 and 9.3 over 369 days. If you want to observe more carbon stars, visit the website of the Saguaro Astronomy Club in the United States, which maintains a database containing 334 red stars. Go to www.saguaroastro.org The Astronomical League of the United States also has a list of 100 carbon stars as part of its Carbon Star Observing Program. It can be downloaded from www.astroleague.org Carbon stars will delight your eyes and help you perfect your observation skills. If you keep an observational journal, you risk exhausting your thesaurus looking up different ways to say "red." One thing is certain though. Looking at those red stars won't leave you blue.ENDWord Count: 1,544Vincent S. Foster37 Brigantine Blvd.Waretown, NJ 08758USATel: 609-488-5898Email: [email protected]