AS102 Final: Stellar luminosities are often recorded by comparison with the Sun
Document Summary
Stellar luminosities are often recorded by comparison with the. For instance, the star nearest to our solar system, proxima centauri (in the alpha centauri system mentioned above), has a luminosity of . 0006 lsun, where lsun is the sun"s luminosity which is 3. 8 x 1026 watts, from before. On the other hand, betelgeuse, the upper left star in orion, has a luminosity of 38,000 lsun. In grecian days, hipparchus developed a magnitude system to classify stars according to their brightness. The brightest stars are classified as first magnitude, the next brightest second magnitude, and so on down to sixth or seventh magnitude, for the faintest stars. Today, the system is somewhat more refined and some of the brightest stars have a negative magnitude sirius (the so-called dog star), the brightest star, has a magnitude of 1. 46. So far, we"ve discussed only a star"s brightness.
