Star
The Sun has an apparent magnitude of −26.7, but its absolute magnitude is only +4.83. Sirius, the brightest star in the night sky as seen from Earth, is approximately 23 times more luminous than the Sun, while Canopus, the second brightest star in the night sky with an absolute magnitude of −5.53, is approximately 14,000 times more luminous than the Sun. Despite Canopus being vastly more luminous than Sirius, however, Sirius appears brighter than Canopus. This is because Sirius is merely 8.6 light-years from the Earth, while Canopus is much farther away at a distance of 310 light-years.
Alpha Centauri in fiction
Alpha Centauri, a double star system with the binary designation Alpha Centauri AB, is the brightest visible object in the southern constellation Centaurus. Its component stars are Alpha Centauri A (the primary—somewhat larger and brighter than the Sun) and Alpha Centauri B (the secondary—slightly smaller and dimmer). These stars are of spectral classes G2V (as is the Sun) and K1V, respectively; in the former case there is an obvious model and potential for planets capable of supporting complex biospheres, and in the latter, as it turns out, an even stronger probability of a stable habitable zone that is well suited for life. (Proxima Centauri—a late-discovered red dwarf, and the closest known star to the Solar System) appears to be gravitationally bound to the AB system although at a considerable distance. The collection of three stars together is called Alpha Centauri AB-C.