wavelengths of light, and these apparent magnitudes vary dramatically in the different systems. For example, Betelgeuse has the K-band (infrared) apparent magnitude of −4.05. Some stars, like Betelgeuse and Antares, are variable stars, changing their magnitude over days, months or years. In the table, the range of variation is indicated with the symbol "var". Single magnitude values quoted for variable stars come from a variety of sources. Magnitudes shown in the table are either when the stars are at maximum brightness, which is repeated for every cycle (e.g. the eclipsing binary Algol); or, if the variations are small, a simple average magnitude. For red variable stars, specifying a single maximum brightness is often difficult because each cycle produces a different maximum brightness; this is thought to be caused by poorly understood pulsations in stellar evolution processes. Such quoted stellar brightness is sometimes based on the average maximum apparent magnitude from estimated maxima over many observed light-curve cycles, sometimes spanning across centuries. Results often quoted in the literature are not necessarily straightforward and may differ in expressing an alternate value for a singular maximum brightness or as a range of values. A few selected stars, thought to be uniformly fixed in brightness, are used as standard stars. These standard stars have carefully determined magnitudes that have been analysed over many years, and are often used to determine other stars' magnitudes or their stellar parameters using comparatively consistent scales. Nomenclature All of these stars have multiple valid names or catalogue designations. The table lists their Bayer designation and the most common proper name. Most of the proper names have been approved by the Working Group on Star Names of the International Astronomical Union (IAU). Popular names which have not been approved by the IAU are omitted. Table The source of magnitudes cited in this list is the linked Wikipedia articles. This basic list is a catalog of what Wikipedia itself documents. References can be found in the individual articles. See also References External links The Magnitude system About stellar magnitudes The clickable brightest stars Lists of stars Stars, List of Brightest Stars, brightest