The brightest magnitude a variable star reaches is called its maximum, while the faintest magnitude is its minimum. The difference between the star's maximum and minimum is its amplitude, and the time between successive maxima or minima is called the period. A light curve is a plot of the star's changing brightness over time.
Many variables have common names or Bayer Greek letters, but others are known by their official vanable-star designation—for example, 11 Leonis or X Aquarn. The letters R to Z are used for the first variables discovered in a constellation. Additional vari-ables are assigned KR- to RZ, SS to SZ, and so on, up to ZZ. The sequence then progresses from AA to AZ, BB to BZ, and concludes with QZ. Since there are only 334 available letter combinations, the 335th variable in a constellation is labeled V335, and so on.