Stellar designations and names

The International Astronomical Union (IAU) is the internationally recognised authority for assigning designations to stars (and other celestial bodies). Many of the star names in use today were inherited from the time before the IAU existed. Others names, mainly for variable stars (including novae and supernovae), are being added all the time. Most stars, however, have no name and are referred to, if at all, by means of catalogue numbers. This article briefly surveys some of the methods used to designate stars.

Proper names

Many of the brighter, or otherwise interesting, stars have proper names. Most of these derive from Arabic, but there are also a few Latin ones, such as Polaris, and even a few English ones, such as Barnard's Star.

Bayer letters

Johann Bayer introduced a system of designating the brightest stars in each constellation by means of Greek (or less often) Latin letters, a system which is still widely used. See Bayer designation for details.

Flamsteed numbers

John Flamsteed's numbering of stars within constellations have also remained popular, although Bayer's Greek letters are usually preferred when there is a choice. See Flamsteed designation for details.

Variable designations

Variable stars which do not have Bayer designations are given special designations which mark them out as variable stars. See variable star designation for details.

Catalogue numbers

In the absence of any better means of designating a star, catalogue numbers are generally used. A great many different star catalogues are used for this purpose, see star catalogues.