Bayer designation

The Bayer naming is a star naming system initiated by Johann Bayer at the beginning of the 17th century in his stellar atlas Uranometria (1603). He assigned the brightest star of a constellation the letter α followed by the Latin genitive of the constellation —for example α Lupi—, the next in brightness the letter β, thus continuing with the lowercase letters of the Greek alphabet for the stars of the constellation. always in brightness or decreasing apparent magnitudes. These letters are called Bayer letters.

In some cases the original Bayer assignment order is incorrect (not always the brightest star is assigned α) or sometimes the modern constellation boundaries do not correspond to Bayer's. Even so, the Bayer name is widely used.

Bayer's system is expanded to be able to designate more stars. First using lowercase Latin letters and then uppercase. Most of these names are rarely used, with a few exceptions, such as P Cygni and l Carinae. Capital Latin Bayer notation never goes beyond Q; names like R Leporis or W Ursae Majoris correspond to variable star names that have nothing to do with the Bayer name.

Superscripts are also used to distinguish double stars that initially had a single Bayer designation, although this is not always unique to double stars, such as the π1, π2, π3, π4, π5, and π6 Orionis chain of stars.

Later, John Flamsteed assigned Arabic numerals to identify the stars in each constellation. In both systems, the letters or numbers are followed by the Latin genitive of the constellation name. Thus, Aldebaran and Elnath are also known as Alpha (α) and Beta (β) Tauri in the Bayer system, or 87 and 112 Tauri in the Flamsteed system, respectively.

In ancient times only a few bright stars were given proper names, the Arabs assigned proper names to many others. The stars may also go by other names, depending on the various catalogs that have been compiled and which they are a part of. In this way, the same star receives many names.