Naming the StarsThe stars on the celestial sphere are named in several different ways. As a result, the brighter stars may have more than one name. Here is a brief overview of naming stars. A somewhat more extensive discussion may be found here. Common Names
Most of the brighter stars in the sky have common names that are of historical
and mythological significance. For example, the bright red star in the shoulder
region of the constellation Orion (the Hunter) is called Betelgeuse, which comes
from Arabic and means (roughly) "the armpit of the mighty one" (see
adjacent figure). The brightest star in Orion is a blue-white star called Rigel
that is situated at the opposite corner of the constellation from Betelgeuse
(adjacent figure).
As another example, the brightest star in the constellation Cygnus (the Swan) is situated near the aft portion of the beast and is called Deneb, which is also Arabic in origin and means "the tail of the hen". The Bayer Naming System Common names are fine for a few bright stars, but we need a more systematic
method to name all the stars that we see. A more systematic method is the
Bayer system, which names the brighter stars by assigning a constellation (using
the Latin possessive of the name) and a Greek letter (Alpha, Beta, Gamma, Delta,
Epsilon, . . .) in an approximate order of decreasing brightness for stars in
the constellation. The adjacent figure illustrates for Orion. Betelgeuse is also
called Alpha-Orionis and Rigel is called Beta Orionis in the
Bayer system.
The ordering of stars by brightness in the classical Bayer system is only approximate. For example, Rigel (Beta Orionis) is actually slightly brighter than Betelgeuse (Alpha Orionis), and Kappa Orionis is considerably brighter than the position of Kappa in the Greek alphabet would suggest.
The Flamsteed Naming SystemThe Bayer system is a little more systematic than a set of common names, but there are only a finite number of letters in the Greek alphabet, so it cannot be used easily to name very many stars. The Flamsteed naming system can in principle be used to name any number of stars. In this system one uses the same Latin possessive of the constellation name as in the Bayer system, but the stars are distinguished, not by their brightness, but by their nearness to the western edge of the constellation by assigning an Arabic numeral. Thus, the closest star to the western edge of the constellation Cygnus is called 1-Cygni in the Flamsteed system and 61-Cygni denotes the star that is the 61st closest to the western edge.Star CatalogsThere are various specialized star catalogs in which stars may be given names according to some convention. Such specialized catalogs are of importance in astronomical research.updated: |
As a final example, the brightest star in the nighttime sky is Sirius, which is
in the constellation Canis Major and is termed Alpha Canis Majoris in
the Bayer naming system.