the
Stars
The Naming stars on the celestial sphere are named in several different ways. As a result,
the brighter stars may have more than one name. We give a brief overview of
naming stars here. A somewhat more extensive discussion may be found in
this Sky and Telescope article.
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 systematic more method to name all the
stars that we see. One 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.
As a final example, the brightest star in the nighttime sky is Sirius, which is in
the constellation Canis Major and is termedAlpha Canis Majoris in the Bayer
naming system. Here is a list of 70 of the brighter stars, including common
names, Bayer names, positions on the celestial sphere,
and spectral class.