It is located in the Northern celestial hemisphere. Its name is Latin for lion , and to the ancient Greeks represented the Nemean Lion killed by the mythical Greek hero Heracles as one of his twelve labors.
One of the 48 constellations described by the 2nd-century astronomer Ptolemy , Leo remains one of the 88 modern constellations today, and one of the most easily recognizable due to its many bright stars and a distinctive shape that is reminiscent of the crouching lion it depicts.
Leo contains many bright stars, many of which were individually identified by the ancients. There are nine bright stars that can be easily seen with the naked eye, four of the nine stars are either first or second magnitude which render this constellation especially prominent. The rest of the three stars form an isosceles triangle, Beta Leonis Denebola marks the lion's tail and the rest of his body is delineated by Delta Leonis and Theta Leonis.
Leo is also home to a bright variable star , the red giant R Leonis. It is a Mira variable with a minimum magnitude of 10 and normal maximum magnitude of 6; it periodically brightens to magnitude 4. R Leonis, light-years from Earth, has a period of days and a diameter of solar diameters.
Wolf is a red dwarf of magnitude It is about 13 billion years old, making it one of the oldest stars in the Galaxy. It has the lowest metallicity of any known star. Modern astronomers, including Tycho Brahe in , excised a group of stars that once made up the "tuft" of the lion's tail and used them to form the new constellation Coma Berenices Berenice's hair , although there was precedent for that designation among the ancient Greeks and Romans.
