Leo

Leo is one of the constellations of the zodiac, lying between Cancer to the west and Virgo to the east. Its name is Latin for lion, and to the ancient Greeks represented the Nemean Lion killed by the mythical Greek hero Heracles (known to the ancient Romans as Hercules) as one of his twelve labors. Its symbol is ( ♌). 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. The lion's mane and shoulders also form an asterism known as "the Sickle," which to modern observers may resemble a backwards "question mark."

Stars

Leo contains many bright stars, many of which were individually identified by the ancients. There are four stars of first or second magnitude, with render this constellation especially prominent:

• Regulus, designated Alpha Leonis, is a blue-white main-sequence star of magnitude 1.34, 77.5 light-years from Earth. It is a double star divisible in binoculars, with a secondary of magnitude 7.7. Its traditional name (Regulus) means "the little king".
• Beta Leonis, called Denebola, is at the opposite end of the constellation to Regulus. It is a blue-white star of magnitude 2.23, 36 light-years from Earth. The name Denebola means "the lion's tail".
• Algieba, Gamma Leonis, is a binary star with a third optical component; the primary and secondary are divisible in small telescopes and the tertiary is visible in binoculars. The primary is a gold-yellow giant star of magnitude 2.61 and the secondary is similar but at magnitude 3.6; they have a period of 600 years and are 126 light-years from Earth. The unrelated tertiary, 40 Leonis, is a yellow-tinged star of magnitude 4.8. Its traditional name, Algieba, means "the forehead".
• Delta Leonis, called Zosma, is a blue-white star of magnitude 2.58, 58 light-years from Earth. Epsilon Leonis is a yellow giant of magnitude 3.0, 251 light-years from Earth.
• Zeta Leonis, called Adhafera, is an optical triple star. The brightest and only star designated Zeta Leonis, is a white giant star of magnitude 3.65, 260 light-years from Earth. The second brightest, 39 Leonis, is widely spaced to the south and of magnitude 5.8. 35 Leonis is to the north and of magnitude 6.0.Iota Leonis is a binary star divisible in medium amateur telescopes; they are divisible in small amateur telescopes at their widest (2053-2063). To the unaided eye, Iota Leonis appears to be a yellow-tinged star of magnitude 4.0. The system, 79 light-years from Earth, has components of magnitude 4.1 and 6.7 with a period of 183.Tau Leonis is a double star visible in binoculars. The primary is a yellow giant of magnitude 5.0, 621 light-years from Earth. The secondary is a star of magnitude 8.54 Leonis is a binary star 289 light-years from Earth, divisible in small telescopes. The primary is a blue-white star of magnitude 4.5 and the secondary is a blue-white star of magnitude 6.3.

HGS Session References

HGS Sessions - Clearing Planetary Diagonal Channels - 3/14/2015

See Also

Four Royal Stars

Found in HGS Manual on Page 108 Found in HGS Manual on Page 115