Orion constellation: Encyclopedia II - Orion constellation - Notable features

Orion constellation - Notable features

The constellation is extremely rich in bright stars and in deep-sky objects. Here are some of its stars:

• λ Ori (Meissa) is Orion's head.
• α Ori (Betelgeuse), at its right shoulder, is a red star, larger than the orbit of Venus. Although it is the α-star, it is somewhat fainter than Rigel. Betelgeuse is actually a sextuple star, but its companions are too small to be easily seen. It forms a point of the Winter Triangle.
• γ Ori (Bellatrix), "warrior woman", is at Orion's left shoulder.
• ζ Ori (Alnitak), ε Ori (Alnilam) and δ Ori (Mintaka) make up the asterism known as Orion's Belt: three bright stars in a row; even from these alone one can recognize Orion.
• η Ori (Eta Orionis), between Delta Orionis and Rigel.
• κ Ori (Saiph) is at Orion's right knee.
• β Ori (Rigel), at the constellation's left knee, is a large blue-white star, among the brightest in the sky. It has three companions, also difficult to see.
• ι Ori (Hatsya) is at the tip of Orion's sword.

The major stars of Orion are all very similar in age and physical characteristics, suggesting that they may have a common origin. Betelgeuse is the single exception to this.

Orion is very useful in locating other stars. By extending the line of the Belt southeastward, Sirius (α CMa) can be found; northwestward, Aldebaran (α Tau). A line eastward across the two shoulders indicates the direction of Procyon (α CMi). A line from Rigel through Betelgeuse points to Castor and Pollux (α Gem and β Gem).

Adapted from the Wikipedia article "Notable features", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki