Orion

Origin

Orion is a prominent constellation during winter in the northern hemisphere. As it lies near the celestial equator, it is visible from most of the world. It is one of the 88 modern constellations and was among the 48 constellations listed by the second-century astronomer Ptolemy. It is named for a mythological hunter in Greek mythology. The Sumerians saw Orion as Gilgamesh fighting a bull, Taurus.

Bright Stars

Orion's seven brightest stars form a distinctive hourglass-shaped asterism, or pattern, in the night sky. Four stars — Rigel, Betelgeuse, Bellatrix, and Saiph — form a large, roughly rectangular shape, at the center of which lie the three stars of Orion's Belt — Alnitak, Alnilam, and Mintaka. His head is marked by an additional eighth star called Meissa, which is fairly bright to the observer. Descending from the ‘belt’ is a smaller line of three stars, Orion's sword (the middle of which is in fact not a star but the Orion Nebula), also known as the hunter's sword.

Many of the stars are luminous hot blue supergiants, with the stars of the belt and sword forming the Orion OB1 association. Standing out by its red hue, Betelgeuse may nevertheless be a runaway member of the same group.

• Betelgeuse, also designated Alpha Orionis, is a massive red supergiant star. It is the second brightest star in Orion, and is a semiregular variable star.
• Rigel, also known as Beta Orionis, is the sixth-brightest star in the night sky.
• Bellatrix is designated Gamma Orionis and is the twenty-seventh-brightest star in the night sky.
• Mintaka is designated Delta Orionis and is the faintest of the three stars in Orion's Belt. Its name means ‘the belt’.
• Alnilam is designated Epsilon Orionis and is named for the Arabic phrase meaning string of pearls. It is the middle and brightest of the three stars of Orion's Belt.
• Alnitak, meaning ‘’the girdle’, is designated Zeta Orionis. It is a triple star system.
• Saiph is designated Kappa Orionis by Bayer, It means ‘the sword of the giant’.
• Meissa is designated Lambda Orionis is one of the stars that forms Orion's head. Its name means ‘the "shining one’. It is a multiple star with an apparent magnitude of 3.33.