Constellation of Orion

Orion, often referred to as "The Hunter," is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the largest, most conspicuous, and most recognizable in the night sky. Its name refers to Orion, a hunter in Greek mythology.

Orion includes the prominent asterism known as the Belt of Orion: three bright stars in a row (The Three Kings). Surrounding the belt at roughly similar distances are four bright stars, which are considered to represent the outline of the hunter's body. Apparently descending from the 'belt' is a smaller line of three stars (one of which is in fact not a star but the Orion Nebula), known as the hunter's 'sword'.
In artistic renderings, the surrounding constellations are sometimes related to Orion: he is depicted standing next to the river Eridanus with his two hunting dogs Canis Major and Canis Minor, fighting Taurus the bull. He is sometimes depicted hunting Lepus the hare.
There are alternative ways to visualize Orion. From the Southern Hemisphere, Orion is oriented differently, and the belt and sword are sometimes called the Saucepan, or Pot in Australia/New Zealand. Orion's Belt is called Drie Konings (Three Kings) or the Drie Susters (Three Sisters) by Afrikaans speakers in South Africa, and are referred to as les Trois Rois (the Three Kings) in Daudet's Lettres de Mon Moulin (1866). The appellation Driekoningen (the Three Kings) is also often found in 17th- and 18th-century Dutch star charts and seaman's guides. The same three stars are known in Latin America as "The Three Marys."
In the tropics (less than 8° from the equator) the constellation transits in the zenith which is best seen in Nov-Feb each year. In the northern hemisphere it is a winter constellation and then it is summer in the southern. However, in Antarctica it is best seen in winter as in summer the Sun does not set and therefore no stars are visible. In winter (May-July) , Orion is in the 'daytime' sky, however for most of Antarctica, the Sun is below the horizon even at midday, so stars (and thus Orion) are visible in at most twilight sky.

Stars

Betelgeuse, known alternatively by its Bayer designation "Alpha Orionis," is a massive M-type red supergiant star nearing the end of its life. When it explodes it will even be visible during the day. It is the second brightest star in the Orion constellation, but was mistakenly classified as the brightest because it is a semiregular variable star and was experiencing a tremendous increase in brightness at the time.[4] It serves as the "right shoulder" of the hunter it represents (assuming that he is facing the observer), and is the twelfth brightest star in the night sky.

Rigel, which is also known as "Beta Orionis," is a B-type blue supergiant that is the sixth brightest star in the night sky. Similar to Betelguese, Rigel is fusing heavy elements in its core and will pass its supergiant stage soon (on an astronomical timescale), either collapsing in the case of a supernova or shedding its outer layers and turning into a white dwarf. It serves as the left foot of Orion, the hunter.

Bellatrix was designated "Gamma Orionis" by Johann Bayer, but is known colloquially as the "Amazon Star;" it is the twenty-second brightest star in the night sky. Bellatrix is considered a B-type blue giant, though it is too small to explode in a supernova. Bellatrix's luminosity is derived from its high temperature rather than its radius,[8] a factor that defines Betelguese.[4] Bellatrix serves as Orion's "left shoulder."

Mintaka garnered the name "Delta Orionis" from Bayer, even though it is the faintest of the three stars in Orion's Belt. It is a multiple star system, composed of a large B-type blue giant and a more massive O-type white star. The Mintaka system constitutes an eclipsing binary variable star, where the eclipse of one star over the other creates a dip in brightness. Mintaka is the westernmost of the three stars that constitute Orion's Belt.

Alnilam was named "Epsilon Orionis," a consequence of Bayer's wish to name the three stars in Orion's Belt (from north to south) in alphabetical order. Alnilam is a B-type blue supergiant, despite being nearly twice as far from the Sun as Mintaka and Alnitak, the other two belt stars, its luminosity makes it nearly equal in magnitude. Alnilam is losing mass quickly, a consequence of its size;[10] approximately four million years old [.

Alnitak was designated "Zeta Orionis" by Bayer, and is the easternmost star in Orion's Belt. It is a triple star some 800 light years distant, with the primary star being a hot blue supergiant and the brightest class O star in the night sky.

Saiph was designated "Kappa Orionis" by Bayer, and serves as Orion's right foot. It is of a similar distance and size to Rigel, but appears much fainter, as its hot surface temperature (46,000°F or 26,000°C) causes it to emit most of its light in the ultraviolet region of the spectrum.

Of the lesser stars, Hatsya (or "Iota Orionis") forms the tip of Orion's sword, whilst Meissa (or "Lambda Orionis") forms the head. In common with many other bright stars, the names Betelgeuse, Rigel, Saiph, Alnitak, Mintaka, Alnilam, Hatsya and Meissa originate from the Arabic language.