Orion's Belt | |
---|---|
Observation data | |
Right ascension | 05h 00m 00s[1] |
Declination | −05° 00′ 00″[1] |
Physical characteristics | |
Associations | |
Constellation | Orion |
Orion's Belt is an asterism in the constellation of Orion. Other names include the Belt of Orion, the Three Kings, and the Three Sisters.[1] The belt consists of three bright and easily identifiable collinear star systems – Alnitak, Alnilam, and Mintaka – nearly equally spaced in a line, spanning an angular size of ~140′ (2.3°).[2]
Owing to the high surface temperatures of their constituent stars, the intense light emitted is blue-white in color. In spite of their spot-like appearance, only Alnilam is a single star; Alnitak is a triple star system, and Mintaka a hextuple. All three owe their luminosity to the presence of one or more blue supergiants. The brightest as viewed from Sol is Alnilam, with an apparent magnitude of 1.69,[3] followed by Alnitak at 1.74[4] and Mintaka at 2.25.[5] The ten stars of the three systems have a combined luminosity approximately 970,000 times that of the Sun.
Orion's Belt appears widely in historical literature and in various cultures, under many different names. It has played a central role in astral navigation in the Northern hemisphere since prehistoric times. It is considered to be among the clearest constellations in the winter sky,[6] although it is not visible during summer, when the Sun is too visually close.
The discredited archeological Orion correlation theory postulated a connection between the positions of the Giza pyramids and those of the belt, with the linkage shown to be spurious when placed within the proper historical context.[7]