We explain what Orion's belt is, its characteristics and what stars make it up. Also, how to find it in the sky.
What is Orion's belt?
Orion's belt, also called in some Hispanic countries “the three wise men” or “the three Marys”, is a stationary set of stars (asterism) that is part of the constellation of Orion and which is made up of three specific stars: Alnitak, Alnilam and Mintaka. This set is considered by astronomers as an open cluster, that is, a set of stars that share an origin and whose organization is usually asymmetric.
The name of this star group is due to the fact that they are located next to each other, in a straight (or almost straight) line, in the center of the constellation of Orion (the hunter). The belt is visible to the naked eye, and is part of the astronomical traditions of very different peoples, such as the Chinese (the Fu Lu Shouthe three beneficent gods), the Egyptian (the three points of the crown of sah) or the Greek (Orion's Belt).
The stars in Orion's belt are relatively young and They are located at an average distance of 1500 light years from Earth. In addition, they are part of one of the best-known constellations in the sky, visible throughout the winter night in the northern hemisphere and summer night in the southern hemisphere.
See also: Celestial bodies
Features of Orion's belt
In general, Orion's belt is characterized by:
- Consists of three young stars visible to the naked eye and located in the Milky Way, each of which is thousands of times larger than our Sun.
- The astronomical cluster to which they belong is called Collinder 70 (Cr-70) and is part of the Orion stellar association OB1.
- are known as “the Three Wise Men” (Melchior, Gaspar and Baltazar) in countries with a Catholic tradition, or as “The Three Marys” or “The Three Holy Women” (Mary Magdalene, Mary Salomé and Mary of Cleopas).
- Supposedly, the three pyramids of Giza, in Egypt, are aligned with the three stars of the belt according to the Orion Correlation Theories (currently considered pseudoscience).
How to find Orion's belt?
To find Orion's belt, you must first locate the constellation of Orion, located near the constellation of the river Eridanus and the constellation Monoceros. Furthermore, Orion is located on his two hunting dogs, according to mythological tradition: the constellations canis major (“The Greater Dog”) and canis minor (“The lesser dog”). The set is also opposite the constellation of Taurus.
Once the constellation of Orion is located, It will be enough to look for the three stars closely located in its center, forming a line slightly diagonal.
Orion's belt can be seen all year round from the equator, while in the northern and southern hemispheres it can be seen only during winter and summer respectively, all night long.
The stars of Orion's belt
The three great stars in Orion's belt are Alnitak, Alnilam and Mintaka, and their names come from Arab tradition, in which they are known as An-nizam (“the pearl belt”). These stars are characterized by:
- Alnitak (Zeta Orionis). It is the southernmost star of the set, located about 700 light years from Earth and endowed with a mass equal to 20 million times that of the Sun. With an age of around 6 million years, it is a very hot star and luminous (100,000 times more luminous than the Sun), and is an important source of space X-rays.
- Alnilam (Epsilon Orionis). It is the brightest star in the Orion constellation and the one that is farthest away, about 1,340 light years from Earth. It is a blue-white supergiant star, with a mass equal to between 30 and 60 million times that of the Sun, whose surface is so hot (25,000 K) that it illuminates the nearby nebula NGC 1990. However, its enormous solar wind makes it lose mass at a rate 20 million times greater than that of the Sun.
- Mintaka (Delta Orionis). It is a multiple star, made up of two major stars separated by just 0.25 light years, and a minor star of less magnitude. Together, they are called Mintaka A, B and C. The most visible of all, with a mass 20 million times that of the Sun, is located 915 light years from Earth and has a luminosity 90,000 times greater than that of the Sun.
Continue with: Orion Nebula
References
- “Orion's Belt” on Wikipedia.
- “Orion (constellation)” on Wikipedia.
- “Orion's Belt” (video) at the Argentine Institute of Astronomy.
- “This is Alnitak, Alnilam and Mintaka, the 3 stars of the 'wise men'” in VERY Interesting.
- “Orion (constellation)” in The Encyclopaedia Britannica.
