And by doing so, we can easily see why this is one of the most prominent asterisms in the sky. Alnitak Ab is a blue dwarf B-type star having an apparent magnitude of 4.3. It lies close to the primary star, Alnitak Aa, just about 11 astronomical units away. Alnitak is a triple star system that is located in the easternmost part of Orion’s Belt. The combined apparent magnitude of its components is 1.77.
Where is the Orion constellation in the sky?
There are three bright stars you can find using Orion’s Belt to guide you. Delta Orionis Ab has a mass 22.5 times that of the Sun and a radius of 10.4 solar radii. It is 63,000 times more luminous than the Sun with a surface temperature of 28,400 K.
Orion constellation facts
The Greek astronomer Ptolemy included Orion as one of the 48 original constellations in the second century. Below the three belt stars, you will find Orion Nebula, which you can view from Earth. Constellations are stars arranged in the shape of an object, person or animal.
- Even though Alnilam is the most distant of the three stars, it appears the brightest because it is the most massive and therefore the most intrinsically luminous of the Belt stars.
- Since Orion’s Belt asterism has been a major fixture in the night sky even in the past, people from around the world have given it different names and related it to their mythology and culture.
- The brightest of these objects, the Orion Nebula (Messier 42), lies below Orion’s Belt and is part of an asterism known as Orion’s Sword.
- For observers in the southern hemisphere, the hourglass figure of Orion appears upside down.
- These were invented – perhaps “imagined” is a better word – by the ancient Greeks, as one might infer from the number of figures in Greek mythology that are represented in the constellations.
- If you join the dots – stars, in this case – and use your imagination, the picture would look like an object, animal, or person.
Because the Earth rotates about its terrestrial poles, the heavens appear to rotate around the celestial poles. The faintest of the four corner stars of Orion, blue-white Saiph – from the Arabic word for ‘sword’ – is another supergiant. Although it’s 56,000 times more luminous than our own Sun, its distance of around 650 lightyears reduces it to mag. This color is caused by a blue supergiant, Anitak A, which is the primary star of the system. It happens to be a class O supergiant – some of the brightest stars visible in the night, and it’s around 30 times as big as our sun. The brightest of these objects, the Orion Nebula (Messier 42), lies below Orion’s Belt and is part of an asterism known as Orion’s Sword.
Orions’ Belt
The Three Stars asterism originally consisted of Alnitak, Alnilam, and Mintaka, and other bright Orion stars – Orion’s Bet Rigel, Betelgeuse, Bellatrix, and Saiph – were added later. Alnitak was known as 參宿一 (Shēn Xiù yī), the First Star of Three Stars, Alnilam as 參宿二 (Shēn Sù èr), the Second Star of Three Stars, and Mintaka as 參宿三 (Shēn Sù sān), the Third Star of Three Stars. In Spain and South America, Orion’s Belt stars are known as Las Tres Marías (Spanish) or As Três Marias (Portuguese), meaning the Three Marys. In Puerto Rico, Mexico and the Philippines they are called Los Tres Reyes Magos, meaning “the three Wise Men,” referring to the Three Kings or the Biblical Magi who visited baby Jesus. In Finland, the asterism and the stars appearing below it are known as Väinämöisen viikate (Väinämöinen’s scythe) or Väinämöisen vyö (Väinämöinen’s Belt). The stars that appear to be hanging from the Belt are known as Kalevanmiekka (Kaleva’s sword).
- So, it is just understandable that a story as old as this is related to one of the most recognizable and universally known asterisms like Orion’s Belt.
- Alnitak Ab is a blue dwarf B-type star having an apparent magnitude of 4.3.
- Remember Mintaka, the star at the far right side of Orion’s belt?
- The story of the Magi related to Orion’s Belt has influenced traditional celebrations across cultures and religions.
- The sky currently includes 88 official, named constellations.
What’s Up: September 2025 Skywatching Tips from NASA
It is estimated that Alnilam will turn into a red supergiant and explode within the next million years. However, the three stars will continue to remain Orion’s belt for many years to come. The asterism is sometimes more commonly known as the Three Kings or Three sisters. The most famous Western culture reference with Orion’s belt is the Three Kings.
A constellation is a named pattern of stars that looks like a particular shape. If you join the dots – stars, in this case – and use your imagination, the picture would look like an object, animal, or person. It’s one of the most recognizable constellations in the night sky and can be seen from around the world. Like the surface of the Earth, the sky can be divided into Northern and Southern Hemispheres (celestial, rather than terrestrial). Whereas points on Earth are described in terms of latitude and longitude, astronomy has units of right ascension and declination.
Earth
Nicknamed “the Stonehenge of the North,” the complex contains three henges that appear to mirror the alignment of Orion’s Belt. Some historians believe that this is not coincidental because the structure had an astronomical purpose. Orion’s Belt has historically carried a lot of significance both in eastern and western cultures. The Great Sphinx of Giza is commonly accepted by Egyptologists to represent the likeness of King Khafre19 who is often credited as the builder as well.
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