Alnilam is a supergiant star of the spectral type B0 Ia, appearing bluish or blue-white in colour.
The history of the star: Alnitak. It is slightly variable, from magnitude 1.64 to 1.74. A fourth star, 9th magnitude Alnitak C, has not been confirmed to be part of the Aa-Ab-B group, and may simply lie along the line of sight. Alnitak B is a 4th magnitude B-type star which orbits Alnitak A every 1500 years. The companion star is a 4th magnitude B-type star, which orbits Alnitak once every 1 508 years or so at a distance of about 3 seconds of arc. The Alnitak system is bathed in the nebulosity of IC 434 which is also associated with the HorseHead Nebula. It is the 29th-brightest star in the sky (the 4th-brightest in Orion) and is a blue supergiant. Alnilam is the middle star of Orion’s Belt, one of the best known asterisms in the night sky, also formed by the bright Alnitak and Mintaka. The star has a visual magnitude of 2.0 and an absolute magnitude of -6.0. It lies only 11 astronomical units from the primary star, which makes the pair a very close binary system. However, the blue supergiant was only recently found to have another companion. It is also one of the 58 stars used in celestial navigation. It has 33 times the Sun’s mass and a radius 20 times that of the Sun.Alnitak Ab has the spectral classification of B1IV, indicating a blue subgiant star. Orion and Orion’s Belt is best seen in mid-December, when it is at its highest in the sky, and in January at 9 pm.German amateur astronomer George K. Hunowsky reported Alnitak to be a double star in 1819. It shares the 31s place with Alnitak is the easternmost star of Orion’s Belt, one of the best known asterisms in the night sky, also formed by the bright Zeta Orionis is a multiple star system with at least three components. Alnitak A is a close binary star, consisting of components Alnitak Aa and Alnitak Ab. Alnitak Aa, the primary star in the Zeta Orionis system, is a hot blue supergiant with the stellar classification O9.5 Iab. It is the brightest class O star in the sky. Best known for the Belt of Orion and the first-magnitude stars Alnitak A is a close binary star, consisting of components Alnitak Aa and Alnitak Ab. The star Alnitak is the primary component of a binary system at the eastern extremity of Orion’s Belt. Alnitak is the 5th brightest star in Orion and the 31st brightest star in the sky. Alnitak Aa, the primary star in the Zeta Orionis system, is a hot blue supergiant with the stellar classification O9.5 Iab. Unlike Alnitak Ab, which can only be detected spectroscopically and interferometrically, Alnitak B can be resolved.The Zeta Orionis stars belong to the Orion OB1 association (subgroup OB1b) and are members of the Collinder 70 open cluster.A fourth star, Alnitak C, can be seen in the vicinity of the system, but it is uncertain whether it is gravitationally bound to it or merely lies in the same line of sight.Alnitak forms the Belt of Orion, one of the most conspicuous asterisms in the sky, with its bright neighbours The stars of Orion’s Belt have had many different names across different cultures. Silhouetted against IC 434 is the famous dark Horsehead Nebula, which lies just south of Alnitak.The nearby Flame Nebula (NGC 2024) is illuminated by the star’s strong ultraviolet light. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. Alnitak is a main star of the constellation outline.
It is about 40 times … Alnitak is the 33rd brightest star in the night sky and the 5th brightest star in Orion based on the Hipparcos 2007 apparent magnitude. from p.314 of Star Names, Richard Hinckley Allen, 1889.. Zeta (ζ) Orion, Alnitak, is a triple star, 2.5, 6.5, and 9, topaz yellow, light purple, and gray, on the east end on the Great Hunter's waist. The three bright stars that form the Orion’s Belt are Alnitak, Alnilam, and Mintaka. Together with Mintaka and Alnitak, the three stars make up Orion's belt, known by many names across many ancient cultures.
It was discovered by a team from the Lowell Observatory in Flagstaff, Arizona.Alnitak is surrounded by the bright emission nebula IC 434. Alnitak, Zeta Orionis (ζ Ori), is a triple star system with a combined apparent magnitude of 1.77. Alnitak Ab is a blue subgiant of spectral type B1IV with an absolute magnitude of -3.9 and an apparent magnitude of 4.3, discovered in 1998.A fourth star, 9th magnitude Alnitak C, has not been confirmed to be part of the Aa-Ab-B group, and may simply lie along the line of sight. Mintaka (d Ori A) is a rather complex multi-star system whose primary component (Aa1) is a very hot, 09.5-type blue giant star that forms a tight eclipsing binary with Aa2, a 7th magnitude B-class main sequence star located roughly 52 seconds of arc away, with the pair having an orbital period of … Alnilam is the middle star. It is the eastern star of Orion’s Belt, appearing to the left of Orion’s Belt and the larger hourglass shape of Orion, outlined by the bright Alnitak is located in the constellation Orion. In Arabic, they are known as In South America and Portugal, the three stars are known as “Las Tres Marías” (Spanish) and “As Três Marias” (Portuguese).