Alnitak
HIP 26727; Zeta Ori; 50 Ori
Object Data
- Catalog Designation
- HIP 26727; Zeta Ori; 50 Ori
- Type
- DoubleStar
- Constellation
- Ori
- Magnitude
- 2.05
- Right Ascension
- 05h 40m 45.5s
- Declination
- -01° 56' 34.0"
- Distance
- 136 light-years
- HR
- 1948
- HIP
- 26727
- Bayer
- Zeta
Survey Image
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About Alnitak
Description
Alnitak is the easternmost star of Orion's Belt at magnitude 2.05, a hot blue supergiant of spectral type O9.7Ib. Located about 1,200 light-years from Earth, it has a luminosity of roughly 250,000 times solar — one of the most luminous stars in the Orion region. Alnitak is a triple star system; the close companion is resolvable in moderate telescopes.
Observing Tips
Alnitak is the left (eastern) star of Orion's Belt. Just south of Alnitak lies the famous Horsehead Nebula (B33) and the bright Flame Nebula (NGC 2024) — both illuminated by Alnitak's intense radiation. The Belt stars are among the easiest patterns to identify in the entire sky. Best observed December through March.
History
The name Alnitak comes from the Arabic 'al-nitaq,' meaning 'the girdle' or 'the belt.' Together with Alnilam and Mintaka, the three Belt stars have been recognized and named across virtually every culture. They were 'the Three Kings,' 'the Three Marys,' and 'the String of Pearls' in various traditions.
Fun Facts
Alnitak is responsible for illuminating the Flame Nebula and creating the silhouette of the famous Horsehead Nebula, one of the most photographed objects in the sky. The star is so energetic that its ultraviolet light ionizes the gas clouds over a light-year away.