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Alnitak

Zeta Orionis, 50 Orionis

Blue-white Star in Orion

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Proper Name	Alnitak
Bayer Designation	Zeta Orionis
Flamsteed Number	50 Orionis
HR (BSC)	1948
HD	37742
Constellation	Orion
Right Ascension	5h 40m 46s
Declination	-1° 56' 33"
Distance	736 light years 226 parsecs
Magnitude	Apparent: +1.7 to +0.6 Absolute: -5.0
Spectral Class	O9Ib Blue-white Supergiant
Optimum Visibility	December / January
Notes	Though only some twelve times the Sun's diameter, this supergiant star emits extraodinary levels of energy: it is some 9,000 times more intrinsically luminous than the Sun in visible light, and produces more than 150,000 times as much energy across the entire spectrum.

The easternmost of the three stars that make up Orion's Belt, Alnitak is a binary. The primary is an O-type supergiant, one of the most luminous of star-types, meaning that shines as brightly as magnitude +1.7 despite being more than 700 light years away.

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