The star system is composed of Alnitak Aa – a blue supergiant of spectral type O9.5lab, Alnitak Ab – a blue subgiant of spectral type B1lV, and Alnitak B – a B-class blue giant star.

It was reported to be a double star by amateur German astronomer George K. Kunowsky in 1819. Alnitak B is a class B giant star with a visual magnitude of 4.01.

They lie from 800 to 1,500 light-years away, born of Orion's well-studied interstellar clouds. According to Solara, the 'galactic' name for this star is RA. Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (lower right to upper left) along the diagonal in this cosmic vista. Much more recently, in 1998, the bright primary was found by a team from the Lowell Observatory to have a close companion; this had been suspected from observations made with the Narrabri Stellar Intensity Interferometer in the 1970s. Two contact cases refer to one or two planets that could be located in the vicinity of Alnitak: Nep-4, mentioned in the contact case of Oswald Gonzalez. The Zeta Orionis stars belong to the Orion OB1 association (subgroup OB1b) and are members of the Collinder 70 open cluster. Alnitak has been known since antiquity and, as a component of Orion's belt, has been of widespread cultural significance. It orbits Alnitak A every 1,508.6 years. Unlike Alnitak Ab, which can only be detected spectroscopically and interferometrically, Alnitak B can be resolved. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. Zeti, mentioned in the contact case of Raphael Chacun.