Orion's Belt stars—Alnitak, Alnilam, and Mintaka—move through space at the same speed because they were born from the same cloud of gas and dust.

Orion's Belt stars belong to the Orion OB1 association, a group of dozens of hot, massive stars located approximately 1,200 to 1,500 light-years from Earth. Alnitak, Alnilam, and Mintaka are part of the OB1b subgroup, which formed about 10 million years ago when a massive interstellar nebula collapsed. Because they originated from the same rotating cloud of gas, they inherited identical initial momentum and trajectory through the galaxy.These three stars are classified as blue supergiants—among the hottest and most luminous stars known. Alnilam, the central star, is particularly remarkable, shining nearly 375,000 times brighter than our Sun. Despite their enormous size and power, these stars have short lifespans and are expected to explode as supernovae within the next few million years.Astronomers use the European Space Agency's Gaia satellite to measure the precise proper motion and radial velocity of these stars. Data from the Gaia DR3 release confirms they maintain a consistent velocity of roughly 450 kilometers per second relative to the galactic center. This shared motion enables researchers to trace the history of the Orion Molecular Cloud Complex and understand how star clusters form and evolve.