y Orionis or Bellatrix, and x Orionis are stars of the 2nd magnitude.
a Orionis, very close to Orionis, is a very fine multiple star, described by Sir William Herschel as two sets of treble stars; more stars have been revealed by larger telescopes.
0 Orionis is a multiple star, situated in the famous nebula of Orion, one of the most beautiful in the heavens.
In 1920 he was able to demonstrate by means of light-interference that the diameter of Alpha Orionis was 260,000,000 miles.
Of multiple stars the most famous is 0 Orionis, situated near the densest part of the great Orion nebula.