Theta Orionis Explained

The Bayer designation θ Orionis (Theta Orionis) is shared by several astronomical objects, located near RA DEC :

• θ¹ Orionis (41 Orionis), the Trapezium Cluster, an open star cluster, the Orion OB Association 1d
  • θ¹ Orionis A (41 Orionis A, HD 37020, V1016 Orionis), a trinary star system
  • θ¹ Orionis B (41 Orionis B, HD 37021), a quintet star system
    • θ¹ Orionis B West (COUP 766, MAX 97), an astronomical X-ray source
    • θ¹ Orionis B East (COUP 778, MAX 101), an astronomical X-ray source
  • θ¹ Orionis C (41 Orionis C, HD 37022), a binary star system
  • θ¹ Orionis D (41 Orionis D, HD 37023), a B0.5Vp variable star
  • θ¹ Orionis E (COUP 732), a spectroscopic binary star system
  • θ¹ Orionis F, a B8 variable star at 11th magnitude with a companion
  • θ¹ Orionis G (COUP 826, MAX 116), a young stellar object
  • θ¹ Orionis H (COUP 746, MAX 87), a young stellar object
• θ² Orionis (43 Orionis)
  • θ² Orionis A (43 Orionis, HD 37041), a spectroscopic trinary
  • θ² Orionis B (HD 37042), a B1V variable star
  • θ² Orionis C (HD 37062), a binary star system

The various components are spread over several arc-minutes in and near the Orion Nebula.