Gamma Orionis (Bellatrix)

γ Orionis
Gamma Orionis (Bellatrix: The Female Warrior) is appropriately found on the Hunter's left (distaff) shoulder, or on the upper right corner of Orion to an observer.

About 20 million years old, Bellatrix is evolving into a giant star; presently it's about six times the radius of the Sun.

The region around gamma is chock-a-block with binaries; no less than four of the many binaries here are suitable for small telescopes:
       23 Ori (Struve 696): 4.9, 6.8; 30º, 31.9".
       32 Ori (Struve 728)AB: 4.4, 5.8; 43º, 1.4" orbit
       Struve 712AB: 6.7, 8.6; 66º, 3.1".
       Struve 721A-BC: 7.1, 9.1; 149º, 24.5".

An outlier to this grouping is rho Orionis (Struve 654), two degrees west of 21 Orionis: 4.6, 8.5; 63º, 6.8".

From gamma, move one binocular field north and very slightly east, to lambda.

Lambda Orionis represents the head of Orion; its name Meissa (‘the Shining One’) was first used for gamma Geminorum, but later was applied to this star instead.

A blue giant, ten times the Sun's radius, Meissa is know for its super hot surface temperature—35,000 Kelvin—which makes it one of the hottest in the heavens (eta Carinae leads that list, at about 41,000 Kelvin).

Lambda Orionis is a multiple binary system with mostly wide but faint companions (Struve 738):
       AB 3.5, 5.5; 44º, 4.2".
       AC: 3.5, 10.7; 186º, 29.3".
       AD: 3.5, 9.6; 272º, 78.5".
       AE: 3.5, 9.2; 279º, 151.1".

North of lambda, only 14 arcminutes, is the delightful binary Otto Struve 111, with the fainter companion practically due north of the primary: 5.6, 9.7; 351º, 2.8".

Two binocular fields west are pi1 and pi2; from here south is a row of six pi stars which denote Orion's shield. North of pi1 one binocular field are the two omicrons: binoculars.

One and a half degrees northeast of omicron2 is the binocular-accessible multiple binary Sh 49:
       AB: 6.1, 7.4; 307º, 39.2".
       AC: 6.1, 9.6; 90º, 54.4".

All files associated with The Constellations Web Page are
© 1998-2014 by Richard Dibon-Smith.