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Gamma Orionis, 24 Orionis

Proper NameBellatrix
Bayer DesignationGamma Orionis
Flamsteed Number24 Orionis
HR (BSC)1790
Right Ascension5h 25m 8s
Declination+6° 20' 59"
Distance252 light years
77 parsecs
MagnitudeApparent: +1.59 to +1.64
Absolute: -2.85 to -2.80
Spectral ClassB2III blue giant
Optimum VisibilityDecember / January
NotesA bright blue star that forms the western shoulder of Orion, opposite red Betelgeuse to the east. The blue colouration of this giant star is due to its intensely hot surface, which has a temperature nearly four times that of the Sun.
Location of Bellatrix

Bellatrix is the star that marks Orion's western shoulder. Its eastern counterpart is Betelgeuse, just out of view to the left of this map.

Image of Bellatrix

In common with many stars, the blue giant Bellatrix has a smaller and fainter companion.

Relative Galactic Position of Bellatrix

The Galactic position and direction of Bellatrix relative to Earth's Sun. Note that, at this extreme scale, the two stars are effectively in the same place.

Although its magnitude varies slightly, this blue giant is always prominent. With Betelgeuse, it forms the 'shoulders' of Orion the Hunter.

Bellatrix and its Gaseous Shell

An active star, several times more massive than our Sun, Bellatrix is approaching the end of the current stage of its lifecycle, and is expected to evolve into an orange giant within a matter of a few million years. Already, it has developed a growing shell of gaseous matter that heralds the beginning of its transformation.

Imagery provided by Aladin sky atlas


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