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Bellatrix

Gamma Orionis, 24 Orionis

Blue Star in Orion

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Proper Name	Bellatrix
Bayer Designation	Gamma Orionis
Flamsteed Number	24 Orionis
BSC	1790
HD	35468
Constellation	Orion
Right Ascension	5h 25m 13s
Declination	+6° 21' 1"
Distance	243 light years 75 parsecs
Magnitude	Apparent: +1.5 to +1.6 Absolute: -2.8
Spectral Class	B2 Blue Giant
Optimum Visibility	December/January
Notes	A 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.

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.

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

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.

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.

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