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Alpha Arae

Blue Star in Ara

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Proper Name	None
Bayer Designation	Alpha Arae
Flamsteed Number	None
HR (BSC)	6510
HD	158427
Constellation	Ara
Right Ascension	17h 31m 50s
Declination	-49° 52' 34"
Distance	267 light years 82 parsecs
Magnitude	Apparent: +2.8 Absolute: -1.7
Spectral Class	B2Vne blue main sequence star
Optimum Visibility	June / July (Usually visible from southern latitudes)
Notes	Alpha Arae is a shell star, one of a class of blue stars whose rapid rate of rotation causes a disc of material to form around the star's equator and extend out into space. A hot blue star, Alpha Arae shines with thousands of times the intensity of the Sun.

Alpha Arae is somewhat more massive than the Earth's Sun, and is much brighter and hotter, with a surface temperature of at least 10,000 Kelvin, and probably exceeding 20,000 K. It is highly variable: its brightness in the sky can vary by almost a tenth of a magnitude, perhaps because of variations in brightness on the surface of the star itself.

The brightest of the stars in Ara, the Altar, it lies in the central regions of the band of the Milky Way, about 270 light years (about 80 parsecs) inward across the Galactic disc.

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