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Alpha Arae

Proper NameNone
Bayer DesignationAlpha Arae
Flamsteed NumberNone
HR (BSC)6510
Right Ascension17h 31m 50s
Declination-49° 52' 34"
Distance267 light years
82 parsecs
MagnitudeApparent: +2.8
Absolute: -1.7
Spectral ClassB2Vne blue main sequence star
Optimum VisibilityJune / July (Usually visible from southern latitudes)
NotesAlpha 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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