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Alpha Boötis, 16 Boötis

Proper NameArcturus
Bayer DesignationAlpha Boötis
Flamsteed Number16 Boötis
HR (BSC)5340
Right Ascension14h 15m 40s
Declination+19° 10' 57"
Distance37 light years
11 parsecs
MagnitudeApparent: -0.1
Absolute: -0.3
Spectral ClassK0 Orange Giant
Optimum VisibilityMay
NotesThe brightest star in the northern sky, Arcturus belongs to two major asterisms, the Great Diamond and the Spring Triangle. This orange giant is an oscillating variable star, and there is evidence that it has binary companion, much fainter than the primary orange star.

Arcturus is the fourth brightest star in the sky: only Sirius, Canopus and Alpha Centauri outshine this orange giant. It is a variable star in the last stages of its life, and relatively nearby at just 37 light years' distance.

Imagery provided by Aladin sky atlas


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