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Zuben Elgenubi, Alpha2 Librae, 9 Librae

Proper NamesZubenelgenubi, Zuben Elgenubi
Bayer DesignationAlpha2 Librae
Flamsteed Number9 Librae
HR (BSC)5531
Right Ascension14h 50m 53s
Declination-16° 2' 30"
Distance76 light years
23 parsecs
MagnitudeApparent: +2.8
Absolute: +0.9
Spectral ClassA3IV white subgiant
Optimum VisibilityMay
NotesZubenelgenubi is a complex system comprising a pair of binary stars: both Alpha1 and Alpha2 Librae are spectroscopic binary systems. These two systems evidently shared a common origin and display similar proper motion, travelling through space at a distance of some 5,400 AU apart. There is potentionally another, much more distant, associated star in KU Librae, which also shows proper motion equivalent to the Alpha stars.

The brighter of a pair of stars that lie close to the Ecliptic in Libra. Its name refers to the 'southern claw' of Scorpius - the stars of Libra originally belonged to that constellation.

The fainter fifth-magnitude star close to Zubenelgenubi to the northwest is Alpha1 Librae. Traditionally the name Zubenelgenubi was often shared by these stars as a pair, but the name is now formally applied only to Alpha2 Librae. The two stars do not form a binary system, but they are related; they evidently shared a common origin, and follow similar paths through the Galaxy. Imagery provided by Aladin sky atlas


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