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Alpha Equulei, 8 Equulei

Proper NameKitalpha
Bayer DesignationAlpha Equulei
Flamsteed Number8 Equulei
HR (BSC)8131
Right Ascension21h 15m 49s
Declination+5° 14' 52"
Distance190 light years
58 parsecs
MagnitudeApparent: +3.9
Absolute: +0.2
Spectral ClassG5III Yellow Giant
Optimum VisibilityAugust
NotesKitalpha is a binary system in which both components are larger and more luminous than the Sun. The primary star is a yellow subgiant, and this is orbited by a smaller white main sequence star over a period of just under ninety-nine days.

A relatively faint star in the skies of Earth at magnitude +3.9, Kitalpha is nonetheless the brightest of the handful of stars that make up the tiny constellation of Equuleus the Foal, sandwiched between the triangular head of Pegasus and the leaping Dolphin shape of Delphinus in the sky.

Though it is designated Alpha Equulei on the Bayer system, the 'alpha' in its common name Kitalpha has no connection to the first letter of the Greek alphabet. Rather it comes from an anglicised from of Arabic Kitah al Faras, usually translated as meaning a 'piece, or section, of the horse'.

Kitalpha is a yellow star about 186 light years from the Sun. Belonging to the type known as subgiants, it is several times the Sun's diameter, and generates far more energy. Kitalpha is a binary system: the main yellow subgiant has a dwarf companion belonging to the A-type or White spectral classification.


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