Alpha Equulei

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**Alpha Equulei**
Observation data Epoch J2000.0
Constellation (pronunciation)	Equuleus
Right ascension	21^h 15^m 49.40^s
Declination	+5° 14' 53.1"
Apparent magnitude (V)	+3.92
Absolute magnitude (V)	+0.14
Distance	186 ly (57.05 pc)
Spectral type	G0III+
Other designations
Kitalphar, 8 Equulei, HR 8131, HD 202447, BD +04 4635, HIP 104987, SAO 126662, FK5 800, GC 29735

Alpha Equulei (α Equ / α Equulei) is a star in the constellation Equuleus. It also has the traditional name Kitalpha or Kitalphar, which is a contraction of the Arabic title Qit'at al Faras (قطعة الفرس), meaning "Part of the Horse".

Alpha Equulei collectively belongs to spectral class G0III and has apparent magnitude +3.92 and a luminosity approximately 75 times that of the Sun. However, the star deceives. Alpha Equulei is a unique spectroscopic binary star consisting of two components. The two stellar components within the system are so close together that the class is mixed, G + A, two spectra present at the same time. The brighter of the two (by about 50%, 45 times brighter than the Sun) is a class G (G0) giant, the fainter a white class A (A5) dwarf. The giant is in the process of dying and most likely (like the dimmer component of Capella) has a contracting helium core, while the dwarf is a common unevolved hydrogen-fuser. The blend of starlight makes actual temperatures difficult to measure, but should respectively be around 5500 and 8500 kelvins. The Kitalpa is approximately 186 light years from Earth.