Alpha Equulei

α Equulei

Template:Location mark Location of α Equulei (circled)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Equuleus
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	+3.919(4.49/4.96)
Characteristics
Spectral type	G7III + kA3hA4mA9
U−B Template:Engvar	+0.284
B−V Template:Engvar	+0.529
Astrometry
Radial velocity (Rv)	−15.71 ± 0.05 km/s
Proper motion (μ)	RA: +59.88 ± 0.23 mas/yr Dec.: −94.09 ± 0.18 mas/yr
Parallax (π)	17.14±0.21 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	+0.17 (0.71 + 1.18)
Orbit
Period (P)	98.8098 days
Eccentricity (e)	0
Semi-amplitude (K1) (primary)	16.34 ± 0.07 km/s
Semi-amplitude (K2) (secondary)	17.9 ± 0.3 km/s
Details
A
Mass	2.3 Template:Solar mass
Radius	9.2 Template:Solar radius
Luminosity	52.5 Template:Solar luminosity
Temperature	5,100 K
Rotational velocity (v sin i)	20.0 km/s
B
Mass	2.0 Template:Solar mass
Radius	2.6 Template:Solar radius
Luminosity	26.3 Template:Solar luminosity
Temperature	8.150 K
Metallicity [Fe/H]	{{{metal_fe2}}} dex
Age	740 Myr
Other designations
Kitalphar, 8 Equulei, HR 8131, HD 202447, BD+04 4635, HIP 104987, SAO 126662, FK5 800, GC 29735
Database references
SIMBAD	data

Alpha Equulei (α Equulei, abbreviated Alpha Equ, α Equ), officially named Kitalpha Template:IPAc-en, is a star in the constellation of Equuleus. It is a high proper-motion star only 190 light-years away.

Nomenclature

α Equulei (Latinised to Alpha Equulei) is the star's Bayer designation.

It bore the traditional name Kitalpha (rarely Kitel Phard or Kitalphar), a contraction of the Arabic name قطعة الفرس qiṭ‘a(t) al-faras—"a piece of the horse". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Kitalpha for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.

In Chinese, (), meaning Emptiness, is an asterism consisting of Alpha Equulei and Beta Aquarii. Consequently, the Chinese name for Alpha Equulei itself is (, Template:Langx).

Properties

The overall appearance of α Equulei is a G-type giant with an apparent magnitude of +3.92, but it is a spectroscopic binary consisting of two individual stars.

The primary star is a G7 giant about fifty times more luminous than the Sun. It has an effective temperature of Template:Val and a radius of 9.2 times greater than the Sun.

The secondary is an A-type dwarf about 26 times as luminous as the sun. It has an effective temperature of 8,150 K and a radius 2.6 times greater than the sun. It is a chemically peculiar Am star.

The two stars revolve in a circular orbit every 98.8 days. Their respective orbital velocities allow their masses to be calculated at Template:Solar mass and Template:Solar mass, respectively.