Epoch J2000.0 Equinox J2000.0
|Right ascension||01h 39m 21.0s|
|Declination||+44° 23′ 10″|
|Apparent magnitude (V)||+5.1627|
|Spectral type||G8 III|
|U−B color index||+0.55|
|B−V color index||+0.883|
|Radial velocity (Rv)||+6.54 km/s|
|Proper motion (μ)||RA: –19.78 mas/yr
Dec.: +15.40 mas/yr
|Parallax (π)||13.03 ± 0.55 mas|
|Distance||250 ± 10 ly
(77 ± 3 pc)
|Period (P)||21.5 ± 0.1 yr|
|Eccentricity (e)||0.368 ± 0.020|
|Periastron epoch (T)||43,216 ± 60 MJD|
|Argument of periastron (ω)
|144 ± 3°|
|3.01 ± 0.09 km/s|
|Surface gravity (log g)||2.9 cgs|
|Metallicity [Fe/H]||–0.21 dex|
|Rotational velocity (v sin i)||0.0 km/s|
Chi Andromedae (χ Andromedae, χ And) is the Bayer designation for a star in the northern constellation of Andromeda. It has an apparent visual magnitude of +5.2, which is relatively faint for a naked-eye star. Based upon parallax measurements made during the Hipparcos mission, Chi Andromedae is located around 250 light-years (77 parsecs) from Earth.
It with φ And composed the Chinese asterism 軍南門 (Keun Nan Mun, Mandarin jūnnánmén), "the South Gate of the Camp". χ Andromedae is a member of 天大將軍 (Tiān Dà Jiāng Jūn), meaning Heaven's Great General, together with γ Andromedae, φ Persei, 51 Andromedae, 49 Andromedae, θ Andromedae, τ Andromedae, 56 Andromedae, β Trianguli, γ Trianguli and δ Trianguli. Consequently, χ Andromedae itself is known as 天大將軍五 (Tiān Dà Jiāng Jūn wǔ, English: the Fifth Star of Heaven's Great General.)
This is most likely a spectroscopic binary system with an estimated orbital period of 21.5 years and an eccentricity of 0.37. The primary component has a stellar classification of G8 III, which indicates it is a giant star that has exhausted the supply of hydrogen at its core and evolved away from the main sequence. The outer envelope has expanded to about nine times the radius of the Sun and it is radiating 47 times the luminosity of the Sun at an effective temperature of 5,070 K. This heat gives the star the yellow-hued glow of a G-type star. It appears to be rotating very slowly with no measurable projected rotational velocity.
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