Pi Andromedae (Pi And, π Andromedae, π And) is the Bayer designation for a binary star[3] system in the northern constellation of Andromeda. With an apparent visual magnitude of 4.4,[2] it is visible to the naked eye. It is located approximately 580 light-years (180 parsecs) from Earth.[1]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Andromeda |
Right ascension | 00h 36m 52.85132s[1] |
Declination | +33° 43′ 09.6363″[1] |
Apparent magnitude (V) | 4.36[2] (4.9/5.3)[3] |
Characteristics | |
Spectral type | B5 V[4] (B5 V + B5 V[3]) |
U−B color index | –0.55[2] |
B−V color index | –0.16[2] |
Astrometry | |
Radial velocity (Rv) | +8.7[5] km/s |
Proper motion (μ) | RA: 14.669(118)[1] mas/yr Dec.: −3.385(93)[1] mas/yr |
Parallax (π) | 5.6563 ± 0.1474 mas[1] |
Distance | 580 ± 20 ly (177 ± 5 pc) |
Orbit[3] | |
Period (P) | 143.6 days |
Eccentricity (e) | 0.56 |
Details | |
Luminosity | 1,136[6] L☉ |
Surface gravity (log g) | 4.10[4] cgs |
Temperature | 15,276[4] K |
Metallicity [Fe/H] | –0.20[4] dex |
Rotational velocity (v sin i) | 25[7] km/s |
Other designations | |
Database references | |
SIMBAD | data |
The pair is classified as a blue-white B-type main sequence dwarf, with an apparent magnitude of +4.34. It is a spectroscopic binary with an orbital period of 143.6 days and an eccentricity of 0.56. [3]
The spectroscopic binary forms a triple system with BD+32 102, a magnitude 8.6 star located 35.9 arcseconds away.[3] At 55 arcseconds separation is an 11th magnitude companion that is just located on the same line of sight, but at a very different distance from us.
In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of π Andromedae, η Andromedae, 65 Piscium, ζ Andromedae, ε Andromedae, δ Andromedae, ν Andromedae, μ Andromedae, β Andromedae, σ Piscium, τ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, the Chinese name for π Andromedae itself is 奎宿六 (Kuí Sù liù, English: the Sixth Star of Legs.)[8]