Psi Andromedae

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Psi Andromedae
Diagram showing star positions and boundaries of the Andromeda constellation and its surroundings
Cercle rouge 100%.svg

Location of ψ Andromedae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 23h 46m 02.04663s[1]
Declination +46° 25′ 12.9788″[1]
Apparent magnitude (V) 4.95[2]
Spectral type G5 Ib[3] + B9[4]
U−B color index +0.83[2]
B−V color index +1.085[3]
Radial velocity (Rv) -23.62[3] km/s
Proper motion (μ) RA: +9.07[1] mas/yr
Dec.: -7.83[1] mas/yr
Parallax (π) 3.25 ± 0.47[1] mas
Distance approx. 1,000 ly
(approx. 310 pc)
Absolute magnitude (MV) –3.039[3]
ψ And A
Mass 5.4[4] M
Surface gravity (log g) 1.50[3] cgs
Temperature 4,990[3] K
Metallicity [Fe/H] +0.10[3] dex
Age 79[4] Myr
Other designations
20 Andromedae, BD+45°4321, FK5 1622, HD 223047, HIP 117221, HR 9003, SAO 53355.
Database references
Database references

Psi Andromedae (ψ And, ψ Andromedae) is the Bayer designation for a triple star[4] system in the northern constellation of Andromeda. The combined apparent visual magnitude of this system is 4.95.[2] Based upon parallax measurements, is roughly 1,000 light-years (310 parsecs) from Earth, with 14% margin of error.[1]

The primary component has a stellar classification of G5 Ib,[3] which matches the spectrum of an evolved bright giant star. It forms a pair with a star of type B9 with an unknown luminosity class separated by 0.28 arcseconds. A third component has a separation of 0.14 arcseconds. Details of the orbital arrangement remain uncertain.[4]


In Chinese, 螣蛇 (Téng Shé), meaning Flying Serpent, refers to an asterism consisting of ψ Andromedae, α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, β Lacertae, σ Cassiopeiae, ρ Cassiopeiae, τ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae and ι Andromedae,. Consequently, ψ Andromedae itself is known as 螣蛇二十 (Téng Shé èrshí, English: the Twentieth of Flying Serpent)[5]


  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society 133: 475–493, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475. 
  3. ^ a b c d e f g h Soubiran, C.; et al. (March 2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics 480 (1): 91–101, arXiv:0712.1370, Bibcode:2008A&A...480...91S, doi:10.1051/0004-6361:20078788. 
  4. ^ a b c d e Parsons, Sidney B. (May 2004), "New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions", The Astronomical Journal 127 (5): 2915–2930, Bibcode:2004AJ....127.2915P, doi:10.1086/383546. 
  5. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 7 日

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