Gamma Piscium

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Gamma Piscium[1]
Diagram showing star positions and boundaries of the Pisces constellation and its surroundings
Cercle rouge 100%.svg

Location of γ Piscium(circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Pisces
Right ascension 23h 17m 09.93749s[2]
Declination +03° 16′ 56.2380″[2]
Apparent magnitude (V) 3.699[3]
Spectral type G9 III:[1]
U−B color index +0.572 [3]
B−V color index +0.924[3]
Radial velocity (Rv) -13.6[4] km/s
Proper motion (μ) RA: 759.82[2] mas/yr
Dec.: 17.77[2] mas/yr
Parallax (π) 23.64 ± 0.18[2] mas
Distance 138 ± 1 ly
(42.3 ± 0.3 pc)
Absolute magnitude (MV) 0.68 ± 0.08[5]
Mass 1.03 ± 0.17[5] M
Radius 9.92 ± 0.42[5] R
Surface gravity (log g) 2.43 ± 0.06[5] cgs
Temperature 4,885[5] K
Metallicity [Fe/H] −0.51[5] dex
Age 5.46 ± 2.50[5] Gyr
Other designations
γ Piscium, γ Psc, Gamma Psc, 6 Piscium, BD+02°4648, FK5 878, GC 32415, HD 219615, HIP 114971, HR 8852, PPM 173938, SAO 128085, GC 32415.[1]

Gamma Piscium (Gamma Psc, γ Piscium, γ Psc) is a star approximately 138 light years away from Earth,[6] in the zodiac constellation of Pisces. It is a yellow star with a spectral type of G9 III, meaning it has a surface temperature of 4,885 K and is a giant star. It is slightly cooler than our Sun, yet it is 10[5] solar radii in size and shines with the light of 61 Suns.[7] At an apparent magnitude of 3.7,[3] it is the second brightest star in the constellation Pisces, between Eta and Alpha. Once a white A2 star, it is 5.5 billion years old.

Gamma Piscium moves across the sky at three-quarters of an arcsecond per year, which at 138 light years corresponds to 153 kilometers per second. This suggests it is a visitor from another part of the Milky Way Galaxy; in astronomical terms, it will quickly leave the vicinity of the Sun. Its metallicity is only one-fourth that of the Sun, and visitors from outside the thin disk that composes the Milky Way tend to be metal-poor. It also has a low carbon-nitrogen content.[7] Gamma Piscium lies inside an asterism known as the "circlet of Pisces."[8]


In Chinese, 霹靂 (Pī Lì), meaning Thunderbolt, refers to an asterism consisting of refers to an asterism consisting of γ Piscium, β Piscium, θ Piscium, ι Piscium and ω Piscium. Consequently, γ Piscium itself is known as 霹靂二 (Pī Lì èr, English: the Second Star of Thunderbolt.)[9]

In fiction[edit]

In Frank Herbert's Dune series, Gamma Waiping (The Chinese name for Pisces) is the home system of Imperial House Corrino.


  1. ^ a b c "Simbad Query Result", Simbad, retrieved September 30, 2007 
  2. ^ a b c d e 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 
  3. ^ a b c d Cousins, A. W. J. (1984), "Standardization of Broadband Photometry of Equatorial Standards", South African Astronomical Observatory Circulars 8: 59, Bibcode:1984SAAOC...8...59C 
  4. ^ Wielen, R.; et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W 
  5. ^ a b c d e f g h da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105 
  6. ^ van Leeuwen, F. (2007), "HIP 114971", Hipparcos, the New Reduction, retrieved 2010-08-30 
  7. ^ a b "Gamma Psc". Retrieved September 30, 2007. 
  8. ^ " -- SpaceWatch -- Pisces Rising". Retrieved September 30, 2007. 
  9. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 8 日