Nu Piscium

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Nu Piscium
Pisces IAU.svg
Red circle.svg
Location of ν Piscium (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pisces
Right ascension 01h 41m 25.89391s[1]
Declination +05° 29′ 15.4062″[1]
Apparent magnitude (V) 4.44[2]
Spectral type K3 IIIb[2]
B−V color index 1.37[2]
Radial velocity (Rv)+0.76[2] km/s
Proper motion (μ) RA: −23.36[1] mas/yr
Dec.: +3.36[1] mas/yr
Parallax (π)8.98 ± 0.23[1] mas
Distance363 ± 9 ly
(111 ± 3 pc)
Absolute magnitude (MV)−0.78[3]
ν Psc A
Mass1.66[2] M
Radius34±3[4] R
Luminosity380[2] L
Surface gravity (log g)1.91[5] cgs
Temperature4,154±23[2] K
Metallicity [Fe/H]−0.16[5] dex
Age3.41[2] Gyr
Other designations
ν Psc, 106 Piscium, BD+04° 293, FK5 56, HD 10380, HIP 7884, HR 489, SAO 110065[6]
Database references

Nu Piscium (ν Piscium) is an orange-hued binary star[7] system in the zodiac constellation of Pisces. Prior to the formation of the modern constellation boundaries in 1930, it was designated 51 Ceti in the Cetus constellation.[8] Nu Piscium is visible to the naked eye, having a combined apparent visual magnitude of 4.44.[2] Based upon an annual parallax shift of 8.98 mas as seen from Earth,[1] it is located about 363 light years from the Sun.

The primary, component A, is an evolved, K-type giant star with a stellar classification of K3 IIIb.[2] It is a weak barium star, indicating that the atmosphere was previously enriched by accretion of s-process elements from what is now an white dwarf companion.[9] The giant has 1.66[2] times the mass of the Sun and has expanded to about 34[4] times the Sun's radius. It is about 3.4[2] billion years old and is radiating 380[2] times the Sun's luminosity from its photosphere at an effective temperature of 4,154 K.[2]


In Chinese, 外屏 (Wài Píng), meaning Outer Fence, refers to an asterism consisting of ν Piscium, δ Piscium, ε Piscium, ζ Piscium, μ Piscium, ξ Piscium and α Piscium. Consequently, ν Piscium itself is known as 外屏五 (Wài Píng wu, English: the Fifth Star of Outer Fence.)[10]


  1. ^ a b c d e f van Leeuwen, F. (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 d e f g h i j k l m n Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, 88.
  3. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  4. ^ a b Nordgren, Tyler E.; et al. (December 1999), "Stellar Angular Diameters of Late-Type Giants and Supergiants Measured with the Navy Prototype Optical Interferometer", The Astronomical Journal, 118 (6): 3032–3038, Bibcode:1999AJ....118.3032N, doi:10.1086/301114.
  5. ^ a b Prugniel, Ph.; Vauglin, I.; Koleva, M. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769.
  6. ^ "nu. Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-25.
  7. ^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  8. ^ Wagman, M. (August 1987), "Flamsteed's Missing Stars", Journal for the History of Astronomy, 18 (3): 215, Bibcode:1987JHA....18..209W, doi:10.1177/002182868701800305.
  9. ^ Gomez, A. E.; et al. (1997), "Absolute magnitudes and kinematics of barium stars", Astronomy and Astrophysics, 319: 881, Bibcode:1997A&A...319..881G.
  10. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日