Nu Piscium
Star in the constellation Pisces
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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.[3] Based upon an annual parallax shift of 8.98 mas as seen from Earth,[2] it is located about 365 light years from the Sun.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Pisces[1] |
| Right ascension | 01h 41m 25.89414s[2] |
| Declination | +05° 29â² 15.4018â³[2] |
| Apparent magnitude (V) | 4.44[3] |
| Characteristics | |
| Evolutionary stage | red giant branch[2] |
| Spectral type | K3 IIIb[3] |
| BâV color index | 1.37[3] |
| Variable type | Oscillating Red Giant |
| Astrometry | |
| Radial velocity (Rv) | 0.6±0.18[2] km/s |
| Proper motion (μ) | RA: â23.323 mas/yr[2] Dec.: 3.505 mas/yr[2] |
| Parallax (Ï) | 8.9275±0.1567 mas[2] |
| Distance | 365 ± 6 ly (112 ± 2 pc) |
| Absolute magnitude (MV) | â0.78[1] |
| Details | |
| ν Psc A | |
| Mass | 1.66[3] Mâ |
| Radius | 34.58+0.81 â0.83[4] Râ |
| Luminosity | 380[3] Lâ |
| Surface gravity (log g) | 1.91[5] cgs |
| Temperature | 4,154[3] K |
| Metallicity [Fe/H] | â0.16[5] dex |
| Age | 3.41[3] Gyr |
| Other designations | |
| ν Psc, 106 Piscium, BD+04°293, FK5 56, HD 10380, HIP 7884, HR 489, SAO 110065[6] | |
| Database references | |
| SIMBAD | data |
The primary, component A, is an evolved, K-type giant star with a stellar classification of K3 IIIb.[3] It is a weak barium star, indicating that the atmosphere was previously enriched by accretion of s-process elements from what is now a white dwarf companion.[9] The giant has 1.66[3] times the mass of the Sun and has expanded to about 35[4] times the Sun's radius. It is about 3.4 billion years old and is radiating 380 times the Sun's luminosity from its photosphere at an effective temperature of 4,154 K.[3]
In 2026 the star was discovered to be an ORG (Oscillating Red Giant) variable by the Italian amateur research group GrAG (Gruppo Astrofili Galileo Galilei APS).[10]
Naming
In Chinese, å¤å± (Wà i PÃng), 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, the Chinese name for ν Piscium itself is å¤å±äº (Wà i PÃng wu, English: the Fifth Star of Outer Fence.)[11]