Delta Piscium
Star in the constellation Pisces
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Delta Piscium (δ Piscium) is a solitary,[8] orange-hued star in the zodiac constellation of Pisces. It has an apparent visual magnitude of +4.4,[2] so it is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 10.86 mas, it is around 300 light-years (92 parsecs) from the Sun.[1] The visual magnitude of the star is diminished by an interstellar absorption factor of 0.08 due to interstellar dust.[9]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Pisces |
| Right ascension | 00h 48m 40.9443s[1] |
| Declination | +07° 35′ 06.295″[1] |
| Apparent magnitude (V) | +4.416[2] |
| Characteristics | |
| Spectral type | K4 IIIb[3] |
| U−B color index | +1.831[2] |
| B−V color index | +1.500[2] |
| Astrometry | |
| Radial velocity (Rv) | +32.45±0.18[4] km/s |
| Proper motion (μ) | RA: +81.994 mas/yr[1] Dec.: −50.232 mas/yr[1] |
| Parallax (π) | 10.8577±0.1787 mas[1] |
| Distance | 300 ± 5 ly (92 ± 2 pc) |
| Absolute magnitude (MV) | −0.46[5] |
| Details | |
| Mass | 1.65[3] M☉ |
| Radius | 38.01+0.71 −0.73[6] R☉ |
| Luminosity | 291.7±13.3[6] L☉ |
| Surface gravity (log g) | 1.88[1] cgs |
| Temperature | 3868±35[6] K |
| Metallicity [Fe/H] | −0.19[1] dex |
| Rotational velocity (v sin i) | 5.5[4] km/s |
| Age | 2.98[3] Gyr |
| Other designations | |
| δ Psc, 63 Piscium, BD+06°107, FK5 28, HD 4656, HIP 3786, HR 224, SAO 109474, WDS J00487+0735A[7] | |
| Database references | |
| SIMBAD | data |
This is an evolved K-type giant star with a stellar classification of K4 IIIb.[3] It has around 1.65 times the mass of the Sun and, at the age of three billion years,[3] has expanded to 38[6] times the Sun's radius. The star is radiating 292 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,868 K.[6]
Because Delta Piscium is positioned near the ecliptic, so it is subject to lunar occultations.[10] It has a magnitude 13.99 visual companion at an angular separation of 135.0 arc seconds on a position angle of 12°, as of 2011.[11]
Naming
In Chinese, 外屏 (Wài Píng), meaning Outer Fence, refers to an asterism of stars, δ Piscium, ε Piscium, ζ Piscium, μ Piscium, ν Piscium, ξ Piscium and α Piscium. Consequently, the Chinese name for δ Piscium itself is 外屏一 (Wài Píng yī, English: the First Star of Outer Fence.)[12]