Pi Piscium
Binary star in the constellation Pisces
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Pi Piscium (π Piscium) is a spectroscopic binary[3] star in the zodiac constellation of Pisces. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.60.[2] Based upon an annual parallax shift of 28.50 mas as seen from Earth,[1] it is 114 light years distant. It is a member of the thin disk population of the Milky Way.[7]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Pisces |
| Right ascension | 01h 37m 05.91523s[1] |
| Declination | +12° 08′ 29.5186″[1] |
| Apparent magnitude (V) | 5.60[2] (5.56 + 9.56)[3] |
| Characteristics | |
| Spectral type | F0 V[4] + KV[3] |
| Astrometry | |
| Radial velocity (Rv) | −1.0[2] km/s |
| Proper motion (μ) | RA: −77.29[1] mas/yr Dec.: +9.13[1] mas/yr |
| Parallax (π) | 28.50±0.97 mas[1] |
| Distance | 114 ± 4 ly (35 ± 1 pc) |
| Absolute magnitude (MV) | +2.94[2] |
| Details[3] | |
| A | |
| Mass | 1.42 M☉ |
| Radius | 1.68[a] R☉ |
| Luminosity | 5.45[b] L☉ |
| Surface gravity (log g) | 4.16 cgs |
| Temperature | 6,810 K |
| Metallicity [Fe/H] | −0.10 dex |
| Rotational velocity (v sin i) | 105.9[2] km/s |
| Age | 2.0[5] Gyr |
| B | |
| Mass | 0.75 M☉ |
| Radius | 0.69[a] R☉ |
| Luminosity | 0.207[b] L☉ |
| Temperature | 4,700 K |
| Other designations | |
| π Psc, 102 Piscium, BD+11°205, FK5 1046, GC 1954, HD 9919, HIP 7535, HR 463, SAO 92536, PPM 117498[6] | |
| Database references | |
| SIMBAD | data |
The primary, of apparent magnitude 5.56,[3] is an ordinary F-type main-sequence star with a stellar classification of F0 V.[4] At the estimated age of two billion years,[5] it is about 55% of the way through its main sequence lifetime[8] and still has a relatively high rate of spin with a projected rotational velocity of 105.9 km/s.[2] The star has 1.42 times the mass of the Sun and 1.68[a] of the Sun's radius. It is radiating 5.5[b] times the Sun's luminosity at an effective temperature of 6,810 K.[3] At that temperature, Pi Piscium A has a yellow-white hue, as many F-type stars.[9]
The secondary, of apparent magnitude 9.56, is a K-dwarf star. It is 0.75 times as massive than the Sun, 0.69[a] times as large, and has 21%[b] of the luminosity. Its effective temperature is 4,700 K,[3] giving it an orange hue typical of K-type stars.[9]
Analysis of its motion suggest Pi Piscium may be a member of the Ursa Major association, but higher-quality observations are needed to confirm this.[3]
Naming
In Chinese, 右更 (Yòu Gèng), meaning Official in Charge of the Pasturing, refers to an asterism consisting of π Piscium, η Piscium, ρ Piscium, ο Piscium and 104 Piscium. Consequently, the Chinese name for π Piscium itself is 右更三 (Yòu Gèng sān, English: the Third Star of Official in Charge of the Pasturing.)[10]
Notes
- Calculated, using the Stefan-Boltzmann law and the star's effective temperature and luminosity, with respect to the solar nominal effective temperature of 5,772 K:
- Calculated from the equation L = 100.4 • (4.74 − Mbol, where Mbol is the absolute bolometric magnitude. For component A, a value of 2.90 is used, while for B a value of 6.45 is used.
