Psi1 Piscium
Binary star in the constellation Pisces
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Psi1 Piscium (Psi1 Psc, ψ1 Piscium, ψ1 Psc) is a binary star in the constellation Pisces. It is approximately 280 light years from Earth, based on its parallax.[1]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pisecs |
| ψ1 Psc A | |
| Right ascension | 01h 05m 40.95527s[1] |
| Declination | +21° 28′ 23.4489″[1] |
| Apparent magnitude (V) | 5.273[2] |
| ψ1 Psc B | |
| Right ascension | 01h 05m 41.71111s[3] |
| Declination | +21° 27′ 55.6120″[3] |
| Apparent magnitude (V) | 5.455[2] |
| Characteristics | |
| ψ1 Psc A | |
| Spectral type | A1V + A4V[4] |
| U−B color index | −0.12[5] |
| B−V color index | −0.04[5] |
| ψ1 Psc B | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A0Vn[6] |
| U−B color index | −0.17[5] |
| B−V color index | −0.06[5] |
| Astrometry | |
| ψ1 Psc A | |
| Radial velocity (Rv) | −3.90±2.9[7] km/s |
| Proper motion (μ) | RA: 44.49[1] mas/yr Dec.: −14.82[1] mas/yr |
| Parallax (π) | 11.86±0.68 mas[1] |
| Distance | 280 ± 20 ly (84 ± 5 pc) |
| Absolute magnitude (MV) | +0.71[8] |
| ψ1 Psc B | |
| Radial velocity (Rv) | −7.20±3.6[9] km/s |
| Proper motion (μ) | RA: 54.952[3] mas/yr Dec.: −15.938[3] mas/yr |
| Parallax (π) | 11.3778±0.0506 mas[3] |
| Distance | 287 ± 1 ly (87.9 ± 0.4 pc) |
| Absolute magnitude (MV) | +0.89[8] |
| Orbit[4] | |
| Primary | ψ1 Psc Aa |
| Name | ψ1 Psc Ab |
| Period (P) | 14.44±0.26 yr |
| Semi-major axis (a) | 114.3±1.7″ |
| Eccentricity (e) | 0.519±0.027 |
| Inclination (i) | 77.43±0.81° |
| Longitude of the node (Ω) | 134.8±1.2° |
| Periastron epoch (T) | B 2007.512±0.041 |
| Argument of periastron (ω) (secondary) | 305.4±2.3° |
| Details | |
| ψ1 Psc Aa | |
| Mass | 2.2[10] M☉ |
| ψ1 Psc Ab | |
| Mass | 1.7[10] M☉ |
| ψ1 Psc B | |
| Mass | 2.6[3] M☉ |
| Radius | 2.2[3] R☉ |
| Luminosity | 57[3] L☉ |
| Surface gravity (log g) | 4.04[3] cgs |
| Temperature | 10,694[3] K |
| Rotational velocity (v sin i) | 250[11] km/s |
| Age | 210[3] Myr |
| Other designations | |
| ψ1 Psc, 74 Psc, ADS 899 AB, CCDM J01057+2128 | |
| ψ1 Psc A: BD+20°156, HD 6456, HIP 5131, HR 310, SAO 74482 | |
| ψ1 Psc B: BD+20°157, HD 6457, HIP 5132, HR 311, SAO 74483 | |
| Database references | |
| SIMBAD | ψ1 Psc A |
| ψ1 Psc B | |
The two components of Psi1 Piscium are both A-type main-sequence stars.[4][6] The primary has an apparent magnitude of 5.273, while the secondary is slightly dimmer, with an apparent magnitude of 5.455.[2] The primary itself is a close binary, with two A-type stars that orbit each other every 14.44 years.[4]
Psi1 Piscium is moving through the Galaxy at a speed of 22.5 km/s relative to the Sun. Its projected Galactic orbit carries it between 22,800 and 24,300 light years from the center of the Galaxy.[12]
Naming
In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of refers to an asterism consisting of ψ1 Piscium, η Andromedae, 65 Piscium, ζ Andromedae, ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, τ Piscium, 91 Piscium, υ Piscium, φ Piscium and χ Piscium. Consequently, the Chinese name for ψ1 Piscium itself is 奎宿十六 (Kuí Sù shíliù, English: the Sixteenth Star of Legs.)[13]