Alpha Piscium
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Pisces |
| Right ascension | 02h 02m 02.81972s |
| Declination | +02° 45′ 49.5410″ |
| Apparent magnitude (V) | 3.82 (4.33 + 5.23) |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | kA0hA7 Sr + kA2hF2mF2 (IV) |
| Variable type | α2 CVn |
| Astrometry | |
| Proper motion (μ) | RA: +32.45 mas/yr Dec.: +0.04 mas/yr |
| Parallax (π) | 20.76±0.15 mas |
| Distance | 157.1 ± 1.1 ly (48.17±0.34 pc) |
| Absolute magnitude (MV) | +0.50 |
| Orbit | |
| Primary | α Psc A |
| Name | α Psc B |
| Period (P) | 2,822±215 yr |
| Semi-major axis (a) | 7.45±0.35″ |
| Eccentricity (e) | 0.4650±0.0145 |
| Inclination (i) | 113.01±2.45° |
| Longitude of the node (Ω) | 3.09±6.28° |
| Periastron epoch (T) | 2188.6 |
| Argument of periastron (ω) (secondary) | 150±6° |
| Orbit | |
| Primary | α Psc Ba |
| Name | α Psc Bb |
| Period (P) | 24.999428±0.000033 days |
| Semi-major axis (a) | (5.175±0.018)×10−3" (0.2493±0.0020 AU) |
| Eccentricity (e) | 0.6004±0.0018 |
| Inclination (i) | 65.2±0.4° |
| Longitude of the node (Ω) | 73.08±0.63° |
| Argument of periastron (ω) (primary) | 140.14±0.42° |
| Semi-amplitude (K1) (primary) | 61.17±0.35 km/s |
| Semi-amplitude (K2) (secondary) | 61.97±0.47 km/s |
| Details | |
| α Psc A | |
| Mass | 2.49±0.05 M☉ |
| Radius | 2.33±0.26 R☉ |
| Luminosity | 53.7+8.0 −6.9 L☉ |
| Surface gravity (log g) | 4.01±0.14 cgs |
| Temperature | 10,000±710 K |
| Rotation | 1.491±0.022 days |
| Rotational velocity (v sin i) | 81 km/s |
| Age | 330±150 Myr |
| α Psc Ba | |
| Mass | 1.668±0.033 M☉ |
| Radius | 1.76±0.41 R☉ |
| Surface gravity (log g) | 4.0 cgs |
| Temperature | 8,000 K |
| α Psc Bb | |
| Mass | 1.646±0.029 M☉ |
| Radius | 1.55±0.41 R☉ |
| Surface gravity (log g) | 4.0 cgs |
| Temperature | 8,000 K |
| Other designations | |
| Alrischa, Kaitain, Okda, Okdah, Syndesmos, α Psc, 113 Piscium, BD+02°317, FK5 28, HIP 9487, SAO 110291, WDS J02020+0246AB | |
| α Psc A: HD 12447, HR 596 | |
| α Psc B: HD 12446, HR 595 | |
| Database references | |
| SIMBAD | α Psc |
| α Psc A | |
| α Psc B | |
Alpha Piscium (α Piscium) is a triple star system in the equatorial constellation of Pisces. Based upon dynamical parallax measurements, it is about 157 light-years from the Solar System.
The three components are designated Alpha Piscium A (officially named Alrescha /ælˈriːʃə/, the traditional name of the system), Ba and Bb.