Lambda Piscium
Star in the constellation Pisces
From Wikipedia, the free encyclopedia
Lambda Piscium, Latinized from λ Piscium, is a solitary,[8] white-hued star in the zodiac constellation of Pisces. With an apparent visual magnitude of 4.49,[2] it is visible to the naked eye, forming the southeast corner of the "Circlet" asterism in Pisces. Based upon a measured annual parallax shift of 30.59 mas as seen from Earth,[1] it is located 107 light years distant from the Sun. Lambda Piscium is a member of the Ursa Major Stream, lying among the outer parts, or corona, of this moving group of stars that roughly follow a common heading through space.[9]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Pisces |
| Right ascension | 23h 42m 02.80612s[1] |
| Declination | +01° 46â² 48.1484â³[1] |
| Apparent magnitude (V) | 4.49[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A7 V[4] |
| UâB color index | +0.09[2] |
| BâV color index | +0.20[2] |
| Astrometry | |
| Radial velocity (Rv) | 6.7[5] km/s |
| Proper motion (μ) | RA: â129.70[1] mas/yr Dec.: â154.80[1] mas/yr |
| Parallax (Ï) | 30.59±0.19 mas[1] |
| Distance | 106.6 ± 0.7 ly (32.7 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.92[6] |
| Details | |
| Mass | 1.806[4] Mâ |
| Radius | 2.0403±0.0451[4] Râ |
| Luminosity | 13.3897±0.1692[4] Lâ |
| Surface gravity (log g) | 4.08[5] cgs |
| Temperature | 7,734±80[4] K |
| Metallicity [Fe/H] | 0.02[5] dex |
| Rotational velocity (v sin i) | 70[3] km/s |
| Age | 583±20[3] Myr |
| Other designations | |
| λ Psc, 18 Piscium, BD+00°5037, FK5 1620, HD 222603, HIP 116928, HR 8984, SAO 128336[7] | |
| Database references | |
| SIMBAD | data |
This well-studied star[5] has a stellar classification A7 V,[4] indicating it is an A-type main-sequence star that is generating energy through hydrogen fusion at its core. It has 1.8 times the mass of the Sun and double the Sun's radius. The star is radiating 13.3 times the Sun's luminosity from its photosphere at an effective temperature of 7,734 K.[4] Lambda Piscium is around 583 million years old and is spinning with a projected rotational velocity of 70 km/s.[3]
Naming
In Chinese, é²é¨ (Yún YÇ), meaning Cloud and Rain, refers to an asterism consisting of λ Piscium, κ Piscium, 12 Piscium and 21 Piscium. Consequently, the Chinese name for λ Piscium itself is é²é¨å (Yún YÇ sì, English: the Fourth Star of Cloud and Rain.)[10]