Tau Piscium (τ Piscium) is an orange-hued star in the zodiac constellation of Pisces. With an apparent visual magnitude of +4.52,[2] it is a dim star but visible to the naked eye. Based upon an annual parallax shift of 19.32 mas as seen from Earth,[1] it is located around 169 light years from the Sun. It is most likely (96% chance) a member of the thin disk population.[5]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Pisces |
Right ascension | 01h 11m 39.63647s[1] |
Declination | +30° 05′ 22.6909″[1] |
Apparent magnitude (V) | +4.518[2] |
Characteristics | |
Spectral type | K0.5 IIIb[3] |
U−B color index | +1.016[2] |
B−V color index | +1.094[2] |
Astrometry | |
Radial velocity (Rv) | 36.36±0.34[4] km/s |
Proper motion (μ) | RA: +73.88[1] mas/yr Dec.: −38.30[1] mas/yr |
Parallax (π) | 19.32 ± 0.24 mas[1] |
Distance | 169 ± 2 ly (51.8 ± 0.6 pc) |
Absolute magnitude (MV) | +1.033[5] |
Details[4] | |
Mass | 1.69[6] M☉ |
Radius | 10 R☉ |
Luminosity | 44.7 L☉ |
Surface gravity (log g) | 2.6 cgs |
Temperature | 4,624±5 K |
Metallicity [Fe/H] | −0.04 dex |
Rotational velocity (v sin i) | 2.2 km/s |
Age | 2.27[4] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
This is an evolved K-type giant star with a stellar classification of K0.5 IIIb.[3] It is about 2.27[4] billion years and is a red clump star on the horizontal branch, which indicates it is generating energy through helium fusion at its core.[8] The star has 1.7[6] times the mass of the Sun and has expanded to about 10 times the Sun's radius.[4] It is radiating 45 times the Sun's luminosity from its photosphere at an effective temperature of 4,624 K.[4]
In Chinese, 奎宿 (Kuí Sù), meaning Legs, refers to an asterism consisting of τ Piscium, η Andromedae, 65 Piscium, ζ Andromedae, ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, σ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, the Chinese name for τ Piscium itself is 奎宿十一 (Kuí Sù shíyī, English: the Eleventh Star of Legs.)[9]
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