Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Pisces |
Right ascension | 23h 27m 58.09529s [1] |
Declination | +6° 22′ 44.3720″ [1] |
Apparent magnitude (V) | 4.27 [2] |
Characteristics | |
Spectral type | K1 III [2] |
U−B color index | +1.00 |
B−V color index | +1.062 [2] |
Astrometry | |
Radial velocity (Rv) | +6.05±0.19 [2] km/s |
Proper motion (μ) |
RA: −123.83
[1]
mas/
yr Dec.: −43.26 [1] mas/ yr |
Parallax (π) | 21.96 ± 0.25 mas [1] |
Distance | 149 ± 2
ly (45.5 ± 0.5 pc) |
Absolute magnitude (MV) | +0.83 [2] |
Details | |
Mass | 1.58 [3] M☉ |
Radius | 11 [4] R☉ |
Luminosity | 51.3 [4] L☉ |
Surface gravity (log g) | 2.70 [5] cgs |
Temperature | 4,684±23 [3] K |
Metallicity [Fe/H] | 0.06 [5] dex |
Rotational velocity (v sin i) | 3.1 [4] km/s |
Age | 2.45 [3] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Theta Piscium, Latinized from θ Piscium, is a single, [7] orange-hued star in the zodiac constellation of Pisces, the fish. The annual parallax shift of this star was measured during the Hipparcos mission as 21.96 mas, [1] which yields a distance estimate of about 149 light years. It is a faint star but visible to the naked eye with an apparent visual magnitude of 4.27. [2] The star is moving away from the Sun with a radial velocity of +6 km/s. [2]
At the estimated age of 2.5 billion years, [3] this is an aging giant star with a stellar classification of K1 III, [2] which means it has exhausted the supply of hydrogen at its core. It is a red clump star, indicating it is on the horizontal branch of its evolution and is generating energy through helium fusion at its core. [5] Theta Piscium has 158% [3] of the Sun's mass and its outer atmosphere has swollen to about 11 [4] times the girth of the Sun. It is brighter yet cooler than the Sun, radiating 51.3 [4] times the Sun's luminosity from its enlarged photosphere at an effective temperature of about 4,684 K. [3]
In Chinese, 霹靂 (Pī Lì), meaning Thunderbolt, refers to an asterism consisting of refers to an asterism consisting of θ Piscium, β Piscium, γ Piscium, ι Piscium and ω Piscium. Consequently, the Chinese name for θ Piscium itself is 霹靂三 (Pī Lì sān, English: the Third Star of Thunderbolt.) [8]
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Pisces |
Right ascension | 23h 27m 58.09529s [1] |
Declination | +6° 22′ 44.3720″ [1] |
Apparent magnitude (V) | 4.27 [2] |
Characteristics | |
Spectral type | K1 III [2] |
U−B color index | +1.00 |
B−V color index | +1.062 [2] |
Astrometry | |
Radial velocity (Rv) | +6.05±0.19 [2] km/s |
Proper motion (μ) |
RA: −123.83
[1]
mas/
yr Dec.: −43.26 [1] mas/ yr |
Parallax (π) | 21.96 ± 0.25 mas [1] |
Distance | 149 ± 2
ly (45.5 ± 0.5 pc) |
Absolute magnitude (MV) | +0.83 [2] |
Details | |
Mass | 1.58 [3] M☉ |
Radius | 11 [4] R☉ |
Luminosity | 51.3 [4] L☉ |
Surface gravity (log g) | 2.70 [5] cgs |
Temperature | 4,684±23 [3] K |
Metallicity [Fe/H] | 0.06 [5] dex |
Rotational velocity (v sin i) | 3.1 [4] km/s |
Age | 2.45 [3] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Theta Piscium, Latinized from θ Piscium, is a single, [7] orange-hued star in the zodiac constellation of Pisces, the fish. The annual parallax shift of this star was measured during the Hipparcos mission as 21.96 mas, [1] which yields a distance estimate of about 149 light years. It is a faint star but visible to the naked eye with an apparent visual magnitude of 4.27. [2] The star is moving away from the Sun with a radial velocity of +6 km/s. [2]
At the estimated age of 2.5 billion years, [3] this is an aging giant star with a stellar classification of K1 III, [2] which means it has exhausted the supply of hydrogen at its core. It is a red clump star, indicating it is on the horizontal branch of its evolution and is generating energy through helium fusion at its core. [5] Theta Piscium has 158% [3] of the Sun's mass and its outer atmosphere has swollen to about 11 [4] times the girth of the Sun. It is brighter yet cooler than the Sun, radiating 51.3 [4] times the Sun's luminosity from its enlarged photosphere at an effective temperature of about 4,684 K. [3]
In Chinese, 霹靂 (Pī Lì), meaning Thunderbolt, refers to an asterism consisting of refers to an asterism consisting of θ Piscium, β Piscium, γ Piscium, ι Piscium and ω Piscium. Consequently, the Chinese name for θ Piscium itself is 霹靂三 (Pī Lì sān, English: the Third Star of Thunderbolt.) [8]