Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Corona Borealis |
Right ascension | 16h 10m 03.91440s [1] |
Declination | +26° 44′ 33.8932″ [1] |
Apparent magnitude (V) | 6.57 [2] |
Characteristics | |
Evolutionary stage | Giant [3] |
Spectral type | K0 III [4] |
B−V color index | +1.037±0.005 [2] |
Astrometry | |
Radial velocity (Rv) | −3.25±0.12 [1] km/s |
Proper motion (μ) |
RA: −18.354
mas/
yr
[1] Dec.: +36.856 mas/ yr [1] |
Parallax (π) | 7.3867 ± 0.0153 mas [1] |
Distance | 441.5 ± 0.9
ly (135.4 ± 0.3 pc) |
Absolute magnitude (MV) | 1.09 [2] |
Details | |
Mass | 1.57±0.46 [3] M☉ |
Radius | 10.49+0.13 −0.41 [5] R☉ |
Luminosity | 49.97±0.27 [5] L☉ |
Surface gravity (log g) | 2.72±0.11 [3] cgs |
Temperature | 4,738+95 −28 [5] K |
Metallicity [Fe/H] | −0.177 [6] dex |
Age | 5.2 [6] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
HD 145457 is a star located in the northern constellation of Corona Borealis (The Northern Crown) at a distance of around 442 light-years from the Sun, [1] as determined through parallax measurements. It has been formally named Kamuy by the IAU, [8] after a spiritual or divine being in Ainu mythology. With an apparent magnitude of 6.57, [9] it is barely visible to the unaided eye on dark nights clear of light pollution. It is drifting closer to the Sun with a radial velocity of −3.2 km/s. [1]
HD 145457 is an aging giant star with a stellar classification of K0 III [4] that has cooled and expanded off the main sequence after exhausting its core hydrogen supply. With the assumption that it is a helium-burning object, the properties of HD 145457 can be derived by comparison with evolutionary tracks. [10] With an age of 5.2 billion years old, [6] it is around 1.57 times as massive as the Sun [3] and has swollen to around 10 times its diameter. It is radiating 50 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,738 K. [5]
It is a lithium-rich giant, unusual since lithium is rapidly destroyed once a star becomes a red giant. One explanation for the excess lithium in these stars has been a recent engulfment of a planet, but it is now thought more likely to be due to nucleosynthesis in the star. It is generally assumed that these lithium-rich giants are members of the red clump, core helium burning stars at the cool end of the horizontal branch. [11]
HD 145457 has an exoplanetary companion called HD 145457 b discovered in 2010. 2.9 times as massive as Jupiter, it orbits about every 176 days with an orbital eccentricity of 0.112±3.1. Its semimajor axis is 0.76 AU. HD 145457 b was discovered by precise Doppler measurements with the Subaru Telescope. [9]
As part of the IAU NameExoWorlds project in 2019, HD 145457 b has been formally named Chura. The name was selected by Japan. Chura is a word in the Ryukyuan/ Okinawan language meaning natural beauty. [8]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥2.794+0.132 −0.117 MJ |
0.762±0.001 | 176.13+0.18 −0.20 |
0.111+0.039 −0.040 |
— | — |
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Corona Borealis |
Right ascension | 16h 10m 03.91440s [1] |
Declination | +26° 44′ 33.8932″ [1] |
Apparent magnitude (V) | 6.57 [2] |
Characteristics | |
Evolutionary stage | Giant [3] |
Spectral type | K0 III [4] |
B−V color index | +1.037±0.005 [2] |
Astrometry | |
Radial velocity (Rv) | −3.25±0.12 [1] km/s |
Proper motion (μ) |
RA: −18.354
mas/
yr
[1] Dec.: +36.856 mas/ yr [1] |
Parallax (π) | 7.3867 ± 0.0153 mas [1] |
Distance | 441.5 ± 0.9
ly (135.4 ± 0.3 pc) |
Absolute magnitude (MV) | 1.09 [2] |
Details | |
Mass | 1.57±0.46 [3] M☉ |
Radius | 10.49+0.13 −0.41 [5] R☉ |
Luminosity | 49.97±0.27 [5] L☉ |
Surface gravity (log g) | 2.72±0.11 [3] cgs |
Temperature | 4,738+95 −28 [5] K |
Metallicity [Fe/H] | −0.177 [6] dex |
Age | 5.2 [6] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
HD 145457 is a star located in the northern constellation of Corona Borealis (The Northern Crown) at a distance of around 442 light-years from the Sun, [1] as determined through parallax measurements. It has been formally named Kamuy by the IAU, [8] after a spiritual or divine being in Ainu mythology. With an apparent magnitude of 6.57, [9] it is barely visible to the unaided eye on dark nights clear of light pollution. It is drifting closer to the Sun with a radial velocity of −3.2 km/s. [1]
HD 145457 is an aging giant star with a stellar classification of K0 III [4] that has cooled and expanded off the main sequence after exhausting its core hydrogen supply. With the assumption that it is a helium-burning object, the properties of HD 145457 can be derived by comparison with evolutionary tracks. [10] With an age of 5.2 billion years old, [6] it is around 1.57 times as massive as the Sun [3] and has swollen to around 10 times its diameter. It is radiating 50 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,738 K. [5]
It is a lithium-rich giant, unusual since lithium is rapidly destroyed once a star becomes a red giant. One explanation for the excess lithium in these stars has been a recent engulfment of a planet, but it is now thought more likely to be due to nucleosynthesis in the star. It is generally assumed that these lithium-rich giants are members of the red clump, core helium burning stars at the cool end of the horizontal branch. [11]
HD 145457 has an exoplanetary companion called HD 145457 b discovered in 2010. 2.9 times as massive as Jupiter, it orbits about every 176 days with an orbital eccentricity of 0.112±3.1. Its semimajor axis is 0.76 AU. HD 145457 b was discovered by precise Doppler measurements with the Subaru Telescope. [9]
As part of the IAU NameExoWorlds project in 2019, HD 145457 b has been formally named Chura. The name was selected by Japan. Chura is a word in the Ryukyuan/ Okinawan language meaning natural beauty. [8]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥2.794+0.132 −0.117 MJ |
0.762±0.001 | 176.13+0.18 −0.20 |
0.111+0.039 −0.040 |
— | — |