HD 145457
Star in the constellation Corona Borealis / From Wikipedia, the free encyclopedia
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]
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 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]