HD 145457
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Corona Borealis |
| Right ascension | 16h 10m 03.91440s |
| Declination | +26° 44′ 33.8932″ |
| Apparent magnitude (V) | 6.57 |
| Characteristics | |
| Evolutionary stage | red clump |
| Spectral type | K0 III |
| B−V color index | +1.037±0.005 |
| Astrometry | |
| Radial velocity (Rv) | −3.25±0.12 km/s |
| Proper motion (μ) | RA: −18.354 mas/yr Dec.: +36.856 mas/yr |
| Parallax (π) | 7.3867±0.0153 mas |
| Distance | 441.5 ± 0.9 ly (135.4 ± 0.3 pc) |
| Absolute magnitude (MV) | 1.09 |
| Details | |
| Mass | 1.57±0.46 M☉ |
| Radius | 10.49+0.13 −0.41 R☉ |
| Luminosity | 49.97±0.27 L☉ |
| Surface gravity (log g) | 2.72±0.11 cgs |
| Temperature | 4,738+95 −28 K |
| Metallicity [Fe/H] | −0.177 dex |
| Age | 5.2 Gyr |
| Other designations | |
| BD+27°2595, HD 145457, HIP 79219, SAO 84223 | |
| 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, as determined through parallax measurements. It has been formally named Kamuy by the IAU, after a spiritual or divine being in Ainu mythology. With an apparent magnitude of 6.57, 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.
HD 145457 is an aging giant star with a stellar classification of K0 III 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. With an age of 5.2 billion years old, it is around 1.57 times as massive as the Sun 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.
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.