HD 145457

HD 145457 / Kamuy
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]
Distance441.5 ± 0.9 ly
(135.4 ± 0.3 pc)
Absolute magnitude (MV)1.09[2]
Details
Mass1.57±0.46[3] M☉
Radius10.49+0.13
−0.41[5] R☉
Luminosity49.97±0.27[5] L☉
Surface gravity (log g)2.72±0.11[3] cgs
Temperature4,738+95
−28[5] K
Metallicity [Fe/H]−0.177[6] dex
Age5.2[6] Gyr
Other designations
BD+27°2595, HD 145457, HIP 79219, SAO 84223[7]
Database references
SIMBADdata

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]

  1. ^ a b c d e f g Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Feuillet2016 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Heard1956 was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference ting2019 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference IAU was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference sato 2010 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference kumar2011 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference holanda2020 was invoked but never defined (see the help page).