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HD 145457

HD 145457 is a star located in the northern constellationofCorona 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 beinginAinu 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 eccentricityof0.112±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]