HD 145457

HD 145457
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Corona Borealis
Right ascension	16h 10m 03.91437s[1]
Declination	+26° 44′ 33.8937″[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)	−3.15±0.13[1] km/s
Proper motion (μ)	RA: −18.336[1] mas/yr ; Dec.: +36.824[1] mas/yr
Parallax (π)	7.3625 ± 0.0219[1] mas
Distance	443 ± 1 ly ; (135.8 ± 0.4 pc)
Absolute magnitude (MV)	1.09[2]
Details
Mass	1.57±0.46[3] M☉
Radius	10.49+0.13; −0.41[1] R☉
Luminosity	49.97±0.27[1] L☉
Surface gravity (log g)	2.72±0.11[3] cgs
Temperature	4,738+95; −28[1] K
Metallicity [Fe/H]	−0.06±0.05[3] dex
Age	9.30±0.13[3] Gyr
Other designations
	BD+27°2595, HD 145457, HIP 79219, SAO 84223[5]
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 443 light-years from the Sun,[1] as determined through parallax measurements. It has been formally named Kamuy by the IAU,[6] after a spiritual or divine being in Ainu mythology. With an apparent magnitude of 6.57,[7] 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]

This object 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. It is thought to be a red clump star, fusing helium in its core.[8] With an age of 9.3[3] billion years old, it is around 1.57[3] 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.[1]

Companion

HD 145457 has a 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.[7]

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.[6]

References

Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
Feuillet, Diane K.; et al. (2016). "Determining Ages of APOGEE Giants with Known Distances". The Astrophysical Journal. 817: 40. arXiv:1511.04088. Bibcode:2016ApJ...817...40F. doi:10.3847/0004-637X/817/1/40.
Heard, John Frederick (1956). "The radial velocities, spectral classes and photographic magnitudes of 1041 late-type stars". Publications of the David Dunlap Observatory. University of Toronto, Toronto, Canada: University of Toronto Press. 2 (4): 107–143. Bibcode:1956PDDO....2..107H.
"HD 145457". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-02-04.
"Japan". NameExoworlds. IAU. Retrieved 2019-12-30.
Sato, Bun'ei; et al. (2010). "Substellar Companions to Evolved Intermediate-Mass Stars: HD 145457 and HD 180314". Publications of the Astronomical Society of Japan. 62 (4): 1063–69. arXiv:1005.2860. Bibcode:2010PASJ...62.1063S. doi:10.1093/pasj/62.4.1063.
Kumar, Yerra Bharat; Reddy, Bacham E.; Lambert, David L. (2011). "Origin of Lithium Enrichment in K Giants". The Astrophysical Journal. 730 (1): L12. arXiv:1102.2299. Bibcode:2011ApJ...730L..12K. doi:10.1088/2041-8205/730/1/L12.

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[GaiaDR2-1] Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.

[Anderson2012-2] Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.

[Feuillet2016-3] Feuillet, Diane K.; et al. (2016). "Determining Ages of APOGEE Giants with Known Distances". The Astrophysical Journal. 817: 40. arXiv:1511.04088. Bibcode:2016ApJ...817...40F. doi:10.3847/0004-637X/817/1/40.

[Heard1956-4] Heard, John Frederick (1956). "The radial velocities, spectral classes and photographic magnitudes of 1041 late-type stars". Publications of the David Dunlap Observatory. University of Toronto, Toronto, Canada: University of Toronto Press. 2 (4): 107–143. Bibcode:1956PDDO....2..107H.

[SIMBAD-5] "HD 145457". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-02-04.

[IAU-6] "Japan". NameExoworlds. IAU. Retrieved 2019-12-30.

[sato_2010-7] Sato, Bun'ei; et al. (2010). "Substellar Companions to Evolved Intermediate-Mass Stars: HD 145457 and HD 180314". Publications of the Astronomical Society of Japan. 62 (4): 1063–69. arXiv:1005.2860. Bibcode:2010PASJ...62.1063S. doi:10.1093/pasj/62.4.1063.

[kumar2011-8] Kumar, Yerra Bharat; Reddy, Bacham E.; Lambert, David L. (2011). "Origin of Lithium Enrichment in K Giants". The Astrophysical Journal. 730 (1): L12. arXiv:1102.2299. Bibcode:2011ApJ...730L..12K. doi:10.1088/2041-8205/730/1/L12.