Chi Boötis

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Chi Boötis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Boötes
Right ascension  15h 14m 29.15853s[1]
Declination +29° 09′ 51.4577″[1]
Apparent magnitude (V) +5.3074±0.0005[1]
Spectral type A2 V[2]
U−B color index +0.08[3]
B−V color index +0.02[3]
Radial velocity (Rv)−16.0±0.8[4] km/s
Proper motion (μ) RA: −69.84[1] mas/yr
Dec.: +27.94[1] mas/yr
Parallax (π)12.92 ± 0.28[1] mas
Distance252 ± 5 ly
(77 ± 2 pc)
Absolute magnitude (MV)+0.84[5]
Mass2.09[6] M
Radius2.24[7] R
Luminosity36.8[8] L
Surface gravity (log g)3.96±0.14[6] cgs
Temperature9,268±315[6] K
Rotational velocity (v sin i)84[6] km/s
Age340[6] Myr
Other designations
χ Boo, 48 Boötis, BD+29° 2640, FK5 3204, GC 20495, HD 135502, HIP 74596, HR 5676, SAO 83729[9]
Database references

Chi Boötis, Latinized as χ Boötis, is a single,[10] white-hued star in the constellation Boötes. It is faintly visible to the naked eye with an apparent visual magnitude of +5.3.[1] Based upon an annual parallax shift of 12.92 mas as seen from the Earth, it is located about 252 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −16 km/s.[4]

This is an A-type main-sequence star with a stellar classification of A2 V,[2] which indicates it is generating energy via hydrogen fusion at its core. It is about 340[6] million years old with a projected rotational velocity of 84[6] km/s. The star has double the mass of the Sun,[6] 2.24 times the Sun's radius,[7] and is emitting 37[8] times the Sun's luminosity from its photosphere at an effective temperature of around 9,268 K.[6] It displays an infrared excess at an emission temperature of 65 K, indicating there is a circumstellar disk of dust orbiting the star at a distance of around 123 AU.[7]


  1. ^ a b c d e f g van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
  3. ^ a b Osawa, Kiyoteru (1959), "Spectral Classification of 533 B8-A2 Stars and the Mean Absolute Magnitude of A0 V Stars", Astrophysical Journal, 130: 159, Bibcode:1959ApJ...130..159O, doi:10.1086/146706.
  4. ^ a b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. ^ 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.
  6. ^ a b c d e f g h i David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  7. ^ a b c Rhee, Joseph H.; et al. (May 2007), "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs", The Astrophysical Journal, 660 (2): 1556–1571, arXiv:astro-ph/0609555, Bibcode:2007ApJ...660.1556R, doi:10.1086/509912.
  8. ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  9. ^ "chi Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-09.
  10. ^ Rodriguez, David R.; Zuckerman, B. (February 2012), "Binaries among Debris Disk Stars", The Astrophysical Journal, 745 (2): 147, arXiv:1111.5618, Bibcode:2012ApJ...745..147R, doi:10.1088/0004-637X/745/2/147.


  • "chi Boo", Aladin previewer, Centre de Données astronomiques de Strasbourg, retrieved 2017-09-11.