Chi Boötis

Chi Boötis, Latinised as χ Boötis, is a single,[11] white-hued star in the northern constellation Boötes, near the eastern constellation border with Corona Borealis. It is faintly visible to the naked eye with an apparent visual magnitude of +5.3.[2] Based upon an annual parallax shift of 13.0 mas as seen from the Earth, it is located about 251 light-years from the Sun. The star is moving closer to the Sun with a radial velocity of −16 km/s.[5]

Chi Boötis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Boötes
Right ascension 15h 14m 29.15897s[1]
Declination +29° 09′ 51.4630″[1]
Apparent magnitude (V) +5.3074±0.0005[2]
Characteristics
Spectral type A2 V[3]
U−B color index +0.08[4]
B−V color index +0.02[4]
Astrometry
Radial velocity (Rv)−16.0±0.8[5] km/s
Proper motion (μ) RA: −69.688[1] mas/yr
Dec.: +28.940[1] mas/yr
Parallax (π)13.0060 ± 0.1089 mas[2]
Distance251 ± 2 ly
(76.9 ± 0.6 pc)
Absolute magnitude (MV)+0.84[6]
Details
Mass2.09[7] M☉
Radius2.24[8] R☉
Luminosity36.8[9] L☉
Surface gravity (log g)3.96±0.14[7] cgs
Temperature9,268±315[7] K
Rotational velocity (v sin i)84[7] km/s
Age340[7] Myr
Other designations
χ Boo, 48 Boötis, BD+29° 2640, FK5 3204, GC 20495, HD 135502, HIP 74596, HR 5676, SAO 83729[10]
Database references
SIMBADdata

This is an A-type main-sequence star with a stellar classification of A2 V,[3] which indicates it is generating energy via hydrogen fusion at its core. It is about 340[7] million years old with a projected rotational velocity of 84[7] km/s. The star has double the mass of the Sun,[7] 2.24 times the Sun's radius,[8] and is emitting 37[9] times the Sun's luminosity from its photosphere at an effective temperature of around 9,268 K.[7] 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.[8]

References
  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.
  2. 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, S2CID 18759600.
  3. 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.
  4. 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.
  5. 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, S2CID 59451347, A61.
  6. 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, S2CID 119257644.
  7. 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, S2CID 33401607.
  8. 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, S2CID 11879505.
  9. 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, S2CID 118665352.
  10. "chi Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-09.{{cite web}}: CS1 maint: postscript (link)
  11. 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, S2CID 73681879.
  • "chi Boo", Aladin previewer, Centre de Données astronomiques de Strasbourg, retrieved 2017-09-11.
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