6 Boötis

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6 Boötis
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Boötes
Right ascension  13h 49m 42.82223s[1]
Declination +21° 15′ 50.8580″[1]
Apparent magnitude (V) 4.92[2]
Spectral type K4 III[3] + M8 V[4]
B−V color index 1.432±0.013[2]
Radial velocity (Rv)−3.71±0.48[1] km/s
Proper motion (μ) RA: +33.773[1] mas/yr
Dec.: +10.842[1] mas/yr
Parallax (π)7.1527 ± 0.3659[1] mas
Distance460 ± 20 ly
(140 ± 7 pc)
Absolute magnitude (MV)−0.49[2]
Period (P)944±8 d
Eccentricity (e)0.41±0.09
Periastron epoch (T)2,444,739.5±31.0 JD
Argument of periastron (ω)
Semi-amplitude (K1)
1.19±0.15 km/s
Radius38[5] R
Luminosity430.124[1] L
Surface gravity (log g)1.910[6] cgs
Temperature4,050[6] K
Metallicity [Fe/H]−0.24[6] dex
Rotational velocity (v sin i)2.0[7] km/s
Other designations
e Boötis, 53 Cam, BD+21°2578, FK5 3098, GC 18683, HD 120539, HIP 67480, HR 5201, SAO 83015[8]
Database references

6 Boötis is a binary star[4] system in the northern constellation of Boötes,[8] located around 460 light years away from the Sun.[1] It has the Bayer designation e Boötis; 6 Boötis is the Flamsteed designation.[8] The system is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.92.[2] It is moving closer to the Earth with a heliocentric radial velocity of −3 km/s.[2]

This is a single-lined spectroscopic binary system with an orbital period of 2.58 years and an eccentricity of 0.4.[4] The visible component is an evolved giant star with a stellar classification of K4 III,[3] its measured angular diameter is 2.53±0.12 mas.[9] At the estimated distance of the star, this yields a physical size of about 38 times the radius of the Sun;[5] the star is radiating 430[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,050 K.[6] Its companion is probably a low mass red dwarf of around class M8 V.[4]


  1. ^ a b c d e f g h i 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. ^ a b c d e 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.
  3. ^ a b Yoss, K. M.; Griffin, R. F. (September 1997), "Radial Velocities and DDO, BV Photometry of Henry Draper G5-M Stars Near the North Galactic Pole", Journal of Astrophysics and Astronomy, 18: 161, Bibcode:1997JApA...18..161Y, doi:10.1007/BF02714877.
  4. ^ a b c d e Griffin, R. F. (June 1985), "Spectroscopic binaries near the North Galactic Pole. Paper 12 : 6 Bootis.", Journal of Astrophysics and Astronomy, 6: 77–83, Bibcode:1985JApA....6...77G, doi:10.1007/BF02715079.
  5. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
  6. ^ a b c d McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527
  7. ^ De Medeiros, J. R.; et al. (October 2002), "The Rotation of Binary Systems with Evolved Components", The Astrophysical Journal, 578 (2): 943–950, arXiv:astro-ph/0207288, Bibcode:2002ApJ...578..943D, doi:10.1086/342613.
  8. ^ a b c "6 Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-04-23.
  9. ^ Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.