40 Boötis

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40 Boötis
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension  14h 59m 36.94745s[1]
Declination +39° 15′ 55.1994″[1]
Apparent magnitude (V) 5.64[2]
Evolutionary stage giant[3]
Spectral type F1 III–IV[4]
B−V color index 0.336±0.004[2]
Radial velocity (Rv)+12.3±0.7[5] km/s
Proper motion (μ) RA: −32.109[1] mas/yr
Dec.: 41.246[1] mas/yr
Parallax (π)19.5911 ± 0.0702[1] mas
Distance166.5 ± 0.6 ly
(51.0 ± 0.2 pc)
Absolute magnitude (MV)2.08[2]
Mass1.47[6] M
[1] R
Luminosity11.585±0.054[1] L
Surface gravity (log g)3.88[6] cgs
Temperature7,070±240[6] K
Metallicity [Fe/H]−0.29[5] dex
Rotational velocity (v sin i)72.5[3] km/s
Age1.166[6] Gyr
Other designations
40 Boo, BD+39°2820, FK5 3182, HD 132772, HIP 73369, HR 5588, SAO 64449[7]
Database references

40 Boötis is a single[8] star located 166.5 light years away from the Sun in the northern constellation of Boötes. It is visible to the naked eye as a dim, yellow-white hued star with an apparent visual magnitude of 5.64.[2] The star is moving away from the Earth with a heliocentric radial velocity of +12 km/s.[5]

The Hipparcos catalogue (1997) lists a stellar classification of F1 III–IV,[9] matching the luminosity class of an aging star that is evolving into a giant.[3] Earlier, Cowley and Bidelman (1979) listed a class of F2 III,[10] while Sato and Kuji (1990) found a main sequence class of F0V.[11] It is around 1.2[6] billion years old with a relatively high rotation rate, showing a projected rotational velocity of 72.5 km/s.[3] The star has 1.5[6] times the mass of the Sun and 2.4[1] times the Sun's radius. It is radiating 11.6[1] times the luminosity of the Sun from its photosphere at an effective temperature of 7,070 K.[6]


  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 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 c d Schröder, C.; et al. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377.[permanent dead link]
  4. ^ Boro Saikia, S.; et al. (2018), "Chromospheric activity catalogue of 4454 cool stars. Questioning the active branch of stellar activity cycles", Astronomy and Astrophysics, 616: A108, arXiv:1803.11123, Bibcode:2018A&A...616A.108B, doi:10.1051/0004-6361/201629518.
  5. ^ a b c Casagrande, L.; et al. (2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy and Astrophysics, 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.
  6. ^ a b c d e f g 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. ^ "40 Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 12, 2019.
  8. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  9. ^ ESA (1997), The HIPPARCOS and TYCHO catalogues. Astrometric and photometric star catalogues derived from the ESA HIPPARCOS Space Astrometry Mission, 1200, Noordwijk, Netherlands: ESA Publications Division, Bibcode:1997ESASP1200.....E.
  10. ^ Cowley, A. P.; Bidelman, W. P. (February 1979), "MK spectral types for some F and G stars", Publications of the Astronomical Society of the Pacific, 91: 83–86, Bibcode:1979PASP...91...83C, doi:10.1086/130446.
  11. ^ Sato, K.; Kuji, S. (November 1990), "MK classification and photometry of stars used for time and latitude observations at Mizusawa and Washington", Astronomy and Astrophysics Supplement Series, 85 (3): 1069–1087, Bibcode:1990A&AS...85.1069S.