CP Boötis

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CP Boötis
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension 14h 33m 20.26330s[1]
Declination +36° 57′ 32.4483″[1]
Apparent magnitude (V) 6.40[2]
Evolutionary stage subgiant[3]
Spectral type F8 IVw[4]
U−B color index 0.07[2]
B−V color index 0.51[2]
Variable type δ Sct[5]
Radial velocity (Rv)+5.9[6] km/s
Proper motion (μ) RA: +2.694[1] mas/yr
Dec.: −73.096[1] mas/yr
Parallax (π)12.9135 ± 0.0244[1] mas
Distance252.6 ± 0.5 ly
(77.4 ± 0.1 pc)
Absolute magnitude (MV)2.05[2]
Mass1.77[6] M
[7] L
Surface gravity (log g)3.67[6] cgs
Temperature6,276[6] K
Metallicity [Fe/H]0.25[6] dex
Rotational velocity (v sin i)5.7[3] km/s
Age1.70[6] Gyr
Other designations
CP Boo, BD+37° 2545, HD 127986, HIP 71168, HR 5441, SAO 64212[8]
Database references

CP Boötis is a yellow-white hued star in the northern constellation of Boötes. With a baseline apparent visual magnitude of 6.40,[2] it is at or near the lower limit for visibility with the typical naked eye in good viewing conditions. The distance to this star can be estimated from its annual parallax shift of 12.91 mas,[1] which yields a range of 252.6 light years. It is moving further away with a heliocentric radial velocity of +5.9 km/s.[6]

This is an F-type subgiant star with a stellar classification of F8 IVw,[4] which indicates it has nearly consumed the hydrogen at its core and is now evolving into a giant star. It is a low amplitude Delta Scuti variable[9] that varies by 0.02 magnitude.[10] At the age of 1.7[6] billion years it is spinning with a projected rotational velocity of 5.7 km/s.[3] The star has 1.77[6] times the mass of the Sun and is radiating 12[7] times the Sun's luminosity from its photosphere at an effective temperature of 6,276 K.[6]


  1. ^ a b c d e f 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:1804.09365Freely accessible. Bibcode:2018A&A...616A...1GFreely accessible. doi:10.1051/0004-6361/201833051Freely accessible. 
  2. ^ a b c d e Karatas, Y.; Schuster, W. J. (October 2006), "Metallicity and absolute magnitude calibrations for UBV photometry", Monthly Notices of the Royal Astronomical Society, 371 (4): 1793–1812, Bibcode:2006MNRAS.371.1793K, doi:10.1111/j.1365-2966.2006.10800.x. 
  3. ^ a b c Lèbre, A.; et al. (1999), "Lithium and rotation on the subgiant branch. I. Observations and spectral analysis", Astronomy and Astrophysics, 345: 936, Bibcode:1999A&A...345..936L. 
  4. ^ a b Barry, Don C. (January 1970), "Spectral classification of A & F stars", Astrophysical Journal Supplement, 19: 281, Bibcode:1970ApJS...19..281B, doi:10.1086/190209 
  5. ^ Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61: 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085. 
    See: CP Boo
  6. ^ a b c d e f g h i j Casagrande, L.; et al. (June 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:1103.4651Freely accessible, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276. 
  7. ^ a b do Nascimento, J. D., Jr.; et al. (May 2000), "Lithium and rotation on the subgiant branch. II. Theoretical analysis of observations", Astronomy and Astrophysics, 357: 931–937, arXiv:astro-ph/0003010Freely accessible, Bibcode:2000A&A...357..931D. 
  8. ^ "HD 127986". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 August 2018. 
  9. ^ Galeev, A. I.; et al. (November 2012), "Chemical composition of δ Scuti stars: 1. AO CVn, CP Boo, KW Aur", Astronomy Reports, 56 (11): 850–866, Bibcode:2012ARep...56..850G, doi:10.1134/S1063772912110029 
  10. ^ Watson, Christopher (January 4, 2010), "CP Boötis", AAVSO Website, American Association of Variable Star Observers, retrieved 3 August 2014. 

External links[edit]