Psi Boötis

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Psi Boötis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Boötes
Right ascension 15h 04m 26.74234s[1]
Declination +26° 56′ 51.5399″[1]
Apparent magnitude (V) +4.55[2]
Spectral type K2 III[3]
U−B color index +1.34[2]
B−V color index +1.23[2]
Radial velocity (Rv) −25.72±0.18[4] km/s
Proper motion (μ) RA: −175.42[1] mas/yr
Dec.: −4.06[1] mas/yr
Parallax (π) 13.26 ± 0.26[1] mas
Distance 246 ± 5 ly
(75 ± 1 pc)
Absolute magnitude (MV) +0.16[5]
Mass 1.38[6] M
Radius 20[4] R
Luminosity 135[6] L
Surface gravity (log g) 2.2[4] cgs
Temperature 4,302±22[6] K
Metallicity [Fe/H] −0.35[4] dex
Rotational velocity (v sin i) 3.5[4] km/s
Age 4.16[6] Gyr
Other designations
Aulad al Nathlat[7], ψ Boo, 43 Boötis, BD+27° 2447, FK5 557, GC 20285, HD 133582, HIP 73745, HR 5616, SAO 83645[8]
Database references

Psi Boötis (ψ Boötis) is a single,[9] orange-hued star in the northern constellation of Boötes. It is a dim star that is visible to the naked eye with an apparent visual magnitude of +4.55.[2] Based upon an annual parallax shift of 13.26 mas as seen from the Earth, it is located about246 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.09 due to interstellar dust.[5] It is traversing the sky with a net proper motion of 0.176 arc seconds per year,[10] and has a radial velocity toward the Sun of −25.72 km/s.[4]

This star has a stellar classification of K2 III,[3] matching an evolved K-type giant star. It belongs to the so-called "red clump",[11] indicating that it is generating energy through helium fusion at its core. This star is about four[6] billion years old and is spinning with a projected rotational velocity of 3.5 km/s.[4] It has an estimated 1.38[6] times the mass of the Sun and has expanded to 20[4] times the Sun's radius. Psi Boötis radiating 135[6] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,302 km/s.[6]


This star, according to Assemani, with another in the right arm that may have been ε Boo (Izar), constituted the Arabs' Al Aulād al Nadhlāt, which he rendered filii altercationis (sons of contention); but the original signifies "the Low, or Mean, Little Ones".[12]

Al Aulād al Nadhlāt or Aulad al Nathlat was the title of this star in the catalogue of stars in Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars.[7]


  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J. 
  3. ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373. 
  4. ^ a b c d e f g h Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209. 
  5. ^ a b Famaey, B.; et al. (2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430: 165–186, arXiv:astro-ph/0409579Freely accessible, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272. 
  6. ^ a b c d e f g h Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 88, arXiv:1507.01466Freely accessible, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88. 
  7. ^ a b Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology. 
  8. ^ "psi Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-09. 
  9. ^ 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:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  10. ^ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal, 129 (3): 1483–1522, arXiv:astro-ph/0412070Freely accessible, Bibcode:2005AJ....129.1483L, doi:10.1086/427854. 
  11. ^ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329Freely accessible, Bibcode:2000ApJ...539..732A, doi:10.1086/309278. 
  12. ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 106. ISBN 0-486-21079-0. Retrieved 2010-12-12. 


  • Hoffleit; et al. (1991), "HR 5616", Bright Star Catalogue (5th Revised ed.), retrieved 2017-09-11. 
  • "psi Boo", Aladin previewer, Centre de Données astronomiques de Strasbourg, retrieved 2017-09-11.