24 Boötis

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24 Boötis
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension  14h 28m 37.8130s[1]
Declination +49° 50′ 41.461″[1]
Apparent magnitude (V) +5.59[2]
Spectral type G4 III-IV Fe-1[3]
B−V color index 0.85±0.02[2]
Radial velocity (Rv)−8.116±0.024[2] km/s
Proper motion (μ) RA: −304.035[1] mas/yr
Dec.: -46.861[1] mas/yr
Parallax (π)10.00 ± 0.25[1] mas
Distance326 ± 8 ly
(100 ± 3 pc)
Absolute magnitude (MV)+0.59[2]
Mass0.97±0.06 M
Radius12.24±1.16 R
Surface gravity (log g)2.17±0.02 cgs
Temperature4,863±5 K
Metallicity [Fe/H]−0.77±0.01 dex
Rotational velocity (v sin i)2.57±0.73 km/s
Other designations
g Boötis, 24 Boo, BD+50° 2084, GC 19532, HD 127243, HIP 70791, HR 5420, SAO 29165[4]
Database references

24 Boötis or g Boötis is a single,[5] yellow-hued star in the constellation Boötes. It is faintly visible to the naked eye with an apparent visual magnitude of +5.59.[2] Based upon an annual parallax shift of 10.00 mas,[1] it is located around 326 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −8 km/s,[2] it is a thick disk star with a high galactic space velocity and an orbital eccentricity of 0.47±0.01 that carries it as close as 3.30±0.05 kpc to the galactic center, and as far away as 9.15±0.02 kpc.[6] An extrasolar planet was discovered orbiting this star in 2018.[7]

This is an evolving red giant[6] star with a stellar classification of G4 III-IV Fe-1,[3] with the notation indicating the spectrum shows blended characteristics of a subgiant and giant star with an underabundance of iron. At the age of around 7 billion years old, it has 0.97 times the mass of the Sun but has expanded to 12 times the Sun's radius. The star is radiating 61.7 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,863 K.[2]

Planetary system[edit]

24 Boötis b was discovered by Takuya Takarada and collaborators using the Doppler Spectroscopy method, during the Okayama Planet Search radial velocity survey of G and K giants at Okayama Astrophysical Observatory. The preprint announcing the discovery was published on the arXiv eprint repository on April 11, 2018[7]

The 24 Boötis planetary system[7]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b ≥0.91+0.13


  1. ^ a b c d e f 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.
  2. ^ a b c d e f g h Niedzielski, A.; et al. (January 2016), "The Penn State - Toruń Centre for Astronomy Planet Search stars", Astronomy & Astrophysics, 585: 14, arXiv:1407.4956, Bibcode:2016A&A...585A..73N, doi:10.1051/0004-6361/201527362, A73
  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. ^ "g Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-02-09.
  5. ^ 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.
  6. ^ a b Pakhomov, Yu. V. (February 2012), "Chemical composition of the atmospheres of red giants with high space velocities", Astronomy Letters, 38 (2): 101−116, arXiv:1312.3195, Bibcode:2012AstL...38..101P, doi:10.1134/S1063773712020053.
  7. ^ a b c Takarada, Takuya; et al. (2018). "Planets around the evolved stars 24 Booties and γ Libra: A 30d-period planet and a double giant-planet system in possible 7:3 MMR". arXiv:1804.04008 [astro-ph.EP].

External links[edit]