title: 24 Boötis
text: # 24 Boötis
  
  24 Boötis or g Boötis is a single, yellow-hued star in the constellation Boötes. It is faintly visible to the naked eye with an apparent visual magnitude of +5.59. Based upon an annual parallax shift of 10.00 mas, 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. 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. An extrasolar planet was discovered orbiting this star in 2018.
  
  This is an evolving red giant star with a stellar classification of G4 III-IV Fe-1, 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.
  
  ## Planetary system
  
  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
  
  The 24 Boötis planetary system :
  
  | Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
  | - | - | - | - | - | - | - |
  | b | ≥0.91+0.13 −0.10 $M_J$ | 0.190+0.012 −0.009 | 30.3506+0.0078 −0.0077 | 0.042+0.048 −0.029 | — | — |
  