24 Boötis
Star in the constellation Boötes
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24 Boötis or g Boötis is a single,[6] 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 10.59 mas,[1] it is located around 308 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.[7] An extrasolar planet was discovered orbiting this star in 2018.[8]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Boötes |
| Right ascension | 14h 28m 37.81288s[1] |
| Declination | +49° 50′ 41.4615″[1] |
| Apparent magnitude (V) | +5.59[2] |
| Characteristics | |
| Spectral type | G4 III-IV Fe-1[3] |
| B−V color index | 0.85±0.02[2] |
| Astrometry | |
| Radial velocity (Rv) | −8.116±0.024[2] km/s |
| Proper motion (μ) | RA: −303.943 mas/yr[1] Dec.: −46.836 mas/yr[1] |
| Parallax (π) | 10.5895±0.0421 mas[1] |
| Distance | 308 ± 1 ly (94.4 ± 0.4 pc) |
| Absolute magnitude (MV) | +0.59[2] |
| Details[4] | |
| Mass | 1.46±0.15 M☉ |
| Radius | 10.045±0.098 R☉ |
| Luminosity | 54.97±0.90 L☉ |
| Surface gravity (log g) | 2.599±0.047 cgs |
| Temperature | 4,959±21 K |
| Metallicity [Fe/H] | −0.71±0.06 dex |
| Rotational velocity (v sin i) | 2.57±0.73[2] km/s |
| Other designations | |
| g Boötis, 24 Boo, BD+50°2084, GC 19532, HD 127243, HIP 70791, HR 5420, SAO 29165[5] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is an evolving red giant[7] 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. It has 1.46 times the mass of the Sun but has expanded to ten times the Sun's radius. The star is radiating 55 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,959 K.[4]
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.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | ≥0.7913+0.0063 −0.0062 MJ |
0.190865±0.000004 | 30.6106+0.0010 −0.0009 |
0.0545+0.0072 −0.0068 |
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