HD 72659
Star in the constellation of Hydra
From Wikipedia, the free encyclopedia
HD 72659 is a star in the equatorial constellation of Hydra. With an apparent visual magnitude of 7.46,[1] its yellow-hued star is too faint to be viewed with the naked eye. Parallax measurements provide a distance estimate of 169.4 light years from the Sun, and it has an absolute magnitude of 3.98.[1] The star is drifting closer with a radial velocity of −18.2 km/s.[4]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra[1] |
| Right ascension | 08h 34m 03.18984s[2] |
| Declination | −01° 34′ 05.5822″[2] |
| Apparent magnitude (V) | 7.46[1] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G2V[3] |
| B−V color index | +0.612±0.015[1] |
| Astrometry | |
| Radial velocity (Rv) | −18.203+0.024 −0.029[4] km/s |
| Proper motion (μ) | RA: −112.313(26) mas/yr[2] Dec.: −96.386(18) mas/yr[2] |
| Parallax (π) | 19.2582±0.0271 mas[2] |
| Distance | 169.4 ± 0.2 ly (51.93 ± 0.07 pc) |
| Absolute magnitude (MV) | 3.98[1] |
| Details[4] | |
| Mass | 1.033±0.025 M☉ |
| Radius | 1.36±0.06 R☉ |
| Luminosity | 2.16±0.01[5] L☉ |
| Surface gravity (log g) | 4.19±0.02[5] cgs |
| Temperature | 5,929±61 K |
| Metallicity [Fe/H] | −0.02±0.06 dex |
| Rotational velocity (v sin i) | 1.6±0.9 km/s |
| Age | 8±1 Gyr |
| Other designations | |
| BD−01°2075, HD 72659, HIP 42030, SAO 136045, 2MASS J08340320-0134056, Gaia DR2 3073443760538892032[6] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is a Sun-like main sequence star with a stellar classification of G2V,[3] indicating that it is generating energy through core hydrogen fusion. It is older than the Sun with an age of about seven billion years,[5] and is spinning with a projected rotational velocity of 5.1 km/s.[7] The star has 7% greater mass than the Sun and a 38% larger radius. It is radiating more than double the Sun's luminosity from its photosphere at an effective temperature of 5,956 K.[5] The metallicity of the stellar atmosphere is similar to the Sun.[1]
Planetary system
An extrasolar planet was discovered orbiting this star in 2003 via the Doppler method.[8] This is a superjovian planet with an eccentric orbit, completing a lap around its host star every 9.9 years.[9] In 2022, the inclination and true mass of HD 72659 b were measured via astrometry, along with the detection of a second substellar companion, likely a brown dwarf.[10] The orbit of the brown dwarf lies in the so-called brown dwarf desert, regions with a deficit of brown dwarfs. The host star is very old and thus HD 72659 b and c can not be directly imaged, even with the most modern equipment such as the James Webb Space Telescope. The moderate eccentricity of planet b may be the result of Kozai-Lidov oscillations.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 3.0+2.6 −0.1[10] MJ |
4.607±0.039 | 9.72±0.03 | 0.239±0.001 | 78±40[10]° | — |
| c | 19.4+0.8 −0.5 MJ |
21.5+0.5 −0.4 |
97.1+3.4 −2.5 |
0.114+0.002 −0.003 |
40±2° | — |