| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Draco |
| Right ascension | 17h25m 24.055s[1] |
| Declination | 52° 47′ 26.47″[1] |
| Apparent magnitude (V) | 6.46[2] |
| Characteristics | |
| HD 158259 | |
| Evolutionary stage | Main sequence |
| Spectral type | G0[2] (G5VmF9[3]) |
| Astrometry | |
| Radial velocity (Rv) | 13.44±0.14[1] km/s |
| Proper motion (μ) | RA: −90.678[1] mas/yr Dec.: −49.702[1] mas/yr |
| Parallax (π) | 37.0177 ± 0.0199 mas[1] |
| Distance | 88.11 ± 0.05 ly (27.01 ± 0.01 pc) |
| Absolute magnitude (MV) | 4.27[4] |
| Details | |
| Mass | 0.985[1] M☉ |
| Radius | 1.3[1] R☉ |
| Luminosity | 1.6[1] L☉ |
| Surface gravity (log g) | 4.28[5] cgs |
| Temperature | 6,068[5] K |
| Metallicity [Fe/H] | −0.20[5] dex |
| Rotation | 18 days[2] |
| Rotational velocity (v sin i) | 3.0[6] km/s |
| Other designations | |
HIP 85268, 2MASS J17252406+5247263, TYC 3888-1886-1, TOI-1462, GSC 03888-01886[7] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 158259 is a main sequence star located 88 light-years (27parsecs) away in the constellation Draco. It hosts a system of at least five planets, discovered by the SOPHIE échelle spectrograph using the radial velocity method.[2]
HD 158259 is a G0 star with a rotation period of 18±5 days. More detailed analysis of the spectral assigns a class of G5V, but with the metal lines of an F9 star.[3]
Five planets have been confirmed orbiting HD 158259, along with one unconfirmed planet. These planets were discovered by N.C. Hara et.al. by the radial velocity method, published in Astronomy & Astrophysics in April 2020.[8] The innermost planet, HD 158259 b, was also observed to transit the star by TESS.[2] The planets orbit in a nearly 3:2 orbital resonance, with the period ratios 1.5758, 1.5146, 1.5296, 1.5130, and 1.4480, respectively, starting from the innermost pairing.[9] A dynamical analysis has shown that the system is stable.[2] One of the planets, HD 158259 b, is a super-Earth; the rest, including the unconfirmed HD 158259 g, are mini-Neptunes.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 2.2 M🜨 | 0.034 | 2.177±0.44 | <0.1 | — | ~1.2 R🜨 |
| c | 5.6 M🜨 | 0.046 | 3.432±0.00002 | <0.1 | — | — |
| d | 5.4 M🜨 | 0.060 | 5.198±0.008 | <0.1 | — | — |
| e | 6.1 M🜨 | 0.080 | 7.954±0.0016 | <0.1 | — | — |
| f | 6.1 M🜨 | 0.105 | 12.03±0.0028 | <0.1 | — | — |
| g (unconfirmed) | 6.9 M🜨 | 0.135 | 17.39±0.023 | <0.1 | — | — |
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