HD 158259 b
Astrophysical Synthesis & Habitability Characterization
HD 158259 b is a confirmed super-earth exoplanet orbiting the star HD 158259, located approximately 88.2 light-years (27.05 parsecs) from the Solar System. First announced in 2020 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 1.282 Earth radii and has a measured mass of 2.22 Earth masses. Combining its mass and radius yields a mean bulk density of 5.81 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.35 g⊕ (13.24 m/s²), and an escape velocity of 14.7 km/s.
In its orbital architecture around HD 158259, HD 158259 b completes one full revolution every 2.178 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1462 K (+1189°C / +2172°F) and receiving 759.18 S⊕ (~1,033,248 W/m²), HD 158259 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 158259 is classified as a solar-type yellow star of spectral type G0 with an effective photospheric temperature of 5,802 K, a radius of 1.21 R☉, a mass of 1.08 M☉, an estimated bolometric luminosity of 1.489 L☉. From Earth, HD 158259 shines at apparent V-band magnitude 6.479 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 158259 system is a multi-planet architecture hosting 5 confirmed worlds, with HD 158259 b sharing its stellar neighborhood alongside HD 158259 c, HD 158259 d, HD 158259 e, HD 158259 f.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: Haute-Provence Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 158259 |
| Spectral Type | G0 |
| Effective Temp (Teff) | 5,802 K |
| Stellar Radius | 1.2100 R☉ |
| Stellar Mass | 1.0800 M☉ |
| Bolometric Luminosity | 1.489 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 6.479 · G: 6.307 |
| System Architecture | 1 Star, 5 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 2.178 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.81 g/cm³ (14.7 km/s vesc) |
| Insolation Flux | 759.1830 S⊕ (~1,033,248 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 88.200 LY (27.050 pc) |