HD 158996 b
Astrophysical Synthesis & Habitability Characterization
HD 158996 b is a confirmed gas giant exoplanet orbiting the star HD 158996, located approximately 925.2 light-years (283.66 parsecs) from the Solar System. First announced in 2018 by Bohyunsan Optical Astronomical Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.3 Earth radii (1.1 Jupiter radii) and has a measured mass of 4449.62 Earth masses (14 Jupiter masses). Combining its mass and radius yields a mean bulk density of 13.18 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 29.41 g⊕ (288.41 m/s²), and an escape velocity of 212.8 km/s.
In its orbital architecture around HD 158996, HD 158996 b completes one full revolution every 820.2 Earth days (2.25Julian years) at a semi-major axis of 2.1 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 27.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.13 carries the world between 1.827 AU at periapsis and 2.373 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 960 K (+687°C / +1269°F) and receiving 234.63 S⊕ (~319,326 W/m²), HD 158996 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 158996 is classified as an orange K-type star of spectral type K5 III with an effective photospheric temperature of 4,069 K, a radius of 50.3 R☉, a mass of 1.8 M☉, an estimated bolometric luminosity of 622.267 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.6 Gyr and a metallicity of [Fe/H] = -0.2 dex (metal-poor relative to the Sun). From Earth, HD 158996 shines at apparent V-band magnitude 5.723 (visible to the unaided human eye under dark skies) in the Northern celestial hemisphere.
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: Bohyunsan Optical Astronomical Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 158996 |
| Spectral Type | K5 III |
| Effective Temp (Teff) | 4,069 K |
| Stellar Radius | 50.3000 R☉ |
| Stellar Mass | 1.8000 M☉ |
| Bolometric Luminosity | 622.267 L☉ |
| Metallicity [Fe/H] | -0.200 dex |
| Stellar Age | 1.600 Gyr |
| Apparent Magnitude | V: 5.723 · G: 5.186 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.100000 AU |
| Orbital Period | 820.2 days |
| Mean Orbital Velocity | 27.9 km/s |
| Orbital Eccentricity (e) | 0.13000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 13.18 g/cm³ (212.8 km/s vesc) |
| Insolation Flux | 234.6259 S⊕ (~319,326 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 925.200 LY (283.659 pc) |