HD 113996 b
Astrophysical Synthesis & Habitability Characterization
HD 113996 b is a confirmed gas giant exoplanet orbiting the star HD 113996, located approximately 379.4 light-years (116.33 parsecs) from the Solar System. First announced in 2017 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 12.7 Earth radii (1.13 Jupiter radii) and has a measured mass of 2002.329 Earth masses (6.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 5.39 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 12.41 g⊕ (121.7 m/s²), and an escape velocity of 140.5 km/s.
In its orbital architecture around HD 113996, HD 113996 b completes one full revolution every 610.2 Earth days (1.67Julian years) at a semi-major axis of 1.6 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 28.5 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.28, swinging from 1.152 AU at periapsis out to 2.048 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 799 K (+526°C / +979°F) and receiving 113.67 S⊕ (~154,707 W/m²), HD 113996 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 113996 is classified as an orange K-type star of spectral type K5 III with an effective photospheric temperature of 4,181 K, a radius of 25.11 R☉, a mass of 1.49 M☉, an estimated bolometric luminosity of 172.864 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.24 Gyr and a metallicity of [Fe/H] = 0.13 dex (metal-rich relative to the Sun). From Earth, HD 113996 shines at apparent V-band magnitude 4.77 (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 113996 |
| Spectral Type | K5 III |
| Effective Temp (Teff) | 4,181 K |
| Stellar Radius | 25.1100 R☉ |
| Stellar Mass | 1.4900 M☉ |
| Bolometric Luminosity | 172.864 L☉ |
| Metallicity [Fe/H] | 0.130 dex |
| Stellar Age | 3.240 Gyr |
| Apparent Magnitude | V: 4.770 · G: 4.223 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.600000 AU |
| Orbital Period | 610.2 days |
| Mean Orbital Velocity | 28.5 km/s |
| Orbital Eccentricity (e) | 0.28000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.39 g/cm³ (140.5 km/s vesc) |
| Insolation Flux | 113.6719 S⊕ (~154,707 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 379.400 LY (116.334 pc) |