HD 112640 b
Astrophysical Synthesis & Habitability Characterization
HD 112640 b is a confirmed gas giant exoplanet orbiting the star HD 112640, located approximately 1054.6 light-years (323.34 parsecs) from the Solar System. First announced in 2020 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 12.9 Earth radii (1.15 Jupiter radii) and has a measured mass of 1589.15 Earth masses (5 Jupiter masses). Combining its mass and radius yields a mean bulk density of 4.08 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 9.55 g⊕ (93.65 m/s²), and an escape velocity of 124.2 km/s.
In its orbital architecture around HD 112640, HD 112640 b completes one full revolution every 613.2 Earth days (1.68Julian years) at a semi-major axis of 1.7 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 30.2 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.24 carries the world between 1.292 AU at periapsis and 2.108 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 98.10 S⊕ (~133,510 W/m²), HD 112640 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 112640 is classified as an orange K-type star of spectral type K0 III with an effective photospheric temperature of 4,155 K, a radius of 39 R☉, a mass of 1.8 M☉, an estimated bolometric luminosity of 406.727 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.6 Gyr and a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, HD 112640 shines at apparent V-band magnitude 6.536 (accessible to binoculars and small amateur telescopes) 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 112640 |
| Spectral Type | K0 III |
| Effective Temp (Teff) | 4,155 K |
| Stellar Radius | 39.0000 R☉ |
| Stellar Mass | 1.8000 M☉ |
| Bolometric Luminosity | 406.727 L☉ |
| Metallicity [Fe/H] | -0.090 dex |
| Stellar Age | 1.600 Gyr |
| Apparent Magnitude | V: 6.536 · G: 6.077 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.700000 AU |
| Orbital Period | 613.2 days |
| Mean Orbital Velocity | 30.2 km/s |
| Orbital Eccentricity (e) | 0.24000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 4.08 g/cm³ (124.2 km/s vesc) |
| Insolation Flux | 98.0969 S⊕ (~133,510 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1054.600 LY (323.335 pc) |