HD 47366 b
Astrophysical Synthesis & Habitability Characterization
HD 47366 b is a confirmed gas giant exoplanet orbiting the star HD 47366, located approximately 275.1 light-years (84.36 parsecs) from the Solar System. First announced in 2016 by Okayama Astrophysical Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.4 Earth radii (1.2 Jupiter radii) and has a measured mass of 661.719 Earth masses (2.08 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.52 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.69 g⊕ (36.19 m/s²), and an escape velocity of 78.6 km/s.
In its orbital architecture around HD 47366, HD 47366 b completes one full revolution every 360.08 Earth days at a semi-major axis of 1.207 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 36.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.071 carries the world between 1.1213 AU at periapsis and 1.2927 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 577 K (+304°C / +579°F) and receiving 17.92 S⊕ (~24,383 W/m²), HD 47366 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 47366 is classified as an orange K-type star of spectral type K1 III with an effective photospheric temperature of 4,866 K, a radius of 7.3 R☉, a mass of 1.81 M☉, an estimated bolometric luminosity of 26.806 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.61 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, HD 47366 shines at apparent V-band magnitude 6.112 (visible to the unaided human eye under dark skies) in the Southern celestial hemisphere. The HD 47366 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 47366 b sharing its stellar neighborhood alongside HD 47366 c.
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: Okayama Astrophysical Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 47366 |
| Spectral Type | K1 III |
| Effective Temp (Teff) | 4,866 K |
| Stellar Radius | 7.3000 R☉ |
| Stellar Mass | 1.8100 M☉ |
| Bolometric Luminosity | 26.806 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 1.610 Gyr |
| Apparent Magnitude | V: 6.112 · G: 5.839 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.207000 AU |
| Orbital Period | 360.08 days |
| Mean Orbital Velocity | 36.5 km/s |
| Orbital Eccentricity (e) | 0.07100 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.52 g/cm³ (78.6 km/s vesc) |
| Insolation Flux | 17.9154 S⊕ (~24,383 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 275.100 LY (84.355 pc) |