HD 47536 b
Astrophysical Synthesis & Habitability Characterization
HD 47536 b is a confirmed gas giant exoplanet orbiting the star HD 47536, located approximately 399.7 light-years (122.54 parsecs) from the Solar System. First announced in 2002 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.6 Earth radii (1.12 Jupiter radii) and has a measured mass of 2330 Earth masses (7.33 Jupiter masses). Combining its mass and radius yields a mean bulk density of 6.42 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 14.68 g⊕ (143.96 m/s²), and an escape velocity of 152.1 km/s.
In its orbital architecture around HD 47536, HD 47536 b completes one full revolution every 712.13 Earth days (1.95Julian years) at a semi-major axis of 1.93 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 29.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.2 carries the world between 1.544 AU at periapsis and 2.316 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 737 K (+464°C / +867°F) and receiving 47.57 S⊕ (~64,743 W/m²), HD 47536 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 47536 is classified as an orange K-type star of spectral type K1 III with an effective photospheric temperature of 4,380 K, a radius of 23.47 R☉, a mass of 2.1 M☉, an estimated bolometric luminosity of 181.892 L☉. Stellar evolution modeling indicates an estimated stellar age of 10.15 Gyr and a metallicity of [Fe/H] = -0.65 dex (metal-poor relative to the Sun). From Earth, HD 47536 shines at apparent V-band magnitude 5.25 (visible to the unaided human eye under dark skies) in the Southern 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 47536 |
| Spectral Type | K1 III |
| Effective Temp (Teff) | 4,380 K |
| Stellar Radius | 23.4700 R☉ |
| Stellar Mass | 2.1000 M☉ |
| Bolometric Luminosity | 181.892 L☉ |
| Metallicity [Fe/H] | -0.650 dex |
| Stellar Age | 10.150 Gyr |
| Apparent Magnitude | V: 5.250 · G: 4.880 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.930000 AU |
| Orbital Period | 712.13 days |
| Mean Orbital Velocity | 29.5 km/s |
| Orbital Eccentricity (e) | 0.20000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 6.42 g/cm³ (152.1 km/s vesc) |
| Insolation Flux | 47.5699 S⊕ (~64,743 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 399.700 LY (122.536 pc) |