HD 224693 b
Astrophysical Synthesis & Habitability Characterization
HD 224693 b is a confirmed gas giant exoplanet orbiting the star HD 224693, located approximately 305 light-years (93.5 parsecs) from the Solar System. First announced in 2006 by W. M. Keck Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 14 Earth radii (1.25 Jupiter radii) and has a measured mass of 222.481 Earth masses (0.7 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.45 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.14 g⊕ (11.18 m/s²), and an escape velocity of 44.6 km/s.
In its orbital architecture around HD 224693, HD 224693 b completes one full revolution every 26.69 Earth days at a semi-major axis of 0.191 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 77.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.104 carries the world between 0.1711 AU at periapsis and 0.2109 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 903 K (+630°C / +1166°F) and receiving 111.67 S⊕ (~151,982 W/m²), HD 224693 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 224693 is classified as a solar-type yellow star of spectral type G2 V with an effective photospheric temperature of 5,894 K, a radius of 1.93 R☉, a mass of 1.31 M☉, an estimated bolometric luminosity of 4.033 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.12 Gyr and a metallicity of [Fe/H] = 0.27 dex (metal-rich relative to the Sun). From Earth, HD 224693 shines at apparent V-band magnitude 8.23 (accessible to binoculars and small amateur telescopes) 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 224693 |
| Spectral Type | G2 V |
| Effective Temp (Teff) | 5,894 K |
| Stellar Radius | 1.9300 R☉ |
| Stellar Mass | 1.3100 M☉ |
| Bolometric Luminosity | 4.033 L☉ |
| Metallicity [Fe/H] | 0.270 dex |
| Stellar Age | 4.120 Gyr |
| Apparent Magnitude | V: 8.230 · G: 8.085 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.191000 AU |
| Orbital Period | 26.69 days |
| Mean Orbital Velocity | 77.9 km/s |
| Orbital Eccentricity (e) | 0.10400 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.45 g/cm³ (44.6 km/s vesc) |
| Insolation Flux | 111.6692 S⊕ (~151,982 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 305.000 LY (93.502 pc) |