HD 211403 b
Astrophysical Synthesis & Habitability Characterization
HD 211403 b is a confirmed gas giant exoplanet orbiting the star HD 211403, located approximately 271 light-years (83.09 parsecs) from the Solar System. First announced in 2021 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.8 Earth radii (1.14 Jupiter radii) and has a measured mass of 1760.769 Earth masses (5.54 Jupiter masses). Combining its mass and radius yields a mean bulk density of 4.63 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 10.75 g⊕ (105.42 m/s²), and an escape velocity of 131.2 km/s.
In its orbital architecture around HD 211403, HD 211403 b completes one full revolution every 223.8 Earth days at a semi-major axis of 0.768 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 37.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.084 carries the world between 0.7035 AU at periapsis and 0.8325 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 380 K (+107°C / +225°F) and receiving 3.44 S⊕ (~4,682 W/m²), HD 211403 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 211403 is classified as a warm F-type star of spectral type F7 V with an effective photospheric temperature of 6,273 K, a radius of 1.206 R☉, a mass of 1.2 M☉, an estimated bolometric luminosity of 2.021 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.18 dex (metal-rich relative to the Sun). From Earth, HD 211403 shines at apparent V-band magnitude 8.48 (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: Haute-Provence Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 211403 |
| Spectral Type | F7 V |
| Effective Temp (Teff) | 6,273 K |
| Stellar Radius | 1.2060 R☉ |
| Stellar Mass | 1.2000 M☉ |
| Bolometric Luminosity | 2.021 L☉ |
| Metallicity [Fe/H] | 0.180 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.480 · G: 8.349 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.768000 AU |
| Orbital Period | 223.8 days |
| Mean Orbital Velocity | 37.3 km/s |
| Orbital Eccentricity (e) | 0.08400 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 4.63 g/cm³ (131.2 km/s vesc) |
| Insolation Flux | 3.4400 S⊕ (~4,682 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 271.000 LY (83.092 pc) |