GJ 414 A b
Astrophysical Synthesis & Habitability Characterization
GJ 414 A b is a confirmed sub-neptune exoplanet orbiting the star GJ 414 A, located approximately 38.8 light-years (11.89 parsecs) from the Solar System. First announced in 2021 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 2.63 Earth radii and has a measured mass of 7.6 Earth masses. Combining its mass and radius yields a mean bulk density of 2.3 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.1 g⊕ (10.79 m/s²), and an escape velocity of 19 km/s.
In its orbital architecture around GJ 414 A, GJ 414 A b completes one full revolution every 50.8 Earth days at a semi-major axis of 0.2324 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 49.8 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.45, swinging from 0.1278 AU at periapsis out to 0.337 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 2.630 R⊕, GJ 414 A b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star GJ 414 A is classified as an orange K-type star of spectral type K7 V with an effective photospheric temperature of 4,120 K, a radius of 0.68 R☉, a mass of 0.65 M☉, an estimated bolometric luminosity of 0.12 L☉. Stellar evolution modeling indicates an estimated stellar age of 12.4 Gyr and a metallicity of [Fe/H] = 0.24 dex (metal-rich relative to the Sun). From Earth, GJ 414 A shines at apparent V-band magnitude 8.31 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The GJ 414 A system is a multi-planet architecture hosting 2 confirmed worlds, with GJ 414 A b sharing its stellar neighborhood alongside GJ 414 A 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 414 A |
| Spectral Type | K7 V |
| Effective Temp (Teff) | 4,120 K |
| Stellar Radius | 0.6800 R☉ |
| Stellar Mass | 0.6500 M☉ |
| Bolometric Luminosity | 0.12 L☉ |
| Metallicity [Fe/H] | 0.240 dex |
| Stellar Age | 12.400 Gyr |
| Apparent Magnitude | V: 8.310 · G: 7.728 |
| System Architecture | 2 Stars, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.232400 AU |
| Orbital Period | 50.8 days |
| Mean Orbital Velocity | 49.8 km/s |
| Orbital Eccentricity (e) | 0.45000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.3 g/cm³ (19 km/s vesc) |
| Insolation Flux | 2.2033 S⊕ (~2,999 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 38.800 LY (11.889 pc) |