GJ 2056 b
Astrophysical Synthesis & Habitability Characterization
GJ 2056 b is a confirmed sub-neptune exoplanet orbiting the star GJ 2056, located approximately 92.8 light-years (28.44 parsecs) from the Solar System. First announced in 2020 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 4.17 Earth radii (0.37 Jupiter radii) and has a measured mass of 16.2 Earth masses. Combining its mass and radius yields a mean bulk density of 1.23 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.93 g⊕ (9.12 m/s²), and an escape velocity of 22 km/s.
In its orbital architecture around GJ 2056, GJ 2056 b completes one full revolution every 69.971 Earth days at a semi-major axis of 0.283 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 44 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.72, swinging from 0.0792 AU at periapsis out to 0.4868 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 4.170 R⊕, GJ 2056 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 2056 is classified as a low-mass red dwarf of spectral type M0V: with an effective photospheric temperature of 4,070 K, a radius of 0.7095 R☉, a mass of 0.62 M☉, an estimated bolometric luminosity of 0.124 L☉. From Earth, GJ 2056 shines at apparent V-band magnitude 10.37 (faint and requiring research-grade or CCD telescopic photometry) 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 2056 |
| Spectral Type | M0V: |
| Effective Temp (Teff) | 4,070 K |
| Stellar Radius | 0.7095 R☉ |
| Stellar Mass | 0.6200 M☉ |
| Bolometric Luminosity | 0.124 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 10.370 · G: 9.723 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.283000 AU |
| Orbital Period | 69.971 days |
| Mean Orbital Velocity | 44 km/s |
| Orbital Eccentricity (e) | 0.72000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.23 g/cm³ (22 km/s vesc) |
| Insolation Flux | 1.5537 S⊕ (~2,115 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 92.800 LY (28.443 pc) |