GJ 96 b
Astrophysical Synthesis & Habitability Characterization
GJ 96 b is a confirmed sub-neptune exoplanet orbiting the star GJ 96, located approximately 38.9 light-years (11.93 parsecs) from the Solar System. First announced in 2018 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 4.67 Earth radii (0.42 Jupiter radii) and has a measured mass of 19.66 Earth masses. Combining its mass and radius yields a mean bulk density of 1.06 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.9 g⊕ (8.83 m/s²), and an escape velocity of 23 km/s.
In its orbital architecture around GJ 96, GJ 96 b completes one full revolution every 73.94 Earth days at a semi-major axis of 0.291 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 42.8 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.44, swinging from 0.163 AU at periapsis out to 0.419 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 4.670 R⊕, GJ 96 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 96 is classified as a low-mass red dwarf of spectral type M2 with an effective photospheric temperature of 3,785 K, a radius of 0.5806 R☉, a mass of 0.6 M☉, an estimated bolometric luminosity of 0.062 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.14 dex (metal-rich relative to the Sun). From Earth, GJ 96 shines at apparent V-band magnitude 9.4 (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 | GJ 96 |
| Spectral Type | M2 |
| Effective Temp (Teff) | 3,785 K |
| Stellar Radius | 0.5806 R☉ |
| Stellar Mass | 0.6000 M☉ |
| Bolometric Luminosity | 0.062 L☉ |
| Metallicity [Fe/H] | 0.140 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 9.400 · G: 8.632 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.291000 AU |
| Orbital Period | 73.94 days |
| Mean Orbital Velocity | 42.8 km/s |
| Orbital Eccentricity (e) | 0.44000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.06 g/cm³ (23 km/s vesc) |
| Insolation Flux | 1.0486 S⊕ (~1,427 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 38.900 LY (11.932 pc) |