GJ 3779 b
Astrophysical Synthesis & Habitability Characterization
GJ 3779 b is a confirmed sub-neptune exoplanet orbiting the star GJ 3779, located approximately 44.8 light-years (13.74 parsecs) from the Solar System. First announced in 2018 by Calar Alto Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.75 Earth radii and has a measured mass of 8 Earth masses. Combining its mass and radius yields a mean bulk density of 2.12 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 19.1 km/s.
In its orbital architecture around GJ 3779, GJ 3779 b completes one full revolution every 3.023 Earth days at a semi-major axis of 0.026 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 93.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.07 carries the world between 0.0242 AU at periapsis and 0.0278 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 527 K (+254°C / +489°F) and receiving 12.83 S⊕ (~17,455 W/m²), GJ 3779 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star GJ 3779 is classified as a low-mass red dwarf of spectral type M4.0 V with an effective photospheric temperature of 3,324 K, a radius of 0.281 R☉, a mass of 0.27 M☉, an estimated bolometric luminosity of 0.00865 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, GJ 3779 shines at apparent V-band magnitude 13.04 (faint and requiring research-grade or CCD telescopic photometry) 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: Calar Alto Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 3779 |
| Spectral Type | M4.0 V |
| Effective Temp (Teff) | 3,324 K |
| Stellar Radius | 0.2810 R☉ |
| Stellar Mass | 0.2700 M☉ |
| Bolometric Luminosity | 0.00865 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.040 · G: 11.627 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.026000 AU |
| Orbital Period | 3.023 days |
| Mean Orbital Velocity | 93.6 km/s |
| Orbital Eccentricity (e) | 0.07000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.12 g/cm³ (19.1 km/s vesc) |
| Insolation Flux | 12.8254 S⊕ (~17,455 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 44.800 LY (13.743 pc) |