GJ 3293 c
Astrophysical Synthesis & Habitability Characterization
GJ 3293 c is a confirmed sub-neptune exoplanet orbiting the star GJ 3293, located approximately 65.9 light-years (20.19 parsecs) from the Solar System. First announced in 2015 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 4.87 Earth radii (0.43 Jupiter radii) and has a measured mass of 21.09 Earth masses. Combining its mass and radius yields a mean bulk density of 1.01 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.89 g⊕ (8.73 m/s²), and an escape velocity of 23.3 km/s.
In its orbital architecture around GJ 3293, GJ 3293 c completes one full revolution every 122.62 Earth days at a semi-major axis of 0.36175 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 32.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.11 carries the world between 0.322 AU at periapsis and 0.4015 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 177 K (-96°C / -141°F) and an incident flux of 0.17 S⊕ (~231 W/m²), surface water and volatile species on GJ 3293 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star GJ 3293 is classified as a low-mass red dwarf of spectral type M2.5 with an effective photospheric temperature of 3,466 K, a radius of 0.404 R☉, a mass of 0.42 M☉, an estimated bolometric luminosity of 0.021 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.02 dex (near-solar heavy-element abundance). From Earth, GJ 3293 shines at apparent V-band magnitude 11.945 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The GJ 3293 system is a multi-planet architecture hosting 4 confirmed worlds, with GJ 3293 c sharing its stellar neighborhood alongside GJ 3293 e, GJ 3293 b, GJ 3293 d.
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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 3293 |
| Spectral Type | M2.5 |
| Effective Temp (Teff) | 3,466 K |
| Stellar Radius | 0.4040 R☉ |
| Stellar Mass | 0.4200 M☉ |
| Bolometric Luminosity | 0.021 L☉ |
| Metallicity [Fe/H] | 0.020 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 11.945 · G: 10.979 |
| System Architecture | 1 Star, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.361750 AU |
| Orbital Period | 122.62 days |
| Mean Orbital Velocity | 32.1 km/s |
| Orbital Eccentricity (e) | 0.11000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.01 g/cm³ (23.3 km/s vesc) |
| Insolation Flux | 0.1700 S⊕ (~231 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 65.900 LY (20.190 pc) |