GJ 433 c
Astrophysical Synthesis & Habitability Characterization
GJ 433 c is a confirmed gas giant exoplanet orbiting the star GJ 433, located approximately 29.6 light-years (9.07 parsecs) from the Solar System. First announced in 2014 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 6.27 Earth radii (0.56 Jupiter radii) and has a measured mass of 32.422 Earth masses (0.1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.73 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.82 g⊕ (8.04 m/s²), and an escape velocity of 25.4 km/s.
In its orbital architecture around GJ 433, GJ 433 c completes one full revolution every 5094.105 Earth days (13.95Julian years) at a semi-major axis of 4.819 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 10.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.12 carries the world between 4.2407 AU at periapsis and 5.3973 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 54 K (-219°C / -362°F) and an incident flux of 0.00 S⊕ (~1 W/m²), surface water and volatile species on GJ 433 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star GJ 433 is classified as a low-mass red dwarf of spectral type M2V with an effective photospheric temperature of 3,461 K, a radius of 0.5 R☉, a mass of 0.48 M☉, an estimated bolometric luminosity of 0.032 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, GJ 433 shines at apparent V-band magnitude 9.81 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The GJ 433 system is a multi-planet architecture hosting 3 confirmed worlds, with GJ 433 c sharing its stellar neighborhood alongside GJ 433 b, GJ 433 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 433 |
| Spectral Type | M2V |
| Effective Temp (Teff) | 3,461 K |
| Stellar Radius | 0.5000 R☉ |
| Stellar Mass | 0.4800 M☉ |
| Bolometric Luminosity | 0.032 L☉ |
| Metallicity [Fe/H] | -0.170 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 9.810 · G: 8.891 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 4.819000 AU |
| Orbital Period | 5094.105 days |
| Mean Orbital Velocity | 10.3 km/s |
| Orbital Eccentricity (e) | 0.12000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.73 g/cm³ (25.4 km/s vesc) |
| Insolation Flux | 0.0009 S⊕ (~1 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 29.600 LY (9.065 pc) |